Ambient Air Quality Assessment and Respiratory Health Outcomes in Urban and Industrial Zones

Rapid urbanisation and industrial expansion in Maharashtra have contributed to persistent deterioration of ambient air quality, generating measurable adverse respiratory health outcomes in exposed populations. This study presents a systematic assessment of six key air pollutants — PM2.5, PM10, NO2, SO2, CO, and ground-level ozone — measured across thirty monitoring stations in Pune, Mumbai, and Nagpur Metropolitan Regions over a twenty-four-month continuous monitoring period. Simultaneously, respiratory morbidity data including incidence rates of asthma exacerbation, chronic obstructive pulmonary disease hospitalisations, and upper respiratory tract infection consultations were extracted from district health records for the same temporal and spatial frame.Industrial zone monitoring stations recorded PM2.5 levels averaging 124.6 μg/m³, exceeding the WHO annual guideline of 15 μg/m³ by more than eightfold. Urban residential zones recorded lower but still severely elevated levels of 87.4 μg/m³. Distributed lag non-linear model analysis identified a significant lagged association between PM2.5 and PM10 concentrations and respiratory hospital admissions at lags of two to seven days. Every 10 μg/m³ increase in PM2.5 was associated with a 6.8 percent increase in asthma emergency department visits (95% CI 5.2-8.4%) and a 4.3 percent increase in COPD exacerbation hospitalisations (95% CI 3.1-5.5%). The Italian collaborative team's contribution validated the spatiotemporal interpolation methodology using kriging models previously applied in northern Italian industrial corridors.