Spatio-Temporal Variation Characteristics of PM2.5 in the Beijing–Tianjin–Hebei Region, China, from 2013 to 2018

Air pollution, including particulate matter (PM2.5) pollution, is extremely harmful to the environment as well as human health. The Beijing–Tianjin–Hebei (BTH) Region has experienced heavy PM2.5 pollution within China. In this study, a six-year time series (January 2013–December 2018) of PM2.5 mass concentration data from 102 air quality monitoring stations were studied to understand the spatio-temporal variation characteristics of the BTH region. The average annual PM2.5 mass concentration in the BTH region decreased from 98.9 μg/m3 in 2013 to 64.9 μg/m3 in 2017. Therefore, China has achieved its Air Pollution Prevention and Control Plan goal of reducing the concentration of fine particulate matter in the BTH region by 25% by 2017. The PM2.5 pollution in BTH plain areas showed a more significant change than mountains areas, with the highest PM2.5 mass concentration in winter and the lowest in summer. The results of spatial autocorrelation and cluster analyses showed that the PM2.5 mass concentration in the BTH region from 2013–2018 showed a significant spatial agglomeration, and that spatial distribution characteristics were high in the south and low in the north. Changes in PM2.5 mass concentration in the BTH region were affected by both socio-economic factors and meteorological factors. Our results can provide a point of reference for making PM2.5 pollution control decisions.


Detection Indices (X) The Interpretation of Detection Indices
Sown Area of Farm /hectare The sown area of farm crops refers to the area actually sown or transplanted with crops. Whether planted on arable land or on non-arable land, they are included in the sown area of farm crops.
Urban green area /hectare Urban green area refers to the area of land that can be used for greening, excluding roof greening, vertical greening, and land covered with soil of less than 2 m depth. This includes six categories: public green spaces, residential green spaces, unit attached green spaces, protective green spaces, production green spaces, and scenic forest lands.
Gross Domestic Product /100 million yuan Gross Domestic Product (GDP) refers to the final results of the production activities of all resident units over a certain period of time. GDP is equal to the sum of the added value of each industry. Gross Domestic Product of Secondary Industry/100 million yuan The sum of the gross national product of the secondary industry. The secondary industry refers to industries (including extractive industries, manufacturing, tap water, electricity, steam, hot water, gas) and construction. Relative humidity represents the ratio of the absolute humidity in the air to the saturated absolute humidity at the same temperature and pressure.  Urban functions and spatial layout should be optimized, the population size should be reasonably controlled, and motor vehicle ownership should be strictly controlled.
Enhancing the guarantee of clean energy supply, realizing the gasification of electric power production, promoting "coal reduction and coal replacement" in urban-rural fringe and rural areas, promoting coal reduction in suburban counties, renovating small-scale pollution enterprises, building ecological industrial parks and promoting clean production.

Regulations on the Prevention and Control of Air Pollution in Beijing
Establish and improve the working mechanism of government-led, regional linkage, unit governance, participation of the whole people and social supervision; increase the coverage of greening, expand the area of water area, and carry out research on meteorological conditions of atmospheric pollution; prohibit the construction and expansion of facilities burning coal, heavy oil and residue; and implement clean energy transformation of coal-fired heating facilities in remote suburbs within the prescribed time limit. People's governments at all levels should strengthen publicity and popularization of environmental protection, encourage grassroots mass self-governing organizations, social organizations, and environmental protection volunteers to carry out publicity on environmental protection laws and regulations and environmental protection knowledge and create a good atmosphere for protecting the environment. People's governments at all levels should strengthen the protection of the agricultural environment, strengthen the monitoring and early warning of agricultural pollution sources, coordinate the relevant departments to take measures to prevent and control soil pollution and ecological imbalances such as land desertification, salinization, barrenness, rocky desertification, vegetation destruction, soil erosion and extinction of provenances.

Regulations on Prevention and Control of Air Pollution in Tianjin
Carry out meticulous grid management of air pollution prevention and control, and prohibit the use of high-polluting fuels such as coal and heavy oil, residue and petroleum coke in new, rebuilt and expanded projects in high-polluting fuel no-combustion zones. It is forbidden to incinerate defoliated leaves, straws and withered grass in the open air to produce smoke and dust pollution. Construction projects, house demolition projects, and other construction sites should adopt measures to prevent dust pollution, such as setting up the enclosure, sheathing, road hardening, spraying and so on.

Standing
Committee of the Twelfth National People's Congress August 29, 2015 Law of the People's Republic of China on the prevention and control of air pollution(2015 revision) Strengthen the comprehensive prevention and control of atmospheric pollution, such as coal combustion, industry, motor vehicles, ships, dust and agriculture, promote joint prevention and control of regional atmospheric pollution, and implement coordinated control of atmospheric pollutants such as particulate matter, sulfur dioxide, nitrogen oxides, volatile organic compounds, ammonia and greenhouse gases. Adjust the energy structure, promote the production and use of clean energy; optimize the use of coal, promote clean and efficient use of coal, gradually reduce the proportion of coal in primary energy consumption, reduce the emission of air pollutants in the process of coal production, use and conversion.

Regulations on Prevention and Control of Air Pollution in Hebei Province
No new facilities for burning highly polluting fuels such as coal, heavy oil and residue shall be built in the no-combustion zone. The existing facilities for burning highly polluting fuels should be converted to clean energy within a time limit. High-polluting fuel facilities not replaced by clean energy should be equipped with advanced desulfurization, denitrification and dust removal devices or other measures to control the emission of sulfur dioxide, nitrogen oxides, and smoke and dust. If the standards for the discharge of atmospheric pollutants have not yet been met, the use shall be discontinued. At the end of October of the same year, the government increased its capacity to eliminate excess production and completed the work of banning illegal "small scattered and dirty" enterprises. At the end of October, the construction of the "forbidden coal area" was completed. Cement and foundry industries continue to implement peak staggering production in an all-round way. The port is prohibited from receiving coal transported by diesel trucks. Open-air incineration of straw, litter, and garbage is forbidden in all respects. The key remediation areas are Beijing-Tianjin-Hebei and its surrounding areas, and the Yangtze River Delta region. Optimize the industrial layout, increase the adjustment of regional industrial layout, accelerate the relocation or closure of heavy polluting enterprises in urban built-up areas, and comprehensively carry out the "disintegration" enterprises and cluster comprehensive remediation actions. Carry out comprehensive rectification of coal-fired boilers, accelerate the upgrading of rural "coal to electricity" power grids, and accelerate the development of clean energy and new energy. Figure S1. The map of Bohai Rim Economic Circle.