Systematic Review and Meta-Analysis of Urban Air Quality in the Arabian Peninsula

Abstract

Air pollution is causing a global health, climate, and environmental crisis. Air quality (AQ) in hyper-arid regions, such as the Arabian Peninsula, remains under-explored, posing significant concerns for public health and the scientific community. Both long-term and short-term exposure to high pollutant levels, whether from anthropogenic or natural sources, can pose serious health risks. This paper offers a comprehensive review and meta-analysis of urban AQ literature published in the region over the past decade (2013–June 2025). We aim to provide guidance and highlight key directions for future research in the field. This paper examines key pollutants, emission sources, implications of urban sources, and the most studied countries, methodologies, limitations, and recommendations from different case studies. Our analysis reveals a significant research gap highlighting insufficient recent literature. Saudi Arabia was the most studied country with 20 papers, followed by the broader Arabian Peninsula (sixteen), Qatar (twelve), the United Arab Emirates and Iraq (seven each), Kuwait (four), Oman (three), Jordan, and Bahrain (one each). The primary methods employed included measurements and sampling (28%) and remote sensing (24%), with a focus on pollutants such as dust (23.1%), NO_x/NO₂/NO (17.2%), PM_2.5 (17.6%), and PM₁₀ (12%). Industrial emissions (27%) and natural dust (24%) were identified as significant emission sources. Monitoring methods included grab sampling (19%), integrated sampling (34%), and continuous monitoring (47%). Notably, 13.3% of AQ sensors were linked to a station, 27.6% were self-referenced, and 59.1% did not specify calibration methods. The findings highlight the need for further research, regular calibration of air quality monitors, and the integration of advanced modeling approaches. Moreover, we recommend exploring the links between air pollution and urban development to ensure cleaner air and contribute to the global dialogue on sustainable and cross-border AQ solutions.

1. Introduction

Long-term personal exposure to air pollution and short-term exposure to high concentrations of air pollutants are pressing concerns in scientific research and public health discourse [1,2]. According to the World Health Organization (WHO), around 99% of the world’s population breathes air containing pollutant concentrations that exceed the WHO’s global guideline limits [3]. Globally, air pollution is responsible for more than 6.7 million premature deaths annually, with vulnerable groups such as children, pregnant women, older adults, and individuals with pre-existing respiratory conditions being at greater risk [1,4]. The health impacts of air pollution include but are not limited to lung cancer [5,6], respiratory diseases, heart infections [7,8], heart attacks, strokes, and asthma [9,10]. Beyond health impacts, air pollution also harms the environment through global warming [11], the formation of acid rain [12], ozone depletion [13], and weather variability [14]. However, not all pollutants have the same impact. In fact, the recent updates to air quality (AQ) guidelines published by the WHO in September 2021 are significantly stricter for specific critical air pollutants. For instance, for particulate matter with an aerodynamic diameter of 2.5 μm (PM_2.5) or less, the annual average limit is now 5 µg/m³; for particulate matter up to 10 μm (PM₁₀), the limit is 15 µg/m³; and for nitrogen dioxide (NO₂), the limit is 10 µg/m³ [3]. These limits and other information for different pollutants are detailed in the WHO’s 2021 report [3].

In urban areas, adhering to these guidelines often presents substantial challenges [15,16]. The high population density in urban areas is closely linked to elevated emissions from various sources, including natural gas and fuel oil used for home heating [17,18], extensive vehicle traffic [19,20,21], and intense levels of product manufacturing and industrial activities [22,23,24]. These factors contribute to the complexity of reducing pollutant levels by targeting and meeting the recommended guidelines. In addition, countries in the Arabian Peninsula (i.e., Bahrain, Kuwait, Iraq, Oman, Qatar, Saudi Arabia, the United Arab Emirates, Yemen, and Jordan) must deal with natural sources. The region’s unique desert environment introduces additional complexities to AQ management [25]. This region is characterized by high temperatures and varying humidity levels, with low humidity in deserts and high humidity in coastal areas [26], as well as frequent dust storms [27], rapid urbanization [28], economic growth [29], increased energy consumption [30], and industrialization. These factors collectively have a significant impact on AQ [31].

Over the past 10 years, significant attention has been given to urban AQ in the Arabian Peninsula. The existing studies provide a comprehensive overview of urban-focused AQ research, demonstrating that while substantial progress has been made, further studies are still needed to fully understand and address the region’s unique challenges. Rapid urbanization and population growth in the Arabian Peninsula have led to increased vehicular traffic, making transportation a major source of air pollution. Studies have consistently linked urban pollution to vehicle emissions, as seen in Saudi Arabia [1,32], Qatar [25,29,31], and Kuwait [33], highlighting the need for effective traffic management to mitigate air pollutants. The region’s reliance on oil production, refining, and manufacturing has led to significant industrial emissions. For instance, the industrial zones in Kuwait release significant SO₂ and NO₂ emissions, necessitating real-time monitoring and stricter regulations on cement, metal, and stone-cutting industries [34,35]. Additionally, the frequent sand and dust storms, driven by arid desert conditions, exacerbate air pollution by increasing PM pollution across the region [29], with high aerosol optical depth (AOD) [36].

In this study, we aim to provide a comprehensive review and meta-analysis of published papers on urban AQ in the Arabian Peninsula from 2013 to June 2025. Given the growing significance of the issue, as highlighted in the background literature, we also seek to offer insights and directions for future research in the region. To achieve this aim, we addressed the most studied air pollutants, potential emission sources, most understudied areas, and the types of AQ monitoring devices and models most frequently used. Additionally, we examined data collection methods, spatial and temporal coverage, the calibration and accuracy of monitoring devices, the implications of urban sources on AQ, and key limitations and recommendations provided in the reviewed literature. This study contributes to advancing the current understanding of urban AQ and guiding future research and policy development to improve AQ management practices worldwide but with a focus on the Arabian Peninsula. We developed and applied a thematic methodology to extract consistent information from each reviewed study. This includes (1) assessing the current state and identifying significant research gaps, (2) evaluating essential tools and elements in material and experimental design, and (3) analyzing case studies and their resulting outcomes. Our study is the first to systematically review the rapidly expanding field of urban AQ in the Arabian Peninsula over the past decade. The developed methodology is highly transferable to other systematic reviews, minimizing author biases and focusing on knowledge extracted from the literature. This methodology provides quantitative and qualitative references for future applications to improve urban AQ globally. It is relevant to AQ researchers, scholars, and experts at all levels working to improve public health and protect the environment by addressing urban air pollution.

2. Methodology

2.1. Study Area

The Arabian Peninsula (Figure 1), located in the southwestern part of Asia in the subtropical belt between 12° and 35° N latitude and 30° and 60° W longitude, is the largest peninsula in the world, covering approximately 3.2 million Km² [26]. The Red Sea borders it to the west, the Arabian Sea to the south, the Gulf of Oman to the southeast, and the Persian Gulf to the northeast, with the Syrian Desert and Mesopotamian Plain to the north (Figure 1) [26,29]. The region has diverse geographical features, including vast deserts such as the Rub’ al Khali, the largest continuous sand desert globally [29]. The climate of the Arabian Peninsula is predominantly arid [37], with extreme heat during summer and minimal rainfall [38]; coastal areas experience milder temperatures and higher humidity compared to the interior, where harsh desert conditions prevail [26,29]. The southwestern highlands receive more rainfall due to their elevation [26,39].

The Arabian Peninsula consists of six countries, with parts of three additional countries extending onto it. The nations on the peninsula include Saudi Arabia, Oman, Kuwait, Qatar, Yemen, and the UAE. The southern areas of Jordan, Iraq, and Bahrain are also geopolitically associated with the peninsula [26,40]. The area encounters significant environmental challenges such as desertification, climate change, and declining AQ [26,29,40]. The region’s AQ is affected by natural factors (i.e., desert dust) and human activities (i.e., emissions from vehicles and industries). These activities encompass the rapidly expanding urban population, which leads to higher vehicle usage and emissions, industrialization, construction, emissions from ships in the Arabian Gulf, and the exploitation of natural resources [26,29,40]. These combined factors negatively affect AQ in the region, posing long-term public health and environmental sustainability concerns.

This study area was chosen due to a combination of several critical factors that uniquely impact urban AQ in the Arabian Peninsula. The region experiences intense anthropogenic pressure from rapid urban development (e.g., Riyadh, Dubai, and Doha), major infrastructure projects, and high vehicular density, contributing to increased NO₂, PM_2.5, and other pollutants. Additionally, natural phenomena such as frequent dust storms (e.g., the seasonal Shamal winds in Kuwait and eastern Saudi Arabia) significantly elevate particulate matter concentrations. The region’s reliance on desalination plants, oil refineries, and energy-intensive cooling systems further compounds pollution. These complex and region-specific drivers make the Arabian Peninsula an essential and scientifically valuable setting for targeted AQ assessment and synthesis.

2.2. Thematic Analysis Method

The thematic analysis research methodology identifies, analyzes, and provides consistent knowledge within various data sources, including interviews, transcripts, questionnaires, scientific publications, and news articles [41]. Braun and Clarke [41] described a thematic analysis framework in psychological studies, consisting of six steps, which served as the guiding structure for our method. Wang et al. [42] also employed this thematic analysis approach in the review of studies utilizing low-cost sensors for AQ monitoring on a global scale. Drawing from the foundational frameworks of Wang et al. [42] and Braun and Clarke [41], we developed a novel thematic methodology (Figure 2) to address (1) the current state of urban AQ and identify significant research gaps, (2) the essential tools and components involved in urban AQ studies’ material and experimental design, and (3) the analysis of urban AQ through case studies and the resulting outcomes. To ensure that the comprehensive review aligned with our objectives (outlined in the introduction), self-contained questions were developed for each stage. They were then answered through a meta-analysis. By addressing these questions, we provided critical insights into urban AQ in the Arabian Peninsula, offering valuable guidance for enhancing public health and environmental protection through the mitigation of urban air pollution.

2.3. Data Search, Extraction, and Screening Criteria

To gather the datasets for this study, we primarily utilized the Web of Science (WoS) and searched for peer-reviewed articles containing specific keyword terms, including “urban air quality”, “urban air pollution”, “Arabian Peninsula”, “Gulf countries”, “Bahrain”, “Kuwait”, “Iraq”, “Oman”, “Qatar”, “Saudi Arabia”, “United Arab Emirates”, “Yemen”, and “Jordan”. The representative connection network based on all keywords from the consulted review papers is presented in Figure 3. It is crucial to highlight the following: (1) This systematic review specifically targets research on urban AQ within the Arabian Peninsula, encompassing both qualitative and quantitative full-length original research articles, as well as academic reviews, theoretical discussions, and case studies indexed in the WoS. (2) We excluded non-peer-reviewed materials such as reports from government bodies, organizations, newspapers, media outlets, and other online sources. The database of papers was reviewed multiple times to avoid repetitions or duplicates. The following inclusion criteria were adopted for selecting the papers:

(1)

Full-length original research articles: We prioritized comprehensive, original research articles, which provide in-depth analysis and contribute new findings to the field. This criterion excludes brief reports, opinion pieces, editorials, and reviews, as our focus was on obtaining robust, data-driven studies that offer substantial evidence and insights into urban AQ.

(2)

English language: English was chosen as the required language for the selected studies to ensure consistency in terminology, facilitate peer review, and enable the wider dissemination of findings. This also allows for easier cross-referencing with other studies in the field, as English is the predominant language in international scientific publications.

(3)

Publication date between 2013 and June 2025: We focused on papers published within the last decade to capture the most current research, trends, and advancements in urban AQ. This period was selected to ensure that the review reflects recent developments in methodologies, technologies, and regulatory frameworks that have shaped the field.

(4)

Transparent methodology: The inclusion of studies with well-defined and transparent methodologies was crucial to ensure the validity and reliability of our results. This criterion encompassed a variety of methodological approaches such as sample collection, environmental monitoring, dispersion modeling, satellite data analysis, and systematic reviews. By including diverse methodologies, the review aims to provide a comprehensive understanding of the different techniques used to study urban AQ and their respective outcomes.

(5)

Urban AQ focus: The focus on urban AQ was chosen to address the specific environmental challenges faced by cities, particularly in densely populated and industrialized regions. These studies are essential for understanding the impact of urbanization on AQ, identifying key pollutants, and evaluating the effectiveness of air pollution measures in urban settings.

(6)

Studies in the Arabian Peninsula region (i.e., Bahrain, Kuwait, Iraq, Oman, Qatar, Saudi Arabia, the United Arab Emirates, Yemen, and Jordan): The geographical focus on the Arabian Peninsula was chosen due to the unique environmental, climatic, and socioeconomic factors that influence AQ in this region. These factors include high temperatures, frequent dust storms, rapid urbanization, and reliance on fossil fuels. The review aims to address region-specific urban AQ issues and provide insights directly applicable to these countries by concentrating on this region.

(7)

Overall screening based on title, abstract, and conclusion: This step was designed to efficiently filter out irrelevant or low-quality studies and ensure that only those with a clear focus on urban AQ and a strong research basis were selected for further review. By concentrating carefully on the evaluation of the title, abstract, and conclusion, we ensured that the chosen studies were directly relevant to the research objectives and provided valuable contributions to the systematic review.

In our preliminary search, the database platforms yielded 149,493 original studies. We utilized additional resources such as Scopus and PubMed to ensure the inclusion of all relevant studies. Based on selection criteria 1 to 3, we narrowed this down to 192 papers. Following criteria 4 to 6, 95 papers advanced to the following stage. Finally, based on criteria 7, only 71 papers progressed to the last review stage for meta-analysis (Figure 2). Ultimately, all 71 studies were confirmed to be indexed. All 71 scientific articles are thoroughly discussed and cited in this systematic review paper [2,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116].

2.4. Meta-Analysis and Data Categorization

After selecting 71 scientific articles for review, we conducted multiple evaluation rounds to ensure consistency and precision in our analysis. The meta-analysis systematically synthesized findings from diverse urban AQ studies, emphasizing the extraction of insights regarding AQ challenges in hyper-arid regions, i.e., the Arabian Peninsula. Each question was addressed during the meta-analysis using a thematic framework (Figure 2), which organized the findings into key categories. These categories included identifying the most studied air pollutants and areas, potential emission sources, monitoring devices, AQ models, data collection methods, spatial and temporal coverage, calibration, regional number of publications per year, and frequency of regional repetitive methodologies.

For each category,

Table 1. Normalized responses and definitions for thematic and meta-analysis methods in urban AQ studies.

Thematic Stages	Initial Theme	Normalized Response	Conceptual Description and Definition
Stage 1: Current state of the art and significant research gaps in urban AQ studies	Most studied air pollutants	Specific pollutant names	This initial theme identifies the names of air pollutants investigated in each paper. They might include dust, particulate matter (PM2.5, PM10), nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), and carbon monoxide (CO). Then, the study describes the air pollutants most frequently studied within the Arabian Peninsula from the sample of all examined pollutants.
	Potential emission sources of air pollutants	Specific names of urban air pollutant sources	Potential emission sources of air pollutants include all major contributors within the study areas (urban) that emit pollutants. These sources can be classified based on spatial characteristics and mobility: line sources (e.g., road traffic), point sources (e.g., industrial stacks), area sources (e.g., residential heating), volume sources (e.g., industrial facilities), stationary sources (fixed locations), and mobile sources (e.g., vehicles), among others.
	Most studied area	Specific name of country/region/city names	This initial theme identifies the locations within the Arabian Peninsula where the study was conducted, including countries, sub-regions, or cities. Then, the study describes the most studied areas within the Arabian Peninsula.
	Types and most used AQ monitoring devices	Specific device names/mobile and fixed monitors or Combined (semi-mobile) monitors	This initial theme identifies the AQ monitoring devices used in the study, focusing on classifications such as mobile monitors (portable and deployable) and fixed monitors (stationary and permanent). Then, the study describes the most frequently used AQ monitors within the Arabian Peninsula from the sample of all examined devices.
	Types and most used AQ models	Specific model names	Several types of AQ models are currently being used. This theme identifies the AQ models utilized in the studies and then describes the most frequently used model within the Arabian Peninsula from the sample of all examined models.
Stage 2: Essential tools and elements in material and experimental design	Data collection methods	Specific name	This theme provides a description of one or more AQ monitoring methods. These may include grab sampling (short-duration), integrated sampling (long-duration with filters or absorbents), automatic or continuous sampling using automated instruments, satellite data analysis, and other techniques.
	Spatial coverage	Specific name of country/region/city	This provides an overview of the spatial scope of monitoring devices, from small local urban areas with point-fixed monitors to larger regional areas. The monitors might have been operated at various points within the study area.
	Resolution of the modeling domain	Specific resolution scales	This provides an overview of the modeling and satellite AQ studies that provided resolution scales for the domain.
	Calibration of monitoring devices	Specific calibration technique	This theme provides an overview of the calibration of AQ monitors. Calibration establishes the reference (station data) to calibrate raw AQ data. Based on this definition, complementary raw datasets from the same source and instruments can be calibrated by self-reference. Calibration ensures the accuracy and reliability of AQ data.
	Accuracy of AQ models	Accuracy tests	Testing the accuracy of AQ models determines the applicability and reliability of the model output. This can be performed through cross-model validation (comparing model outputs for similar input data) and statistical comparison between modeling and measurements.
	Temporal coverage of AQ monitors and models	Specific temporal coverage	This theme provides an overview of the temporal scope of monitoring devices or models based on the results, which can be expressed using various temporal parameters, including hourly, daily (24 h), weekly, monthly, seasonally, and annually, among others.
	Analysis method or modeling techniques	Specific technique	This theme provides a description of the data analysis or modeling techniques used to obtain results. These techniques may include measurements, statistical models, satellite data, surveys, questionnaires, critical reviews, and trajectory models.
Stage 3: Analysis of case studies and their resulting outcomes	Implications of potential urban sources on the results	Explanations or specification	This theme offers an analysis of the implications of potential urban sources, closely aligned with the specific aims and objectives of the study.
	Limitations and recommendations in addressing urban air pollution	Explanations or specification	This theme investigates limitations and provides recommendations for addressing urban air pollution, highlighting the intended audience, including government and regulatory agencies, policymakers, environmental organizations, industry stakeholders, research institutions, public health agencies, international organizations, and the media. The recommendations were made to inform AQ management and regulatory decisions based on the study’s findings.
	Repetition	Methodology specification	This theme identifies and analyzes similar studies, focusing on the chosen methodology.

illustrates the thematic classes, normalized responses, and conceptual descriptions and definitions utilized throughout this study to minimize discrepancies and improve data consistency. This systematic approach enabled the identification of critical research gaps, the assessment of tools and methods used in AQ studies and the evaluation of case studies to extract meaningful insights into urban AQ trends and challenges in the region.

3. Results and Discussion

The results presented in

Table 2. Summary of the systematic review results on urban AQ in the Arabian Peninsula.

Reference ID	Spatial Coverage/Region, Country, Case Study in urban area	Methodology	Air Pollutants	Sources	Temporal Coverage	Implications/Recommendations
[43]	Oman/Muscat, Sultan Qaboos University	CALPUFF Air Pollutant Dispersion Model,	CO, NOx, CO2	Traffic emissions	2 April 2014 (24 h)	Enhanced traffic management is needed to improve student health.
[36]	United Arab Emirates	Moderate Resolution Imaging Spectroradiometer (MODIS), and Multi-Angle Implementation of Atmospheric Correction (MAIAC) Satellite Data	Aerosol Optical Depth (AOD)	Desert dust	2003–2018	Higher AOD over coastal and desert regions.
[44]	Kuwait/Kuwait City, Ali Sabah Al-Salem	Harvard Impactor Samplers	PM2.5, PM10	Anthropogenic sources	October 2017–October 2019	Regional particulate matter mitigation strategies are required.
[45]	Saudi Arabia/Al-Qurayyat	MODIS Satellite and Questionnaires	NO2, SO2, CO, AOD	Windblown dust	Instant air pollution maps	Major pollution sources include construction and dust, with minimal traffic contribution.
[46]	Saudi Arabia/Riyadh	Measurements, Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT)	Air mass transport	Dust regional emissions	Summer of 2012 (88 days)	Pollution increases linked to northwest solid winds and major regional emissions.
[34]	Kuwait/Urban Industry	Air pollutant dispersion model, American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD)	SO2, NO2	Industrial emissions	One year (2014)	Importance of hourly emission estimates for AQ assessment.
[33]	Qatar/Doha	Measurement	BTEX, NOx, O3, NH3	Traffic and urban background	29 February–31 March 2016	Vehicle emissions are a key contributor to city AQ.
[47]	Saudi Arabia/Jeddah	Positive Matrix Factorization (PMF) and Receptor Modeling	14 PAHs	Urban primary school	23 February–23 April 2013	Pollution from gasoline vehicles and industrial sources.
[48]	Saudi Arabia/Jeddah	Measurements	PAHs	Urban walkways	Jan–Feb 2020	Traffic emissions are a major source of PAHs in urban dust.
[49]	Saudi Arabia	AErosol RObotic NETwork (AERONET), Ozone Monitoring Instrument (OMI), and Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO)	Dust, Black Carbon, Aerosols	Fossil fuel and biogenic emissions	2004–2016	Aerosols are mainly from fossil fuels and biogenic emissions.
[50]	Saudi Arabia	Measurements	PM10, SO2, NO2, CO, O3	Urban background areas	Jan 2019–May 2020	The COVID-19 lockdown contributed to air pollution reduction. Traffic and industrial activities are primary contributors to urban air pollution.
[51]	Saudi Arabia/Riyadh	Questionnaires and Descriptive Statistics	CO	Traffic emissions	20–30 min survey	Promote green mobility for the renewable energy transition.
[25]	Qatar/Doha	CALINE4	NO2	Vehicle emissions	Dec 2012, Mar–Apr 2013	Traffic management is essential for improved AQ.
[52]	United Arab Emirates/Northern Emirates	MODIS and MAIAC Satellite Data	NO2, AOD	Regional emissions	1 March–30 June 2019 and 2020	The COVID-19 lockdowns could be a strategy to manage air pollution.
[53]	Saudi Arabia/Riyadh	Principal Component Analysis (PCA) and Multiple Linear Regression (MLR)	PM10 Toxicity	Soil and road dust	Dec 2019–Mar 2020, May 2020–Aug 2020	The study highlights PM10 toxicity, aiding targeted AQ policies.
[54]	Arabian Peninsula	AERONET, MODIS, and Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO)	AOD	Urban anthropogenic emissions	6–23 Aug 2013	Higher correlations during dusty periods.
[28]	Arabian Peninsula	Weather Research and Forecasting model coupled with Chemistry (WRF–CHIMERE)	PM10, AOD	Regional dust episodes	Seven dust events (2014–2017)	Extreme dust causes hazardous air and hampers PV performance by blocking light and soiling panels
[55]	Arabian Peninsula	Measurements, MODIS, and AERONET	Dust, AOD	Regional dust episodes	1 November 1 2016–31 October 2017	Dry deposition is the most effective aerosol removal mechanism.
[32]	Saudi Arabia/Riyadh	Measurements	PAH	Oil combustion emissions	Sep 2011–Sep 2012	Traffic and solid fuel burning significantly contribute to PAH levels.
[56]	Middle East to the Arabian Sea	Sample Collection, Measurements	Dust, Sr, Nd Isotopes	Surrounding land masses	13 January–10 February 2020	Dust from the Arabian Peninsula impacts pelagic waters.
[57]	Eastern Mediterranean	Aqua MODIS Satellite	AOD	Sahara and Arabian Desert dust	2000–2014	Circulation types like Sharav lows highly correlate with AOD.
[58]	Saudi Arabia	Measurement Campaigns	Total Suspended Particulates (TSP)	Semi-urban Red Sea coast	27 months	Natural and anthropogenic particulates cause frequent poor AQ.
[59]	Eastern Mediterranean	Air Mass Trajectory Models	PAHs in PM10	NE Africa and the Middle East	2011–2012	Clean marine air masses reduce PAH levels in all seasons.
[60]	Saudi Arabia/Jeddah (Red Sea Coast)	Continuous Measurements	TSP	Semi-urban and offshore sites	Sep 2015–Dec 2017	Stringent measures are needed to improve regional AQ.
[61]	Middle East/Kuwait, Dubai, Muscat	MODIS V6 Satellite	NO, CO, O3, NO2, SO2, AOD	Urban heat island emissions	Mar–Jun 2020	Lockdown reduced primary pollutant levels, lowering nighttime heat intensity.
[62]	Arabian Peninsula	MODIS V6 Satellite	Dust, Aerosols	Infrastructure activities, traffic, and industrial plants	Not specified	Dust particles dominate, with significant industrial pollution impact.
[2]	Eastern Mediterranean	Review	PM2.5	Mixed sources (TIR, biomass, and sea salt)	2015–2021	Future studies are needed to understand urban emission sources better.
[40]	Arabian Peninsula	WRF–Chem Model	Solar radiation, Aerosols	Land conversion and Urbanization	May–Aug 2015, Jan–Feb 2016	Future work should test the aerosol treatment on DNI predictions.
[27]	Saudi Arabia/Dhahran	Continuous Measurements	NOx, NO, NO2	Traffic and meteorology	May–Jul 2015	Influenced by photochemistry and meteorology, with traffic as the common source.
[63]	Saudi Arabia/Makkah	Glass Fiber Filters	PAHs in TSP, PM10, PM2.5	Traffic, industry, and waste combustion	High-volume samplers, 24 h periods	Further measurements are needed across more locations.
[64]	Saudi Arabia/Makkah	AQ Model (AirQ2.2.3) and Monitoring	PM10	Dust resuspension, road traffic	Mar 2012–Feb 2013	The approach highlights air pollutant risks to human health despite uncertainties.
[65]	Iraq/Baghdad	Gas Chromatography–Mass Spectrometry (GC–MS) and Chemical Mass Balance (CMB) Model	PM2.5	Gasoline, diesel generators, and wood/oil combustion	Sep 2012–Sep 2013	More studies are needed to profile fuels used in Baghdad for accurate PM2.5 source identification.
[66]	Middle East/Qatar	Regional Emission Models	Coarse particles PM2.5–10	Non-exhaust traffic	Qatar region	Barren land emissions are a major source of coarse particles.
[67]	Qatar/Doha	Molecular Markers, PMF, Conditional Probability Function (CPF), Potential Source Contribution Function (PSCF)	PM2.5, PM10	Secondary aerosols and vehicle emissions	May–Dec 2015	Regional collaboration is needed for better transboundary pollution control.
[31]	Qatar/Doha	Molecular Markers, PMF, CPF, and PSCF	PM2.5, PM2.5–10	Biogenic oil refinery emissions	May–Dec 2015	High local contributions highlight the opportunity to reduce population exposure.
[68]	Arabian Gulf Region	Aerosol Collection	Dust aerosols	Petrochemical industry and urbanized areas	Aug–Sep 2004	Aerosol burden impacts AQ, reaching unhealthy PM levels.
[39]	Arabian Peninsula	Satellite and measurements	Particles 5–1000 nm	Deserts and Tokar Gap winds	May–Jun 2013	Further studies are recommended to understand dust variations over the Arabian Peninsula.
[69]	Arabian Peninsula	AERONET V3 Satellite	AOD	Dust from the Sahara and Arabian Desert	2008–2017	Urban/industrial emissions are key contributors to regional aerosols.
[70]	Arabian Deserts	Dust Sampling	PM2.5, PM10	Dust episodes	Summer, Fall 2012	Aerosols from dust events pose minimal additional health risks.
[71]	Saudi Arabia/Riyadh	Dust Sampling	Dust characteristics	Urban construction activities	Jan–Mar	High dust deposition rates near construction sites and in Eastern Riyadh.
[72]	Oman/Sohar	Differential Optical Absorption Spectroscopy (DOAS)	PM2.5, O3, NO2, SO2	Vehicle emissions	Nov 2014–Feb 2015	Policy recommendations for air pollution mitigation are needed.
[30]	Saudi Arabia/Rabigh	Enrichment Factor (EF) and PMF	PM2.5	Soil, fossil fuel, and industry emissions	6 May–17 June 2013	Comprehensive research is needed for sustainable AQ guidelines.
[73]	Saudi Arabia/Makkah	EF, PMF, and Clustering	PM10	Natural sources and vehicle emissions	Feb 2013–Jul 2014	Identification of natural vs. human-made pollution sources is needed.
[74]	Saudi Arabia/Jeddah	HYSPLIT	Dust transport	Long-range transportation	Aug 2011–Jul 2012	Regional collaboration for better AQ control is necessary.
[75]	Middle East/Qatar	Observations and WRF–Chem	Mineral dust, anthropogenic aerosols	Dust sources and petrochemical plants	2016	The 2016 summer heatwaves were primarily influenced by mineral dust and fossil fuel sources.
[76]	Qatar/Dukhan	Measurements and HYSPLIT	PM10	Regional emissions	Jan–Dec 2016	High levels of regional PM10 were detected across the study area.
[77]	Qatar/Doha	PCA, Positive Matrix Factorization (PMF), and Long-Range Transport (LRT)	PM2.5	Natural traffic sources	2016	The study underscores the importance of local source contributions to PM2.5 levels.
[28]	Qatar/Doha	Mesoscale Model Version 5 (MM5) and Community Multiscale AQ Model (CMAQ)	SO2, PM2.5, PM10	Natural and urban emissions	18 July–5 August 2012	AQ management strategies are essential for managing pollution levels.
[78]	Jordan/Amman	Observations and PMF	PM10, PM2.5	Natural sources and vehicle emissions	May 2018-March 2019	Transboundary pollution analysis was critical for regional AQ improvement.
[79]	Bahrain	Site measurements	SO2, NO2, O3, CO, PM10, PM2.5	Industrial zone	January 2012–August 2012	Dust storms increased PM10 pollution.
[35]	Gulf Cooperation Council (GCC)	Critical review	CO2, CO, PM, metals, NOx, O3, SO2, VOCs, PAHs	Cement, metal, stone cutting industries, and transportation	The early 2000s	Significant pollution is linked to cement, metal, stone cutting, and transportation industries.
[80]	Middle East	Review	Particulate matter (PM)	Traffic, industrial emissions, and Arabian dust transport	2015	PM from major building activities.
[81]	West Asia/Saudi Arabia	Remote sensing	PM2.5	Urbanization	2005–2016	Urban strategies and governance are needed to reduce PM2.5 in urban construction areas.
[82]	Kuwait	Monitoring stations	CO, NOx, O3, SO2	Urban, suburban, and rural	2007–2010	Photochemical reactions led to an inverse relationship between background concentrations.
[100]	Iraq/Baghdad City	Ground measurements and satellite-based estimates	PM2.5, AOD	Dust storms, high-density traffic	January 2022–December 2022	Public health interventions during periods of high pollution
[101]	Kuwait/Al-Shuwaikh City and Al-Fahaheel City	Random forest regression	NO2/NOx	vehicular sources	2004–2014	Extreme heat and strong solar radiation significantly impact urban air quality
[102]	Qatar/Doha	TROPOMI satellite data	NO2	FIFA Football World Cup event	May 2018–December 2023	Meteorological factors strongly influence urban air quality.
[103]	Iraq/Tymar City	Machine learning, Random Forest, and regression models	SO2, NO2	Industrial and residential sources	August–September 202 and February–Marc 2022	Model inputs can affect outputs and should be used carefully, especially for harmful pollutants
[104]	Iraq/Fallujah City	Ground measurements	TSP, PM2.5, PM10, SO2, NO2	Industrial and residential sources	Winter and Summer seasons of 2022	Rising electricity demand and private generators contribute to air pollution.
[105]	UAE/Abu Dhabi	Autoregressive Integrated Moving Average (ARIMA) models and Ground measurements	PM2.5, PM10, NO2	Urban areas of Abu Dhabi	2015–2023	The study reveals air pollution trends, highlighting the need for regulation to meet Abu Dhabi’s 2030 vision
[106]	Gulf of Oman	Particle samples	TSP	aeolian dust	February 2022	The sediment resuspension and lateral transport under eddy-topography interaction contribute to the identified pollution level
[107]	UAE/Abu Dhabi	Ground measurements, Machine learning, Random Forest, and regression models	PM2.5, PM10	Urban areas of Abu Dhabi	January 2018–December 2022	Particulate matter pollution poses significant health and environmental risks in urban areas
[108]	Qatar/Doha	Review	PM, CO2, NOx	Vehicle exhausts, industrial processes and natural phenomena	2013 and early 2024	The study underscores the urgent need to revise environmental health policies
[109]	Iraq/Karbala, Baghdad, Sulaymaniyah Cities	Ground measurements	PM2.5	Urban emissions	February 2020–August 2021	Future studies are recommended to explore the complex interplay between air quality and disease transmission
[110]	UAE	WRF-Chem and TROPOMI satellite data	O3, CO, and NO2	Urban emissions	June and December 2022	This study helps address biases and enhance understanding of regional air quality dynamics
[111]	Middle East	Ground measurements and HYSPLIT trajectory model	PM2.5, PM10	Dust storms	May 2022	Air pollution is strongly influenced by atmospheric conditions, topography, and transport routes
[112]	Iraq/Great Husseiny Park	Ground measurements	PM2.5, PM10	Urban emissions	January and October 2016	The study highlighted that trees and plants effectively reduce air pollution.
[113]	Saudi Arabia/eastern region	HYSPLIT trajectory model	PM10	Dust storms	January–March 2022	Planting trees effectively mitigates air pollution
[114]	UAE/Sharjah City	HYSPLIT trajectory model	PM2.5, PM10	traffic, sea salt, fugitive dust	October 2017–September 2018	Mineral dust dominates and impacts air pollution in the region
[115]	Iraq/Baghdad and Mosul Cities	Ground measurements	PM2.5, PM10	Desert particles	January–December 2022	Desert areas affect air quality
[116]	Qatar/Doha	Ground measurements	PM2.5	Traffic	October 2023	Planting trees effectively mitigates air pollution

summarize the systematic review, while those in

Table 3. Summary of meta-analysis results on urban AQ in the Arabian Peninsula.

Current state of the art and significant research gaps	Pollutants	Pollutants	CO	CO2	Dust	Nox/NO/NO2	O3	PAHs	PM10	PM2.5	SO2	VOCs
		%	6.00%	1.90%	23.10%	17.20%	5.40%	5.60%	12.00%	17.60%	9.30%	1.90%
	Sources	Source	Natural dust	Industrial emissions	Traffic emissions	Fossil fuel combustion	Other sources
		%	24%	27.00%	19.00%	22.00%	8.00%
	Studied areas	Region/Country	Region (Arabian Peninsula) a	Saudi Arabi	Qatar	United Arab Emirates	Kuwait	Oman	Iraq	Jordan	Bahrain
		Counts	16	20	12	7	4	3	7	1	1
	Publications	Year	Early 2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015	2014	2013
		Counts	7	10	14	11	9	4	9	13	7	6	8	3	3
Tools and experimental design	Air quality models	Type	AERMOD	CALPUFF	CALINE4	WRF-Chem
		Counts	1	2	1	3
	Monitoring devices	Type	Mobile	Fixed	Combined (mobile and fixed)
		%	16.80%	80%	3.20%
	Calibration	Type	Station Reference	Self-Reference	Not Specified
		%	13.30%	27.60%	59.10%
	Sampling methods	Type	Grab sampling	Integrated sampling	Continuous monitoring
		%	19%	34.00%	47.00%
	Methodologies	Type	Measurements and sampling	Satellite data and remote sensing	Air quality dispersion models	Statistical methods	Trajectory models	Questionnaires and surveys	Critical reviews	Other
		%	28.00%	24.00%	16.60%	19.00%	6.00%	3.00%	1.50%	1.90%

represent the meta-analysis of urban AQ in the Arabian Peninsula based on the 71 papers that met the criteria outlined in the methodology section.

3.1. Current State of the Art and Significant Research Gaps

3.1.1. Most Studied Air Pollutants

During our review and meta-analysis, we compiled air pollutant data (Figure 4a) from studies published between 2013 and early (June) 2025 (Figure 4b). The analysis highlighted AQ concerns in the Arabian Peninsula. These results indicated that dust, NO_x, and particulate matter (PM) remain the most studied pollutants in the Arabian Peninsula, reflecting ongoing concerns regarding AQ management.

Dust emerged as the most frequently reported pollutant with 16 occurrences (23.1%), reflecting the region’s arid environment and frequent dust storms. Studies such as Kaku et al. [68] and Shaltout et al. [75] confirm that mineral dust significantly influences AQ, particularly during extreme weather events that increase atmospheric aerosol concentrations. The persistence of dust as a primary air pollutant has been further emphasized by Modaihsh and Mahjou [71], who documented high deposition rates in urban areas, particularly near construction zones. Nitrogen oxides (NO_x/NO/NO₂), with twelve occurrences (17.2%), represent another major pollutant. Gasmi et al. [27] identified traffic emissions as a dominant source of NO_x, pointing to the role of vehicular congestion in pollutant accumulation. Additionally, Omidvarborna et al. [35] highlighted NO_x as a key contributor to air pollution across the region, reinforcing its significance in regional studies. Particulate matter (PM_2.5 and PM₁₀) was also frequently studied, with twelve occurrences (17.6%) and nine occurrences (12%), respectively. The widespread occurrence of particulate matter across the reviewed studies indicates that it is a pollutant of growing concern, particularly given its association with both natural sources, such as dust storms, and anthropogenic emissions from industrial activities and traffic. The focus on PM in AQ research reflects its complex behavior in the atmosphere, its ability to interact with other pollutants [30], and its contribution to regional haze and visibility reduction [83].

Other pollutants, including sulfur dioxide (SO₂) with seven occurrences (9.3%), carbon monoxide (CO) with four occurrences (6%), and ozone (O₃) with four occurrences (5.4%), polycyclic aromatic hydrocarbons (PAHs) with four occurrences (5.6%), and volatile organic compounds (VOCs) and carbon dioxide (CO₂) with 1 occurrence (1.9%) each, were reported less frequently. The lower frequency of VOCs and CO₂ in the reviewed studies suggests that while these pollutants contribute to atmospheric chemistry, they may not have been a primary focus of AQ assessments in the region. Nevertheless, the consistency of findings across different studies underscored the importance of continued monitoring and mitigation as essential components of AQ management in the Arabian Peninsula.

3.1.2. Potential Emission Sources of Air Pollutants and Their Implication for Urban AQ

This study highlighted the significant influence of various urban sources on AQ outcomes in the Arabian Peninsula. The analysis of the potential emission sources of air pollutants in the Arabian Peninsula, as presented in Figure 5a, revealed several key findings. Industrial emissions are the most frequent source, with 19 occurrences (27%), underscoring the significant role of industrial activities such as petrochemical plants, oil refineries, and cement industries in contributing to regional air pollution. These findings reflect the need for enhanced regulatory measures and pollution control technologies to mitigate the impact of industrial activities on the region’s AQ [32,63,68,80].

Natural dust sources also play a major role, with 17 occurrences (24%). This reflects the significant influence of desert dust from sources like the Arabian Desert. The prevalence of natural dust highlights the region’s unique climatic and geographical factors that exacerbate air pollution, particularly during dust storms [2,36,45,54]. Fossil fuel combustion follows closely with 16 occurrences (22%). This category includes emissions from urban activities and oil refineries, indicating that energy production and transportation are substantial sources of pollutants and require comprehensive strategies to mitigate their impact [32,49,61]. These findings suggested that reducing fossil fuel use and improving energy efficiency are vital for mitigating air pollution.

Traffic emissions are reported 13 times (19%), illustrating their contribution to urban air pollution [30,49,70,72,80]. Other sources, including second air pollutants, marine air masses, biogenic sources, and unidentified sources account for six occurrences (8%) [67,76]. The distribution of potential emissions by country is presented in Figure 5b.

3.1.3. Most Studied Areas in the Arabian Peninsula

Among the 71 reviewed studies, Saudi Arabia emerges as the most extensively studied country, with twenty occurrences, followed by Qatar with twelve, the UAE and Iraq with seven each, Kuwait with four, Oman with three, and the broader Arabian Peninsula region with sixteen, as illustrated in Figure 6.

The importance of Saudi Arabia in these studies reflects its critical role in regional urban AQ research, partly due to its surface area size, its diverse geographic and climatic conditions [77], and its significant industrial activities. These factors contribute to a complex pollution landscape, with key sources such as oil refineries [51], petrochemical plants, and heavy traffic emissions concentrated in major cities [46] and industrial hubs [75]. The focus on Saudi Arabia underscores its importance in understanding air pollution within the Arabian Peninsula and highlights the necessity of targeted interventions in these high-impact areas to improve AQ across the region. In contrast, other countries such as Qatar, the UAE, Kuwait, and Oman are less frequently studied despite being home to considerable industrial [29] and urban development [84], which contribute to air pollution. The relatively lower number of studies in these countries suggests that while they might share similar pollution challenges as those of Saudi Arabia, they have not received equivalent research attention. This disparity points to potential research gaps that need to be addressed to ensure an inclusive understanding of AQ across the Arabian Peninsula. By expanding research efforts in these underrepresented areas, we can gain a more complete picture of regional air pollution dynamics, which is essential for developing effective AQ management strategies. The Arabian Peninsula, with 15 occurrences, draws attention due to its unique environmental and atmospheric conditions, offering valuable insights into regional AQ studies. Focusing on these broader regions is valuable for identifying general trends and common challenges, but it may overlook the unique conditions and specific pollution sources in individual countries. In addition, countries like Iraq, Jordan, and Bahrain, each with only one occurrence, are notably underrepresented in the literature. This lack of attention limits our understanding of the full extent of air pollution issues in these areas and hampers efforts to implement region-wide solutions.

The findings from this review highlighted the need for a more balanced and comprehensive approach to urban AQ studies across the Arabian Peninsula. Expanding research efforts to cover less-studied areas will enable the development of a more holistic understanding of air pollution in the region, ultimately leading to better-informed policies and more effective interventions. The overall distribution of related studies across the reviewed countries is presented in Table 2, further emphasizing the current research landscape and the areas in need of greater focus.

3.1.4. AQ Monitoring Devices and Models (Types and Most Used)

This study revealed insights into the types of AQ monitoring devices (Figure 7a) and models (Figure 7b) used in the Arabian Peninsula. Among the studies that used measurement and sampling methods, the results showed that fixed monitoring stations are predominantly used, accounting for 16 occurrences (80%). This prevalence highlights the reliance on stationary devices for continuous and long-term AQ assessments across the region. Mobile monitoring devices are less frequently used with three occurrences (16.8%), suggesting that while adopting these more flexible and location-specific tools is possible, they are not as widespread. The combination of mobile and fixed monitoring approaches is the least common, observed only in one occurrence (3.2%), indicating that integrated strategies that leverage the strengths of both methods are still in their infancy within the region. The findings showed a limited use of AQ models in urban AQ studies. Models like CALPUFF [43], AERMOD [34], WRF, WRF–CHIMERE [28,40], WRF–Chem [75], and MM5-CMAQ [28] have been utilized in the region for predicting how pollutants spread under different environmental conditions. The AERMOD model, which is widely recognized for its application in industrial source modeling [85,86], appears only once, suggesting that this type of modeling is not a primary focus in the Arabian Peninsula. Similarly, CALINE4, designed for predicting pollutant dispersion near roadways [25], also appears only once, indicating limited exploration of traffic-related pollution using this model. The CALPUFF model, which is suitable for simulating the long-range transport of pollutants [86,87], is slightly more common with two occurrences, reflecting some interest in understanding pollutant dispersion over larger areas. WRF–Chem, a sophisticated model that couples weather forecasting with chemical transport modeling [75,88], is also observed three times, pointing to a growing but limited use of advanced atmospheric modeling techniques in the region. Overall, these results suggested that while fixed monitoring stations dominate AQ assessment in the Arabian Peninsula, the use of advanced AQ models remains relatively underdeveloped.

3.2. Essential Tools and Elements in Material and Experimental Design

The results presented in Figure 8a highlight the overall information about the methodologies currently used for assessing urban AQ in the Arabian Peninsula.

Measurements and sampling methods emerge as the most frequently employed methodology, with 20 occurrences (28%). This category encompasses a broad range of general measurement techniques [32,33,46,50,55,89] and sample collection methods [44,56,58,70], focusing on pollutants such as dust, aerosols, and particulate matter. It also includes specific dust or aerosol sampling techniques, essential for directly assessing the environmental concentration and distribution of pollutants. The prominence of this methodology highlights the importance of on-the-ground data collection in understanding AQ, as it provides the empirical evidence needed for accurate analysis and modeling. Satellite data and remote sensing follow, with 17 occurrences (24%). This methodology involves the use of satellite data and remote sensing techniques, such as MODIS [36,45,52,54], AERONET [49,54,69], CALIPSO [54], and OMI [49], which allow for large-scale monitoring of AQ over vast geographic areas. Satellite measurements in the Arabian Peninsula provide critical insights into the spatial distribution of pollutants, especially in regions that are difficult to access for ground-based measurements [25,52,57,61]. The high frequency of this method reflects its importance in providing comprehensive and continuous data that complement ground-based observations. Statistical methods, with 13 occurrences (19%), include various receptor modeling techniques such as Positive Matrix Factorization (PMF) [30,47,67,77,78], Conditional Probability Function (CPF) [31], and Chemical Mass Balance (CMB) [65], as well as Principal Component Analysis (PCA) [53], Multiple Linear Regression (MLR) [53], and other descriptive approaches [30,31,65,72]. These techniques are essential for identifying pollution sources, understanding pollutant behavior, and making predictions based on the collected data. AQ and dispersion models appear with twelve occurrences (16.6%), while trajectory models appear with four occurrences (6%), involving the analysis of air mass movements using tools like HYSPLIT and other air mass trajectory models [46,74,76]. These models help track the origin and movement of air pollutants, which is essential for understanding long-range transport and identifying the sources of contaminants over time. Questionnaires and surveys with two occurrences (3%), while critical reviews [35] and other specialized instruments [2] appear with one occurrence (1.5% and 1.9%, respectively). Other specialized instruments, such as Gas Chromatography–Mass Spectrometry (GC–MS) [65] and fast-response spectrometers [67], are also used for more targeted and detailed chemical analyses of urban air pollutants in the Arabian Peninsula.

A noteworthy development is the expansion of regional initiatives led by spearheaded by governmental and institutional bodies such as the Royal Commission for Riyadh City (RCRC) (Add Ref), the National Center for Meteorology (NCM) UAE (Add Ref), and Kingdom of Saudi Arabia (Add Ref), and the Environment Abu Dhabi (EAD) (Add Ref). These institutions have made substantial contributions by establishing real-time monitoring networks, developing AQ forecasting systems, launching public-facing applications (e.g., the RCRC AQ app), (Ref App), and conducting comprehensive assessments of urban air pollution. Although these outputs are not peer-reviewed in the traditional academic sense therefore, excluded from the core meta-analysis, they play a vital role in shaping the region’s AQ landscape. They contribute essential data, support evidence-based policy decisions, and foster greater public engagement with environmental issues. Future work would benefit from closer integration of institutional data sources with peer-reviewed research to produce a more comprehensive and policy-relevant understanding of AQ trends and challenges across the Arabian Peninsula.

It is also essential to mention that during our meta-analysis, we did not only focus on the methodologies used but also considered specific critical elements related to the overall methodology in each paper. These include:

Spatial and Temporal Coverage: The results presented in Table 2 highlight varying levels of spatial and temporal coverage across all consulted studies. While some focus on specific urban areas [43,46,67,90] provides detailed local insights into urban status based on AQ, others adopt a broader regional approach, capturing a wide range of urban and peri-urban environments [28,57,58,59,62,69]. The temporal coverage also varies, with some studies providing long-term monitoring data spanning several years [2,30,57] while others focus on short-term campaigns lasting a few months at most [51,56,67,68,71]. This diversity in coverage is crucial for capturing the dynamics of urban AQ across different scales and time frames.

Resolution of the Modeling Domain: The resolution of the modeling domain in the reviewed studies varies significantly, ranging from fine-scale, especially for AERMOD [34] and CALPUFF [43]. High-resolution models like WRF–Chem, as utilized by Fountoukis et al. [40] and Shaltout et al. [75], focused on specific urban areas and significantly contributed to urban AQ studies. It is essential to mention that, in AQ modeling studies [19,85], the choice of a good model [21,39] is essential for decision making and environmental management strategies [86,91].

Calibration and Accuracy of Monitoring Devices: Among the studies that used measurement and sampling methods, twelve occurrences (59.1%) did not mention the devices’ calibration methods while six occurrences (27.6%) used self-calibration and two occurrences (13.3%) used station calibration methods (Figure 8b). However, some studies provided protocols for sampling and sampling techniques, including grab sampling with four occurrences (19%), integrated sampling with seven occurrences (34%), and continuous monitoring with nine occurrences (47%) (Figure 8c), especially for satellite data and remote sensing, which typically include specific resolution and instrument calibration protocols. Monitoring device calibration is a critical step in ensuring data accuracy and reliability [92,93,94]. This study emphasizes the importance of regular calibration using reference-grade instruments or established calibration protocols [92], which is essential for maintaining the validity of data collected from low-cost sensors prone to drift over time. This need for regular calibration was also identified as a gap in the literature reviewed here.

3.3. Analysis of Case Studies and Their Resulting Outcomes

In each paper, we investigated the limitations and recommendations highlighted by the authors for addressing urban air pollution, summarized in Table 2. Most of these recommendations were made to inform AQ management and regulatory decisions. Several limitations are identified across the studies, including the scarcity of long-term data [72]. Multiple studies emphasized the importance of expanding monitoring efforts [30] to include not only well-developed urban centers but also peripheral and rural areas [80,81], where data scarcity has led to gaps in understanding the true extent of air pollution [43,44]. Further recommendations from studies highlighted that future research on urban AQ should prioritize the development of more monitoring networks [35] that combine ground-based [43] and remote sensing data [36]. A review also highlighted the necessity of standardizing methodologies and calibration procedures across studies to ensure the reliability and comparability of AQ data [39]. Another study also highlighted the need for innovative urban AQ techniques to address emerging challenges [76]. In addition, a need for advanced modeling techniques to more accurately capture the complexities of pollutant dispersion in urban environments, as evidenced by Al-Fadhli et al. [34] and Fountoukis et al. [40], was recommended. Future studies should focus on integrating health impact assessments [43] to better understand the public health implications of air pollution [53]. Policymakers were encouraged to adopt a multi-faceted approach that includes stricter emission controls [27], the promotion of cleaner technologies [63], and the implementation of sustainable urban planning practices [69] to mitigate the adverse effects of air pollution in the Arabian Peninsula. The implications of these findings extended to policy-making, where there is a pressing need for stricter regulation of industrial emissions and traffic-related pollution [36,67].

The review analysis also underscored the importance of public awareness and education in addressing AQ issues. Increasing community engagement and educating the public about the health risks associated with air pollution can lead to more significant support for AQ management initiatives and encourage behavioral changes that contribute to reducing pollution levels. Studies suggest that public participation in AQ monitoring and management could be a valuable tool in enhancing the effectiveness of these efforts [43,44]. The review further emphasizes integrating AQ data with other environmental and socioeconomic factors to develop more comprehensive urban planning strategies for transportation management, public health initiatives, industrial growth, and population density [44,67]. Another significant recommendation from the review analysis is the need for enhanced cross-border collaboration among countries in the Arabian Peninsula. Air pollution does not respect national boundaries, and transboundary pollution is a critical issue in the region, particularly due to the movement of dust [49] and other pollutants across borders [36]. Collaborative research, monitoring, and policy-making efforts can help address these shared challenges more effectively. Establishing regional frameworks for AQ management and data sharing could lead to more coordinated and impactful actions to reduce pollution levels across the Arabian Peninsula.

Compared to other global regions where urban AQ has been more extensively studied, such as South Asia, North Africa, and Europe, the Arabian Peninsula exhibits a distinct and underexplored set of environmental and anthropogenic factors. In South Asia, particularly in countries like India and Bangladesh, severe urban air pollution is primarily attributed to dense populations, coal-based energy production, the extensive use of biomass for cooking, and high vehicular emissions [95,96,97]. Seasonal variations in pollution levels are also influenced by agricultural burning and the South Asian monsoon system, which affect pollutant dispersion. In North Africa, urban centers such as Cairo and Algiers face high pollutant concentrations from traffic congestion, industrial zones, and increasing energy demand, compounded by Saharan dust intrusions [1,70,98]. Although North Africa shares some climatic features with the Arabian Peninsula, differences in urban planning, population density, and emission sources create distinct air quality dynamics. In contrast, while grappling with air pollution from transportation, industrial activity, and domestic heating, European cities benefit from comprehensive regulatory frameworks like the EU Ambient Air Quality Directives and more advanced air quality monitoring systems [99]. Efforts to transition to cleaner energy and enforce emission limits have led to measurable improvements in AQ across many European urban areas [99].

4. Concluding Remarks

In this paper, we performed a systematic review and meta-analysis of urban AQ studies to address the current state of the art, identify significant gaps, evaluate essential tools and elements in materials and experimental design, and analyze case studies and their outcomes in the Arabian Peninsula. A summary is provided below:

Current state of the art and significant research gaps in urban AQ research: (1) The results revealed a consistent pattern of pollution sources and impacts, with anthropogenic sources, particularly industrial emissions, traffic emissions, fossil fuel combustion, and natural dust being the most significant contributors to poor AQ. (2) The results highlighted that the Arabian Peninsula’s unique geographical features, such as vast desert areas, contribute to natural dust emissions, a significant component of PM₁₀ and PM_2.5 in the region. (3) While current methodologies provide valuable insights, there is a clear need for more comprehensive monitoring networks and improved modeling techniques to better understand and address the complexities of urban air pollution in the region. (4) The findings provided a comprehensive literature overview, highlighting extensive research on urban air pollution in Saudi Arabia. However, urban AQ studies in Qatar, the UAE, Kuwait, Oman, Iraq, Jordan, and Bahrain remain limited, indicating a need for further research in these countries. (5) Furthermore, the review identifies gaps in the existing research, particularly regarding the study of certain pollutants and sources. For instance, VOCs and PAHs, linked to severe health effects, are less frequently studied in the region despite their potential presence due to industrial activities and vehicular emissions. Similarly, the contribution of emerging sources, such as construction activities and waste burning, is not well-documented, indicating a need for future research to address these gaps.

Essential tools and elements in material and experimental design: (1) The findings highlighted significant limitations in the current body of research, particularly concerning the uneven spatial and temporal coverage of AQ monitoring across the Arabian Peninsula. This inconsistency hinders comprehensive conclusions about AQ trends in the region. (2) The variability in the accuracy and calibration of monitoring devices across studies poses challenges, leading to potential data inconsistencies. These issues underscore the urgent need for standardized methodologies and calibration procedures to ensure the reliability and comparability of AQ data. (3) Future research should prioritize the development of expanded monitoring networks that integrate ground-based and remote sensing data to overcome current limitations. Furthermore, incorporating health impact assessments in studies will also be vital for understanding the public health implications of air pollution.

Case studies and their outcomes: (1) The review advocates for a multidisciplinary approach that integrates environmental science, public health, urban planning, transportation networks, industry, and policymaking to address the complex interactions between air pollution, human health, and urban development in the Arabian Peninsula. It highlights the need for targeted interventions to reduce emissions from the critical sources identified. (2) The review suggests that future research should focus on the long-term impacts of air pollution on public health and the long-range transboundary transport of dust pollution in the Arabian Peninsula. (3) The review highlights the importance of raising public awareness about the health risks associated with air pollution and the need for community engagement in AQ management efforts. (4) The transboundary nature of air pollution, driven by atmospheric circulations that transport pollutants across borders, requires regional cooperation, collaborative policies, data sharing, and cross-border monitoring systems to effectively address this challenge. This would provide valuable insights into the long-term health risks associated with urban air pollution in the region and inform the development of more effective public health interventions.

We acknowledge several limitations in this review of urban AQ research in the Arabian Peninsula. One major limitation is the scarcity of publicly available data, unlike in the European Union (EU), where real-time data from government monitoring stations is freely accessible (EEA Air Quality Index (https://airindex.eea.europa.eu/AQI/index.html accessed on 28 June 2025)). Another limitation is the inclusion of only English-language publications, which may have introduced bias by excluding many local reports not published in English. While we aimed for comprehensive coverage, some relevant studies may have been inadvertently excluded, particularly when applying selection criteria (4) to (7), potentially omitting literature that could have provided additional insights. Nevertheless, we believe the extracted data offers a representative overview of the current research on urban AQ in the Arabian Peninsula. Despite these limitations, our findings reflect prevailing knowledge in the field and provide a solid foundation for understanding the region’s challenges and developments related to urban AQ. In addition, we recommend awareness campaigns and practical initiatives to be implemented in the region to increase public access to AQ information. For instance, mobile applications and web-based tools can be developed to inform the public about real-time AQ conditions and forecasts.