Long-term lung function decline from chronic workplace exposure in roadside vendors of Peshawar, Pakistan

Air pollution is a leading global public health challenge, with PM2.5 exposure strongly associated with respiratory and cardiovascular morbidity. In developing countries like Pakistan, urban air pollution levels are particularly severe. In 2021, Peshawar was ranked 9th globally for pollution, with PM2.5 levels 12 to 16 times higher than WHO limits. This study investigates chronic exposure to heavy traffic emissions and its long-term effects on lung function in Peshawar's roadside vendors, a highly exposed occupational group from an under-reported location.

A cross-sectional study was conducted on 218 non-smoker male roadside vendors in Peshawar. Spirometry assessed FEV1, FVC, PEF, and FEV1/FVC ratio against GLI-predicted values adjusted for age and BMI. Duration of work and daily exposure hours were documented. Ground-based PM2.5 data (2019-March 2025) were recorded separately. Analysis was performed in SPSS using multivariate linear regression models.

PM2.5 remained consistently high (mean range: 139-166 μg/m³) from 2019-2025, with notable occasional spikes observed. All spirometric indices declined with increasing exposure duration. Regression showed each additional year reduced GLI-predicted %FEV1 by 0.3 % (p=0.042) and %PEF by % 0.47 (p=0.018). Descriptive statistics showed the >20-year exposure group had the lowest GLI-predicted % means for FEV1, FVC, FEV1/FVC and PEF values. Normal spirometry predominated, but restrictive and obstructive patterns were also observed in earlier exposure groups.

Prolonged roadside air pollution exposure progressively impairs lung function, underscoring the urgent need for occupational and environmental public health interventions to safeguard high-risk informal workers.