Indoor Air Pollution and Respiratory Health in a Metropolitan City of Pakistan

Objective We assessed the association of formaldehyde, carbon monoxide (CO), and particulate matter (PM2.5) with respiratory symptoms, asthma, and post-bronchodilator reversibility. Methods We included 1629 adults in a community-based cross-sectional study in Karachi in 2015. Data were collected using the American Thoracic Society respiratory questionnaire and spirometry (available for 930 participants). YesAir eight-channel monitor was used for measuring concentrations of formaldehyde and CO, whereas PM2.5 was measured using UCB PATS. Results Higher levels of formaldehyde and CO were associated with cough, phlegm, and wheeze, whereas those of PM2.5 were associated with shortness of breath and presence of any of the respiratory symptoms (combined), as well as a "lower" risk of cough, phlegm, and bronchitis. Conclusion Poorer household air quality was associated with poorer respiratory health in this population; however, further studies with a robust exposure assessment are required.