Abstract
BACKGROUND: The World Health Organization (WHO) global air quality study shows that 27 Indian cities, including New Delhi, are among the one hundred cities with the worst air quality globally. The scope of airway obstruction cases among residents in locations with critical air pollution levels like particulate matter (PM) pollutants PM(2.5) and PM(1) has not been addressed in the National Capital region, India. OBJECTIVES: The present cross-sectional study was undertaken to assess the forced expiratory volume in one second (FEV(1)) % predicted abnormalities among residents living in the National Capital Region, India with respect to their exposure to particulate matter pollutants (PM(1), PM(2.5)) in ambient air. METHODS: Eight hundred and fifty-four residents, including 433 men and 421 women ranging in age from 18-70 years, living in the National Capital Region (NCR) of India participated in the study. Particulate matter concentrations in ambient air (PM(2.5) and PM(1)) were monitored at 10 residential locations in the National Capital Region, India (New Okhla Industrial Development Authority (NOIDA) and Gurgaon). The lung function test (FEV(1)) was conducted using a spirometer. RESULTS: The Indian Air Quality Index showed either very poor or severe levels for PM(2.5) at all study locations. A significant negative linear relationship was found between higher concentrations of PM(1) and reduced FEV(1)% predicted values (r = -0.8, p < 0.05). The prevalence of airway obstruction cases (79.6%, odds ratio 1.96, confidence interval 1.42-2.71) was higher (p<0.001) among female subjects compared to their male counterparts. Even though there was a significant decline in FEV(1)% predicted among 80% of cases in women, only 19.24% cases were in the moderate category and 6.18% cases in the severe category. The severe category of FEV(1)% predicted cases showed greater respiratory symptoms than the other two categories, which denotes higher risk among those in the severe category. The present study shows that obstruction cases increased from 1.97 to 7.40% and 2.73 to 14.93% in women, with a corresponding increase in PM(1) and PM(2.5) from the minimum to maximum concentration. CONCLUSIONS: Since the women in this study were non-smokers, the PM in ambient air can be considered to be the major reason for the decline in lung function. The sources of PM pollutants in the study locations are large scale infrastructural development activities such as building and road construction activities. Narrowed lung airways can alter the airway caliber or resistance and flow rates proportional to the airway radius, especially in smaller airways. The present study suggests the need for policy makers and stake holders to take the necessary steps to identify PM sources and reduce the emissions of PM concentrations in ambient air.