Occupational exposure to air pollution and respiratory health among urban street vendors in South India

Background Street vending is a non-formal, vital domestic workforce in most developing nations. The street vendors operate in an unregulated environment and are frequently exposed to hazardous environmental pollutants, which is linked to chronic respiratory health problems. However, there is underreporting of this public health problem in literature, creating a blind spot in global health. Objective To assess the association between air quality, occupational exposure characteristics, and pulmonary function among street vendors in an urban community. Methods A cross-sectional study was conducted among 298 street vendors in Chennai city, India. Pulmonary function was assessed using peak expiratory flow rate (PEFR) and breath-holding time (BHT). Respiratory symptoms were evaluated using the Modified Borg Dyspnea Scale. Air quality was measured using the Air Quality Index (AQI). Linear regression analysis identified independent predictors of PEFR. Results The mean age of participants was 38.5 ± 11.08 years, with 65.4% female. Mean PEFR was 376.1 ± 71.39 L/min, and BHT was 33.32 ± 9.07 seconds. High prevalence of respiratory symptoms was observed: coughing at work (58.7%) and morning phlegm (44%). Significant negative predictors of PEFR included years working as a vendor (β=-3.34, p < 0.001), daily outdoor exposure hours (β=-6.48, p < 0.001), annual AQI (β=-1.80, p = 0.002), weight (β=-1.19, p < 0.001), and dyspnea at rest. BHT showed a strong positive association with PEFR (β = 3.03, p < 0.001). Only 2.3% of vendors reported using masks during work. Conclusion Street vendors demonstrate measurable respiratory compromise associated with cumulative occupational exposure to air pollution. Long-term exposure metrics (annual AQI, years of work) were stronger predictors than short-term measures, emphasizing the chronic nature of occupational health risk. Findings underscore the need for targeted respiratory screening, awareness programs, and feasible protective interventions for this vulnerable informal workforce.