Objectives: To investigate the traffic-related PM2.5 and black carbon (BC)
exposures and assess their health effects. Methods: Personal exposure to
PM2.5 and BC levels were monitored in a cohort of traffic police (n ¼ 53) at
six locations in Kathmandu Valley, Nepal during dry and rainy seasons in
2014. Results: Mean on-road exposure levels of PM2.5 and BC ranged from
34 to 193mg/m3 and 12 to 28mgC/m3
, respectively, and were associated with
an acute decline in lung function. Use of N95 mask had clear benefits
reducing the lung function decreases after occupational exposures when
masks were worn for just half of a workweek. Conclusions: Exposure of
high levels of PM2.5 was associated with reduced lung function. Increased
levels of BC exposure led to reduced lung function in non-smoking traffic
officers with non-normal spirometry observations.