Impact of Air Pollution on Urban Respiratory Health Outcomes: A Systematic Review From Pakistan’s Perspective

Abstract

Background: Air pollution is a major public health concern in rapidly urbanizing cities, contributing to respiratory morbidity and mortality. Urban populations in Pakistan are increasingly exposed to high levels of particulate matter and gaseous pollutants, yet comprehensive evidence on associated respiratory health outcomes remains fragmented. Objective: To systematically review existing literature on the effects of air pollution on respiratory health among urban populations in Rawalpindi, Pakistan. Methods: A systematic review was conducted over three months, including 35 studies encompassing 78,245 participants. Studies reporting quantitative respiratory outcomes such as asthma prevalence, chronic bronchitis, lung function measurements (FEV1, FVC), and hospital admissions related to air pollution exposure were included. Data on ambient PM2.5, PM10, NO2, and SO2 concentrations were extracted. Descriptive statistics summarized participant demographics and pollutant levels, while parametric tests, including Pearson correlation and independent t-tests, assessed associations between pollutant exposure and respiratory outcomes. Results: Average annual PM2.5 and PM10 concentrations exceeded WHO guidelines, reaching 120 µg/m³ and 220 µg/m³, respectively. Asthma prevalence was 9.8%, chronic bronchitis 6.4%, and hospital admissions averaged 4.2 per 1,000 population annually. Significant inverse correlations were observed between PM2.5 and FEV1 (r = -0.42, p < 0.001) and FVC (r = -0.38, p < 0.001). NO2 levels showed positive correlation with hospital admissions (r = 0.31, p = 0.004). High-exposure areas consistently exhibited poorer lung function and higher disease prevalence compared to low-exposure areas. Conclusion: Urban air pollution in Rawalpindi is strongly associated with adverse respiratory outcomes. The findings underscore the need for public health interventions, improved air quality monitoring, and policies aimed at reducing exposure, particularly among vulnerable populations. This review consolidates existing evidence to inform future research and targeted mitigation strategies.