Assessment of the Safety of Children’s Outdoor Public Activity Spaces: The Case of Shanghai, China

Abstract

Children’s outdoor physical activity (PA) serves as a crucial mechanism for health development, but its safety is affected by urban space design and management. However, most existing studies focus on isolated risk factors or singular spatial typologies, which lack a comprehensive safety assessment framework. This study aims to construct a safety assessment system for children’s outdoor public activity spaces and explore safety optimization strategies. This study employs a mixed methods approach to systematically analyze 13 outdoor public activity spaces across Shanghai, utilizing NVivo 12 Plus for qualitative coding of the data. Based on the coding results, a questionnaire survey targeting parents of children under 12 years old (with a balanced gender ratio) was designed and administered, yielding 509 valid responses. A 32-indicator assessment system was finally constructed via principal component analysis (PCA). The assessment system encompasses seven dimensions: site facilities (24.0%), spatial conditions (16.1%), site management (13.5%), material conditions (13.0%), service facilities (12.8%), traffic and landscape (10.3%), and ground conditions (10.3%). This study provides a quantitative safety assessment instrument for designing child-friendly urban public activity spaces, which has important implications for improving the public health service system and promoting the construction of healthy cities in the Sustainable Development Goals.

1. Introduction

As the future of the country and the hope of the nation, the comprehensive development of children is an important foundation for realizing sustainable social progress [1]. The United Nations Convention on the Rights of the Child (UNCRC) clearly emphasizes children’s rights to a healthy life, a safe environment, and full development. It also requires governments to incorporate children’s well-being into urban development planning [2]. Globally, insufficient physical activity (PA) among children has become a serious challenge affecting their healthy growth [3]. According to the assessment results of the Global Matrix 4.0 of Report Card Grades on PA for Children and Youth, the PA levels of Chinese adolescents are generally lower than the international recommended standards, which require at least 60 min of moderate to vigorous PA per day, primarily aerobic activities [4]. Studies have shown that PA in childhood is not only related to physical health [5] and mental health [6] but also has a profound impact on brain development [7], cognitive ability [8], and social adaptability [9]. Therefore, improving the quality of children’s outdoor activities is not only an important goal of the Healthy China strategy but also a key path to achieving the Sustainable Development Goals.

A child-friendly city refers to a city, town, community, or any local government system that is committed to realizing the rights of children as stipulated in the UNCRC [10]. The concept of child-friendly cities (CFC) advocates safeguarding children’s rights and promoting their comprehensive development by optimizing the urban environment [11]. Internationally, regions like Scandinavia and Canada have accumulated rich and distinctive experiences in creating safe and inclusive CFC. They attach great importance to public space planning, game space design, high participation of children, and participation by multiple entities. For example, Sweden has developed innovative spatial measures such as play pathways and fun routes to schools to build CFC [12]. Canada has enhanced children’s outdoor activity experiences by improving public transportation systems and integrating nature into urban design [13,14]. In contrast to these practices, China’s journey in CFC construction started relatively late. There are challenges such as insufficient child participation and the need for improved facility quality [15].

The principles of CFC advocate for urban planning and design that creates safe, inclusive, accessible, and appealing environments to encourage children’s physical activities and play [16]. Against this backdrop, outdoor public activity spaces play a vital role by providing urban children with opportunities to engage in a variety of sports, interact socially, and promote physical development [17]. Based on the design principles of CFC, safe and high-quality outdoor spaces can effectively inspire and support diverse children’s physical activities. The purpose of thoughtfully planning and designing these spaces is to provide a diverse, enjoyable, and safe environment for physical activities, thereby encouraging children’s active participation in sports. Research indicates that the most common activities children engage in within these spaces are ball sports, climbing or hanging, swinging, and riding on wheels [18]. Open grassy areas or hard-surfaced spaces are suitable for ball games like soccer and badminton, which help enhance children’s cardiopulmonary endurance and lower-limb strength while fostering a sense of rules and teamwork [19]. Well-designed climbing frames, slides, and rope nets offer children opportunities to climb, hang, and slide, effectively building upper-body strength, balance, neuromuscular coordination, and movement response efficiency. Swinging helps exercise the vestibular function of the cerebellum and spatial perception. Flat and safe paths or designated areas support children in riding balance bikes, scooters, and bicycles, which are crucial for improving balance, overall coordination, and lower-limb strength [20]. Therefore, conducting scientific and systematic safety assessments of outdoor public activity spaces is an essential and indispensable component in building environments where children can enjoy physical activities without barriers and reap comprehensive health benefits.

However, current urban spatial planning often neglects the special needs of children, resulting in many safety hazards in outdoor public activity spaces, such as facility barriers [21], traffic hazards [22,23], crime dangers [24], and natural exposure risks [25]. These insecurities not only inhibit children’s willingness to participate in outdoor activities [26] but further contribute to increased sedentary behavior and health inequalities. In addition, unintentional childhood injuries are a major public health problem globally, especially in developing countries [27]. In China, 23.8% of deaths among children under 5 years of age originate from unintentional injuries [28], with falls and collisions during outdoor activities being the main causes of injury [29]. The lack of child-friendly spaces is closely related to the incidence of child injuries, and these data further highlight the urgency of building safe and inclusive outdoor spaces for children.

Although some studies have focused on children’s outdoor public activity spaces, existing research has limitations. Firstly, regarding research scope, most existing studies focus on individual space types or local area analysis, such as urban green spaces [30], communities [31,32], and playgrounds [33]. However, these studies lack a systematic assessment framework for evaluating the safety of children’s outdoor public activity spaces across urban contexts. Consequently, they fail to uncover common regularities or spatial heterogeneity among different areas, limiting the development of holistic safety optimization strategies for planning and decision-making. Secondly, regarding research perspectives, most existing studies prioritize hardware facilities, such as recreational equipment [34] and ground materials [35]. However, these studies neglect soft dimensions like differences in risk perception, children’s behavioral and psychological traits (e.g., interests), and sociocultural factors (e.g., parental guardianship habits). Consequently, spatial optimization schemes struggle to align with children’s actual needs and fail to adequately address the complexities of child safety across diverse sociocultural contexts.

Therefore, this study centers on the safety assessment and optimization strategies for children’s outdoor public activity spaces, targeting to transcend current research constraints and innovatively develop a comprehensive assessment framework encompassing multiple dimensions and spaces. This framework not only precisely evaluates the physical environmental safety of these spaces but also integrates children’s behavior patterns, psychological needs, and socio-cultural contexts into the assessment scope. Consequently, it can fully reflect the comprehensive impact of all factors on children’s safety. By leveraging multidisciplinary methodologies, this study offers crucial theoretical backing and practical guidance for developing CFC. It aims to create a safe, comfortable, and vibrant environment for children’s growth, ultimately advancing the creation of environmentally and socially sustainable urban settings.

2. Research Methods

2.1. Methodological Framework

This study comprised 5 stages. The first phase involved literature surveys and field surveys in selected areas to collect preliminary information on indicators for assessing the safety of children’s outdoor public activity spaces. Subsequently, we utilized NVivo 12 Plus to code the initial data that had been collected. This process involved three levels of coding: initial coding, focused coding, and axial coding. We also performed a theoretical saturation test and reliability and validity tests, ultimately forming the initial assessment indicators. Based on the results of the indicator coding, a questionnaire on the safety of children’s outdoor public activity spaces was developed and distributed to the target population (parents of children), thereby establishing a robust data foundation for subsequent analyses. Then, we used SPSS 23.0 to conduct principal component analysis (PCA) on the results of the questionnaire distribution. We performed a suitability test to confirm data appropriateness for PCA, extracted and screened factors, and validated the dimensional structure through correlation analysis, determining the indicators. Finally, based on the factor rotation component matrix output from the PCA, we further determined the weights of each indicator to form a comprehensive assessment indicator system for the safety of children’s outdoor public activity spaces. The detailed process is shown in Figure 1.

2.2. Study Area

The study area is located in Shanghai, a core city within China’s Yangtze River Delta urban cluster and a pivotal hub for national economic, financial, trade, and shipping activities. Shanghai has a northern subtropical monsoon climate, which features four distinct seasons and a mild, humid climate, making it suitable for all kinds of outdoor PA. The total area of Shanghai is 6340.5 square kilometers, with a permanent population of 24,802,600 by the end of 2024 [36]. The rich urban demographic structure and highly developed economic and cultural environment provide a broad demand and diverse practice scenarios for the construction and development of children’s outdoor public activity spaces.

Based on the administrative divisions of Shanghai’s central and peripheral urban districts, this study employs stratified sampling methods to select 13 representative children’s outdoor public activity spaces for field surveys, including observations, interviews, and questionnaires. The selected spaces cover multiple administrative districts, including Pudong, Hongkou, Changning, and Minhang, and encompass a diverse range of spatial forms and functions. These include children’s playgrounds, sports parks, urban green spaces, commercial sunken plazas, rooftop spaces, under-bridge spaces, and community open spaces. The specific park names and their distribution are shown in Figure 2. This sampling method ensures that the sample reflects the overall characteristics of children’s outdoor public activity spaces in Shanghai, considering both geographical balance and functional diversity.

2.3. Data Collection

This study began with a comprehensive literature review using academic databases to identify 125 core documents strongly related to the research theme. Additionally, 13 national standards, guidelines, and norms were referenced. Based on these materials, a detailed field survey plan was developed, covering the time, location, subjects, and methods of the survey. The initial field surveys were conducted in two stages. Firstly, direct observations were carried out in the selected areas, focusing on children’s behavior, the use of space facilities, and potential safety hazards. Subsequently, semi-structured interviews were conducted with parents of children, space managers, and staff to gather their evaluations and suggestions on the safety of children’s outdoor public activity spaces. The preliminary research outcomes include the 125 core articles, 13 national standards, guidelines, and norms, as well as field survey data comprising semi-structured interview records, observational logs, and photographs of space usage. Figure 3 presents typical photos of space usage. These photos document key facility types, usage status, and potential risk points in the surveyed space. Specific elements include children’s climbing areas, slides, sand activity areas, ground paving conditions, playground equipment, step designs, and plant diversity. These visual materials, combined with textual data, provide strong support for subsequent indicator coding.

Based on the results of the indicator coding, this study developed a questionnaire covering the safety of children’s outdoor public activity spaces. The questionnaire contained two parts. The first part was the respondents’ basic personal information, including demographic variables, such as gender, age, and educational level. The second part was an assessment of indicators of children’s outdoor public activity spaces safety using a 5-point Likert scale. The results of the previous field survey showed that children were mostly accompanied and cared for by their parents in outdoor public activity spaces. Parents, as the primary guardians and educators of children, play a uniquely important and irreplaceable role in shaping their development. Consequently, parents of children aged 12 years old and younger were used as the respondents of the questionnaire in this study. The questionnaire was designed to assess the factors influencing parents’ perceptions of the safety of children’s outdoor public activity spaces.

2.4. Respondents’ Socioeconomic Characteristics

Of the 561 questionnaires distributed, 509 valid responses were collected (response rate: 90.7%). The data in

Table 1. Summary of the socioeconomic demographic profile of respondents.

General Information of Respondents Profile	Categories	Frequency	Percentages (%)
Child’s gender	boy	259	50.9
	girl	250	49.1
Child’s age	Infancy and early childhood (under 3 years old)	68	13.4
	Preschool age (3–6 years old)	148	29.1
	School age (7–12 years old)	293	57.5
Parent’s gender	Male	207	40.7
	Female	302	59.3
Parent’s age	20–29 years old	42	8.3
	30–39 years old	393	77.2
	40–49 years old	69	13.5
	50 years old and above	5	1.0
Education level	Junior high school and below	8	1.6
	High school/vocational high school	39	7.7
	College	90	17.7
	Bachelor’s degree	295	57.9
	Master’s degree	66	12.9
	Doctoral degree and postdoctoral degree	11	2.2
Monthly household income (yuan/month)	6000 and below	60	11.8
	6001–9000	98	19.3
	9001–12,000	99	19.4
	12,001–17,000	75	14.7
	17,001–25,000	53	10.4
	25,001–35,000	68	13.4
	Over 35,000	56	11.0

provide a thorough description of the socioeconomic profile of the survey respondents, covering the child’s gender and age, the parent’s gender and age, education level, and monthly household income. These factors are critical for assessing how elements in outdoor public activity spaces affect the safety of children’s activities.

This comprehensive demographic profile illustrates the diverse socio-economic backgrounds of the survey respondents. The gender distribution of the children surveyed is nearly equal, with girls accounting for 49.1% and boys accounting for 50.9%. The age distribution shows that the majority of children belong to the 7–12 years age group (57.5%), followed by the 3–6 years age group (29.1%) and the 0–3 years age group (13.4%). This reflects the tendency of older children to participate in outdoor activities more frequently, for longer durations, and across a wider variety of facilities.

The respondents were primarily parents, with females comprising 59.3%. This demographic distribution reflects the tendency for mothers to be more actively involved in the care and supervision of their children’s outdoor activities compared to fathers [37]. The age distribution of the respondents shows that the majority belong to the 30–39 years age group (77.2%), which aligns with the age structure of the children surveyed. In terms of monthly household income, the distribution across different income groups was relatively balanced. Families with a monthly income between 6001 and 12,000 yuan accounted for the highest proportion (38.7%), while those with a monthly income of 12,001 yuan or above accounted for 38.5%. This indicates that a significant portion of respondents belong to middle- and high-income groups, suggesting relatively favorable economic conditions compared to the national average.

2.5. Data Analysis

2.5.1. Qualitative Analysis

NVivo 12 Plus is a computer-assisted qualitative data analysis software used in qualitative research [38]. It can handle data in various formats, including text, audio, video, images, and social media content. This capability enables researchers to uncover patterns and associations in the data through systematic coding and analysis [39]. This study employed NVivo 12 Plus as the research tool to code indicators from 125 core documents, 13 references to national standards, guidelines, and norms, as well as field interview and observation records.

In the initial coding stage, free nodes were created by browsing the source material word by word, refining the key information, and coding the content to the corresponding nodes. Then, through viewpoint comparison, the nodes were modified to obtain 171 non-repetitive expressions. In the focused coding stage, the initial coding names were diffused into conceptual categories, and similar categories were merged. Through repeated comparison and screening, the intrinsic relationships of each initial coding node were connected, the hierarchy was improved, and the connections between various concepts and categories were established. Finally, 32 nodes were defined, and rough indicator descriptions were obtained (see

Table A1. Interpretation of indicators for assessing the safety of children’s outdoor public activity spaces.

Indicators	Interpretation of Indicators
Ground-level difference treatment	Elimination of high platforms or the treatment of platforms with different height differences, with platform height appropriate to ensure crossing comfort. Step width, number of steps, length, and height in line with the requirements of the corresponding age group and coordinated with the width of the preceding and following facilities. The form and slope control of site ramps to ensure smooth passage, taking into account drainage and skid prevention on the ramps.
Ground fall cushioning design	Fall protection areas on the ground, constructed with protective materials. Different surfacing materials and thicknesses correspond to different fall height ranges.
Ground pavement characteristics	The paving materials should be non-toxic, durable, slip-resistant, well-draining, and elastic. The thickness and protective function of loose-fill materials should be maintained.
Safety railings, protective netting, and handrails	Appropriate spacing railings are added to equipment with large heights. The height of safety railings and the spacing between vertical bars of railings are strictly set in accordance with specifications. Handrails are added to slopes, platforms, and ladders. Railings are installed to protect open water. Railings or nets are set up in hazardous areas and boundary areas to prevent stepping over. Handrails and handles are firm and suitable for gripping.
Safety warnings, use requirements, and other signs	Warning signs for hazardous areas such as slopes, sandy areas, and water bodies. Instructions for the use of facilities, with easily recognizable signs.
Specifications of facility components	The size of the components, the inner diameter of the openings, the gaps, and the distances are designed to be ergonomically appropriate to prevent pinching. The angles, heights, and gaps in the spatial network of the components ensure safety.
Basic parameters of the facility	The facility features adequate drop height, swing area, and buffer space. The slide facility has an optimal angle, smooth speed, and appropriate length, and the facility’s structure is stable with an appropriate load capacity.
Facilities maintenance	The facility management ensures the replacement and renewal of aging facility components, conducts regular inspection, maintenance, and disinfection of the facility, and provides maintenance for materials exposed to excessive sun, wind, and rain.
Age appropriateness of facilities	Facility designs are simple or follow a regular pattern, offering challenges and fun to meet children’s needs. Different facilities are provided for toddlers, preschoolers, and school-age children. Facilities are restricted for adult use.
Hidden design and polishing treatment	Corners are sanded or rounded to avoid sharp edges. Screws are designed to be hidden from touch.
Water and sand setup	Water quality is ensured through filtration or regular water replacement. The pool depth is appropriate, and the size of the fountain holes and the jet pressure are properly adjusted. The perimeter should be treated for non-slip, ensuring water quality hygiene and complete protective measures. Reliable stepping platforms and stepping stones should be set up for wading in the water. Safety protection against falls should be provided for open water areas. Sand pool containers should be fixed rather than inflatable. The volume of sand filling material should be appropriate to avoid sand and dust in the eyes. Sand should be selected to be finer and softer, with hardened clumps regularly cleaned and replaced, and debris removed.
Material environmental friendliness and composition	Control of heavy metals in soil and raw materials for facilities and equipment, use of environmentally friendly materials that are non-toxic and have no pungent odor, and avoidance of hazardous chemicals and toxic elements in materials.
Material softness and texture	Choose materials with strong softness and good elasticity, and use soft and lightweight materials, such as plastic and wood, to avoid exposed metal materials.
Corrosion resistance, anti-slip, and fire resistance of materials	Instrument metal components are treated for anti-rust and anti-breakage. Wood materials are treated to prevent rotting and loosening. Non-perishable and pest-resistant wood is used, with protective paint treatment. Slipping and falling are avoided during climbing, contact, and water activities. Flammable materials should not be used to avoid the risk of fire and related hazards.
Stability and toughness of materials	Use sturdy materials and materials that are tough and not easily broken when deformed, such as wood and plastic. Avoid brittle and fragile materials, such as ceramic tile and glass.
Spatial arrangement	The spatial layout is clearly planned, with functional zoning for activities, caretaking, isolation, etc. Static and dynamic activity spaces are divided, and the zones are well-connected. The layout of the facilities is rational, with controlled site area and structure.
Site selection	Avoid selecting areas with potential sources of danger. The site is primarily for residential, commercial, and educational purposes with convenient transportation. Implement air pollution prevention measures. Control the site’s noise level within a reasonable decibel range to avoid noise pollution. Ensure high ventilation for physical structures susceptible to high temperatures. Set up facilities upwind in areas with strong natural winds.
Spatial openness	Set up a suitable number of entrances and exits with clear paths. Create an appropriate sense of enclosure in the space while ensuring permeability and enhancing natural surveillance. Avoid external instability factors and restrict the entry of idle and unrelated individuals, such as salespersons.
Space-carrying capacity	Ensure an appropriate service radius and capacity with size control. Promote the dispersion of pedestrian traffic in the area.
Site animals	Beware of insect bites and allergies. Be aware of stray dogs, cats, and birds on the grounds. Pets are restricted from entering children’s activity areas.
Pedestrian–vehicle separation	Divided from traffic flow boundaries and other types of activity areas. Set up convenient and safe crossings to facilitate crowd movement.
Road access and speed limits	Restrict access to children’s vehicles and other items that pose a traffic collision hazard. Implement roadway markings, reduce travel speeds for passing vehicles, or enforce speed limits.
Plant varieties	Avoid planting poisonous, thorny, catkin-bearing, allergy-inducing, and disease-susceptible plants.
Plant morphology	Plant branching should ensure spatial permeability. Planting density and height should be reasonably controlled. The clear space under tree branches should meet safety sight distances and facilitate pedestrian flow.
Barrier-free facilities setup	The ground provides barrier-free access for wheelchair and stroller users.
Supporting facilities setup	Provide facilities for sanitation, water supply, caretaking, and resting. These facilities meet the demand for use and are located at an appropriate distance from the activity area.
Lighting facilities setup	Ensure light intensity and avoid glare. Ensure the type, density, and number of light sources for nighttime lighting are appropriate. Ensure nighttime lighting covers the activity areas.
Sanitation Facilities configuration	The facility is equipped with sanitary facilities for disease prevention, temperature measurement, and disinfection.
Guidance on the use of facilities	Provide guidance and correction for the use of children’s facilities. Prevent foot injuries and reverse sliding hazards on slides.
Emergency protection facilities and systems	Emergency response and contingency plans. Emergency medical assistance and material supplies. Knowledge of firefighting equipment and emergency evacuation plans. Purchasing insurance. Electrical safety measures. Prevention and preparedness for severe weather conditions.
Safety accountability system	Identify the responsibilities and duties of relevant departments in the ground’s maintenance regulations. Equip with personnel for supervising children’s activities, security, patrols, cleaning, maintenance, and management. Equip with street eyes and electronic surveillance equipment.
Safety feedback	Ensure the availability of communication and help-seeking devices for children. Provide easy and fast channels for feedback and communication in the space.

). In the axial coding stage, the attributes and dimensions of each indicator were specified by analyzing the similar conditions, contexts, and action strategies of the phenomenon. Therefore, core thematic terms were refined to focus on key points.

After building the infrastructure through three levels of coding, a theoretical saturation test was conducted. The test results showed that the conceptualized meaning units and referent categories in the extracted node framework were further developed, and no new categories and relationships have been formed since then. The keywords and concepts obtained from the test data were covered by the existing indicator nodes, indicating that the coding had reached saturation [40].

The reliability of the study was ensured through the use of interview outline-assisted control and retest reliability. Additionally, peer review and expert evaluation were employed to ensure the representativeness and completeness of the node codes and derived indicators, thereby ensuring the validity of the study. Based on the experts’ feedback, the indicator framework was adjusted and improved, and the final structure met the criteria for reliability and validity.

2.5.2. PCA

PCA is a widely used data processing technique proposed by statistician Pearson. Its core is to reduce the dimensionality of the dataset while retaining most of the information of the original data. In turn, a few principal components that can represent the main features of the original data are extracted [41]. In this study, PCA was selected to analyze the results of the questionnaire for indicator screening and weight determination.

The data collected from the questionnaires were entered into SPSS 23.0 for the Kaiser–Meyer–Olkin (KMO) and Bartlett’s test of sphericity. The KMO value should exceed 0.5, and the p-value of Bartlett’s test of sphericity should be less than 0.05 to ensure that the data are suitable for PCA [42].

Firstly, based on the Kaiser rule, the factors with original eigenvalues greater than 1 were extracted, and the varimax orthogonal rotation was applied to obtain the rotated component matrix. According to the rotation results, indicator variables with factor loadings greater than 0.5 were categorized into the corresponding factors to form a preliminary dimension division. During the dimension construction process, the extracted factors were conceptualized and named using professional knowledge to ensure their theoretical significance was clear and interpretable.

To verify the rationality of the internal structure of the dimensions, Pearson correlation coefficients among indicators within each dimension were further calculated. When the absolute value of the correlation coefficient between indicators exceeded 0.7, expert review and content validity analysis were used to screen out indicators with semantic overlap or highly similar measurement content. This helped eliminate information redundancy and ensured the independence and effectiveness of the indicator system.

Based on the rotated component matrix output from the PCA, the weights of the dimensional factors were calculated. The principal component weights were calculated as follows:

$$A_i=C_i/{\sum }_{i=1}^n{C}_i$$

(1)

where $A_i$ represented the weight of the $i$-th principal component, $C_i$ represented the variance contribution rate of the $i$-th principal component, and n represented the number of extracted common factors.

The weight value of each single indicator on the common factor dimension was calculated by normalizing the factor score coefficients. The formula for calculating the weights of single indicators was

$$A_{ij}=a_{ij}/{\sum }_{j=1}^m\left|a_{ij}\right|(i=1, 2\dots n)$$

(2)

where $A_{ij}$ represented the weight of the $j$-th indicator on the $i$-th common factor, $a_{ij}$ represented the factor score coefficient of the $j$-th indicator included in the i-th common factor, and $m$ represented the number of indicators included in the $i$-th common factor.

Finally, the weight of each single indicator on the overall safety was calculated. The formula for calculating the combined weights was

$${\omega }_j=A_i\times A_{ij}$$

(3)

where ${\omega }_j$ represented the weight of each single indicator on overall safety.

3. Results

3.1. Main Factors

The study quantitatively assessed the factors influencing the safety of children’s outdoor public activity spaces using PCA. Data from 509 valid questionnaires were entered into SPSS 23.0. The KMO value was 0.947, and the p-value of Bartlett’s test of sphericity was 0.000, indicating that the data were suitable for factor analysis.

During the analysis, we extracted a total of seven factors with original eigenvalues greater than 1, with a cumulative variance contribution rate of 71.066% after rotation (

Table 2. Eigenvalues and variance contribution rate.

Principal Components	Eigenvalue	Variance Contribution Rate (%)	Cumulative Variance Contribution Rate (%)
1	5.462	17.069	17.069
2	3.670	11.470	28.539
3	3.074	9.606	38.145
4	2.954	9.232	47.377
5	2.913	9.102	56.479
6	2.334	7.294	63.774
7	2.334	7.292	71.066

).

According to the rotated component matrix, we grouped the indicator variables with factor loadings greater than 0.5 into one group for each common factor, resulting in seven principal components (Figure 4). The output results of the seven principal components indicate that each principal component contains at least one factor loading greater than 0.5, demonstrating the effectiveness of the extracted principal components. Based on the framework and content of the indicator design, the seven principal components were named as follows: site facilities, spatial conditions, site management, material conditions, service facilities, ground conditions, and traffic and landscape. In each principal component, indicators with factor loadings greater than 0.5 are classified into one category, indicating that these indicators have higher representativeness in the corresponding principal component. For example, in site facilities, indicators such as basic parameters of the facility and facilities maintenance have higher factor loadings, which suggests that these indicators are key factors in assessing the safety of site facilities. Meanwhile, some indicators have certain factor loadings in multiple principal components, but the magnitudes of these factor loadings vary. For instance, the factor loading of site animals in spatial conditions is significantly higher than that in site facilities, indicating that it is more important in terms of spatial conditions. The factor loadings of the 32 indicators on their respective principal components all exceed 0.5 (ranging from 0.517 to 0.803), which indicates that the indicators within the same dimension can effectively measure the same underlying safety construct, demonstrating good convergent validity. Meanwhile, the vast majority of indicators have significantly higher factor loadings on their target dimensions compared to other dimensions, with only a few indicators having loadings close to those of other dimensions. The overall discriminant validity is satisfactory. These results provide strong support for the scientific nature and effectiveness of the assessment system.

To reduce the redundancy of information among indicators within the same dimension, we conducted a correlation analysis of the initial indicators across seven dimensions. By calculating the correlation coefficients for each pair of indicators, we found that the correlation between most indicators was below the threshold of 0.7. However, the correlation coefficient between the two indicators, “pedestrian–vehicle separation” and “road access and speed limits”, in the “traffic and landscape” dimension was 0.717 (

Table 3. Correlation coefficients of indicators under traffic and landscape dimension.

Indicators	Pedestrian–Vehicle Separation	Road Access and Speed Limits	Plant Varieties	Plant Morphology
Pedestrian–vehicle separation	1	0.717	0.468	0.472
Road access and speed limits	0.717	1	0.426	0.424
Plant varieties	0.468	0.426	1	0.592
Plant morphology	0.472	0.424	0.592	1

), indicating a relatively strong correlation; hence we decided to retain both indicators. This decision was based on the conceptualization of the indicators, as they focus on different aspects of facility construction and management, both of which are closely related to the transportation environment.

3.2. Indicator Weights

Based on 509 valid questionnaires, this study constructed an indicator system for assessing the safety of children’s outdoor public activity places using PCA. The system includes 32 specific indicators in seven dimensions. The weights of these indicators have been standardized, and the higher the weight value, the greater the importance of the indicator in the safety assessment of children’s outdoor public activities (Figure 5). The distribution of weights for these indicators offers us a deep understanding of the factors affecting the safety of children’s public outdoor activity spaces and helps us identify and prioritize key areas for safety improvement.

The findings of this study revealed significant variations in the influence of different dimensions on safety. Specifically, the dimension of site facilities had the highest weight at 24.0%, indicating its pivotal role in ensuring safety. This was followed by spatial conditions (16.1%), site management (13.5%), material conditions (13.0%), and service facilities (12.8%), further emphasizing the importance of physical environment design in safety assurance. In contrast, the dimensions of ground conditions and traffic and landscape had the lowest weights, both at 10.3%.

At the level of specific indicators, the weight distribution among each indicator was relatively balanced. However, some indicators had prominent weights and significantly impacted safety. These included ground pavement characteristics (3.57%), ground fall cushioning design (3.55%), guidance on the use of facilities (3.45%), and corrosion resistance, anti-slip, and fire resistance of materials (3.39%), which should be prioritized for optimization. The higher weights of safety feedback (3.37%), emergency protection facilities and systems (3.36%), and safety accountability system (3.34%) within the site management dimension underscored the importance of dynamic safety management in children’s activity spaces. In contrast, the four indicators in the traffic and landscape dimension had relatively lower weights, indicating their secondary impact on the safety of children’s outdoor public activity spaces.

4. Discussion

This study employs PCA to construct an assessment indicator system for the safety of children’s outdoor public activity spaces. The system comprises seven dimensions: ground conditions, site facilities, material conditions, spatial conditions, traffic and landscape, service facilities, and site management. It includes a total of 32 specific indicators, which provide a quantitative foundation for enhancing the safety of outdoor public activity spaces.

4.1. Site Facilities

The site facilities dimension consists of eight specific indicators. These indicators are ranked below in descending order of weight: B8—Water and sand setup (3.18%) > B3—Specifications of facility components (3.12%) > B4—Basic parameters of the facility (3.08%) > B6—Age appropriateness of facilities (2.96%) > B1—Safety railings, protective netting, and handrails (2.95%) > B2—Safety warnings, usage requirements, and other signage (2.94%) > B5—Facilities maintenance (2.91%) > B7—Hidden design and polishing treatment (2.87%).

The water elements (such as landscape fountains, ponds, and wading paths) and sand elements (such as activity sandpits and sandy paving) in the space are highly attractive to children, prolonging their activity time and attention [43]. The fluid nature of water and sand provides a foundation for children’s imagination and creativity [44] and promotes social collaboration and practical skills through group play. The specifications and basic parameters of facility components directly affect children’s PA. The spatial distribution of components, drop height, swing amplitude, and buffer space of sliding facilities intuitively influence the children’s psychological perception of safety.

The age appropriateness of facilities depends on the site. Child-dedicated facility areas focus on age-appropriate zoning design, while parent–child spaces transform parents’ roles from passive supervisors to co-participants through compatible program combinations. This increases the amount of high-quality time parents spend with their children, thereby effectively enhancing family cohesion [45].

Safety rails, protective netting, and handrails, as well as safety warnings, usage requirements, and other signage, are indispensable and crucial aids. They are effective physical facilities that have been explored through practical experience. Facilities maintenance ensures that play equipment and other outdoor facilities are in good condition to prevent accidental injuries due to aging or damaged equipment. Hidden design and polishing treatments are based on references to children’s movement paths and physical development.

4.2. Spatial Conditions

The spatial conditions dimension consists of five specific indicators. These indicators are ranked below in descending order of weight: D4—Space-carrying capacity (3.35%) > D1—Spatial arrangement (3.33%) > D2—Site selection (3.28%) > D3—Spatial openness (3.18%) > D5—Site animals (3.03%). Tang et al. also reported that spatial arrangement, site selection, and spatial openness have significant impacts on urban children’s outdoor activity spaces [37].

The choice of outdoor activity environments for children prioritizes proximity to residential areas and appropriate space occupancy rates, based on the accessibility of the site and facilities. Spaces adjacent to residential areas significantly reduce parents’ supervisory stress by lowering family time costs and alleviating safety concerns [46]. The layout design, including the division of static and dynamic areas and the allocation of supervision zones, directly affects the shared experience of parents and children.

Considering the public nature of the space, it is important to ensure a moderate level of enclosure and natural surveillance during children’s social interactions. This helps maintain a safe environment. Safety personnel are responsible for restricting the entry of idle individuals and salespeople. Additionally, pet restrictions and the safety management of stray animals are also key considerations in some spaces.

4.3. Site Management

The site management dimension consists of four specific indicators. These indicators are ranked below in descending order of weight: G1—Guidance on the use of facilities (3.45%) > G4—Safety feedback (3.37%) > G2—Emergency protection facilities and systems (3.36%) > G3—Safety accountability system (3.34%).

Children enjoy climbing steep slopes and rock climbing in parks. This type of risk-taking exploration can cultivate children’s frustration tolerance [47]. The psychological resilience gained through such outdoor activities can be transferred to the academic realm, endowing children with greater perseverance and flexible problem-solving skills when facing academic challenges in the future. However, without proper guidance and supervision, these activities can easily lead to injuries such as falls, sprains, cuts, and trampling. Therefore, facility usage guidance (such as safety route markings and skill demonstrations) and joint supervision by space managers and parents are essential.

Safety feedback serves as an important bridge for encouraging children’s self-expression and improving the educational environment through two-way interaction. The accessibility and smoothness of communication and emergency call channels for children provide the prerequisite conditions. Emergency protection facilities and systems are designed to address potential adverse factors and contingencies that may arise during outdoor activities. By establishing organized and planned emergency response plans and equipping them with essential infrastructure, these facilities and systems are capable of preventing issues before they occur.

From the management personnel’s perspective, the safety accountability system outlines the logistical support and regulatory responsibilities for children’s activities. This system is supported by specialized staff responsible for supervision, safety, patrolling, cleaning, and maintenance. Additionally, it includes the installation of street surveillance and electronic monitoring equipment. These measures can provide children with a safe environment for activities, thereby promoting their autonomous exploration behaviors [48].

4.4. Material Conditions

The material conditions dimension consists of four specific indicators. These indicators are ranked below in descending order of weight: C3—Corrosion resistance, anti-slip, and fire resistance of materials (3.39%) > C4—Stability and toughness of materials (3.24%) = C2—Material softness and texture (3.24%) > C1—Material environmental friendliness and composition (3.12%).

The materials and components of facilities that come into direct contact with children’s bodies can pose potential safety risks. Exposed rusty surfaces, loose screws, and waterlogged, soft wooden structures all pose hazards to children’s activities. In the summer, metal materials can quickly heat up under solar radiation. Therefore, their surfaces need to be treated with insulating materials to enhance comfort upon contact. In parent–child interactive spaces, the load-bearing capacity and stability of facilities should be considered. The materials selected for the underlay of climbing structures should emphasize elasticity, lightness, and softness. For health reasons, soil heavy metal content and the chemical composition of materials are also important factors to consider.

4.5. Service Facilities

The service facilities dimension consists of four specific indicators. These indicators are ranked below in descending order of weight: F3—Lighting facilities setup (3.3%) > F1—Barrier-free facilities setup (3.21%) > F4—Sanitation facilities configuration (3.17%) > F2—Supporting facilities setup (3.13%).

Given that dark environments and the fear of the unknown have a more pronounced impact on children’s psychology and behavior, the frequency of children’s activities at night is significantly lower than during the day. Therefore, lighting facilities are particularly essential in nighttime settings [49]. For strollers and infant pushchairs, convenient barrier-free passages eliminate travel difficulties. Studies have also highlighted the importance of these barrier-free passages in ensuring the outdoor activities of children with disabilities [50]. Sanitation facilities, including waste disposal, drinking water, restrooms, supervision, and rest areas, are relatively well-configured in outdoor public activity spaces. Consequently, these features are perceived as relatively less important by users.

4.6. Ground Conditions

The ground conditions dimension consists of three specific indicators. These indicators are ranked below in descending order of weight: A3—Ground pavement characteristics (3.57%) > A2—Ground fall cushioning design (3.55%) > A1—Ground level difference treatment (3.14%).

Under the ecological concept of sponge cities, the selection of ground paving materials is focused on slip resistance and drainage while also maintaining the thickness and protective function of loose fill surfaces [51]. In the construction of fall protection zones for activity facilities, suitable materials and corresponding surface thicknesses should be chosen based on the height of the facility. The reasonable design of step width, the number of steps, length, and height, along with effective control of ramp form and gradient, ensures that these elements are in line with the physiological scale of children. This, in turn, meets the requirements for walking and jumping and ensures the stability of their activities.

4.7. Traffic and Landscape

The traffic and landscape dimension consists of four specific indicators. These indicators are ranked below in descending order of weight: E1—Pedestrian–vehicle separation (2.62%) > E2—Road access and speed limits (2.56%) > E3—Plant varieties (2.55%) > E4—Plant morphology (2.53%).

Children’s outdoor spaces, particularly those located near major traffic routes and intersections, in sidewalk areas, and under elevated structures, require special attention to the impact of traffic flow on accessibility and activity. In riverside greenways and cycling areas, it is particularly important to separate functional zones and designate specific activity areas [52]. Traffic and recreational activities are the main forms of PA in outdoor spaces [53]. Therefore, managing collision hazards and enforcing speed limits is crucial for regulating activity behavior and maintaining order.

With the growing prominence of “nature-deficit disorder”, there is an increasing urgency for children to engage with natural environments. Natural landscapes play a significant role in spatial design, serving not only as a key resource for cultivating children’s aesthetic tastes and providing natural education but also significantly enhancing their sense of safety and belonging to the environment [54]. Engaging with nature through activities like plant identification not only enhances children’s observational skills and academic performance but also lays the foundation for future creativity and inquiry abilities [55]. Therefore, it is recommended to increase plant diversity and enrich the variety of plants in children’s outdoor public activity spaces to better meet their needs. When selecting plant varieties, it is necessary to consider the characteristics of plants to avoid those that are toxic, thorny, fluff-producing, or prone to disease, as these can cause injuries and allergic reactions in children. Attention should also be paid to plant morphology, including branch bifurcation and leaf growth. Planting density and growth height should be reasonably controlled to ensure clear space under trees and maintain the transparency of the space [56].

4.8. Limitations of the Study

Although this study has identified key factors affecting the safety of children’s outdoor public activity spaces, the generalizability of the findings is subject to certain limitations.

First, the data for this study were collected exclusively from Shanghai, an international metropolis. Shanghai’s unique socioeconomic structure, cultural background, and policy environment may differ significantly from those of other cities, especially in smaller or economically less developed areas. As such, the external validity of the results may be limited. Future research should be conducted in a wider range of cities and regions to enhance the generalizability of the conclusions. Second, the respondents in this study were limited to parents of children under 12 years old. Since parents of younger children may lack a comprehensive understanding of the safety needs of adolescents, the findings may not fully reflect the safety needs of children in the adolescent stage. Future studies should include a broader range of respondents, such as adolescents themselves and their parents, to strengthen the generalizability of the findings. Third, this study primarily relied on parental subjective perceptions, lacking objective safety or injury data. Parental feedback may be influenced by factors such as personal experience, education level, and socioeconomic status, which can affect the accuracy and objectivity of the data. Future research could incorporate objective data, such as child injury rates and quantitative assessments of safety facilities, to enhance the reliability of the findings. Additionally, this study employed a cross-sectional design, collecting data at a single point in time. This approach does not capture dynamic changes over time. Future research should consider longitudinal studies to track the evolution of child safety issues and obtain more comprehensive data.

Given these limitations, future research should integrate multiple methods and sources of samples to gain a more holistic understanding of children’s outdoor safety issues. Policymakers and relevant organizations should also take into account the limitations and applicability of the study when developing child safety strategies and tailor interventions to local contexts.

5. Conclusions

This study constructs a comprehensive safety assessment indicator system for children’s outdoor public activity spaces, taking Shanghai as a case. The study identified 32 specific indicators under seven dimensions by observing the behavioral characteristics of children’s outdoor PA, investigating their safety perceptions, and analyzing potential safety risks. The significance of this study lies in its methodological and practical contributions. From a methodological perspective, this study provides a comprehensive and scientific approach to assessing the safety of children’s outdoor public activity spaces. It provides a robust scientific foundation for the development of regional safety standards and standardized management practices. Additionally, it contributes to the refinement of localized theoretical frameworks and offers novel perspectives for research on children’s PA safety in open spaces. At the practical level, the safety assessment indicator system for children’s outdoor public activity spaces constructed in this study provides a scientific tool for identifying and preventing safety hazards in outdoor public activity spaces and provides strong scientific support for improving the design and safety management of children’s outdoor activity spaces. At the same time, these indicators can be transformed into intuitive safety guidelines to provide caregivers with risk warnings and guardianship references, thus helping them to protect children’s safety more effectively.

In conclusion, this study provides valuable insights into the safety of children’s outdoor public activity spaces. A holistic, data-driven planning approach can help cities create safer, friendlier, and more sustainable spaces for children’s activities, ultimately promoting children’s healthy growth.