Assessing the Impact of Urban Green Spaces on Air Quality in Metropolitan Areas

Thesis Abstract

Urban air pollution remains a pressing challenge in densely populated metropolitan regions, where rapid urbanization and industrial activities have significantly degraded air quality, posing serious public health risks and environmental concerns. This study aims to empirically assess the extent to which urban green spaces influence air quality parameters—specifically PM2.5, PM10, NO2, and O3—in the metropolitan area of Metro City. The specific objectives include quantifying variations in air pollutant levels in areas with differing degrees of green space coverage, examining residents' perceptions of air quality improvements associated with green spaces, and identifying other socio-environmental factors that modulate these relationships. The overarching purpose is to provide a comprehensive understanding of green spaces’ role in urban air quality management, informing city planning and environmental policies. The research adopts a mixed-methods design, integrating both quantitative and qualitative approaches to capture the multifaceted impact of green spaces on air quality. Quantitatively, a cross-sectional survey will be conducted, targeting a population of approximately 1,200 residents classified across neighborhoods with high, moderate, and low green space coverage, selected through stratified random sampling. Air quality data will be collected over a twelve-month period using portable air quality sensors deployed at 15 strategically chosen locations—five in each green space coverage category—validated against certified stationary monitoring stations. The sensors will continuously record data on PM2.5, PM10, NO2, and O3, which will be subsequently analyzed. Qualitative data will be obtained through focus group discussions and semi-structured interviews with local residents and urban planners, exploring perceptions and policy perspectives on green space benefits. Data analysis involves the application of multiple statistical techniques. Descriptive statistics will summarize pollution levels and demographic variables. Inferential analyses, including one-way ANOVA tests, will compare pollutant concentrations across different green space zones. Regression analysis will be employed to model the relationship between green space extent and air quality indices, controlling for confounding factors such as traffic density and industrial activity. Thematic analysis will interpret qualitative insights, providing contextual understanding of community perceptions and policy implications. The study is grounded in the Biophilia Hypothesis and Urban Ecosystem Service Theory, providing a theoretical foundation for understanding how green spaces influence human health and environmental quality through ecological and psychological mechanisms. Expected findings suggest that neighborhoods with higher green space coverage will exhibit significantly lower concentrations of airborne pollutants, an outcome supported by existing literature, but with nuanced insights into the levels of pollution reduction achievable in different urban contexts. The study anticipates revealing that residents perceive noticeable improvements in air quality in greener areas, although awareness of green space benefits varies based on sociodemographic factors. Additionally, the analysis may identify moderating variables such as green space quality and accessibility. This research contributes novel empirical evidence to urban environmental management literature by quantitatively linking green space metrics with real-time air quality data, filling existing gaps concerning localized impacts within Metropolitan areas. It advances theoretical understanding by integrating ecological models with human health perspectives, providing a multidisciplinary framework for urban sustainability. In conclusion, the findings are expected to reinforce the importance of strategic urban greening initiatives as sustainable approaches to mitigate air pollution. Recommendations will include policy measures promoting the integration of green infrastructure in urban planning, enhancing green space accessibility, and raising public awareness about ecological health benefits. The study also suggests avenues for future research, including longitudinal analyses to evaluate long-term impacts and the role of specific plant species in pollution absorption. Overall, this thesis aims to serve as an evidence-based guide for policymakers, urban planners, and environmental advocates committed to fostering healthier, sustainable metropolitan environments.