Investigating Air Pollution Exposures in a Cohort of Traffic Police in Kathmandu, Nepal

摘要

Exposure to traffic pollution has been generally accepted to be deleterious to human health. Much of our understanding of this stems from studies performed in developed nations, where emissions controls are reasonable and overall pollutant loading is relatively low. However, much of the world is subjected to substantially different aerosol conditions, particularly in developing nations. Six Nepali traffic police officers at six different locations (total cohort size: 36 unique individuals) were monitored for 6 consecutive days each with a suite of monitors including a personal scattering nephelometer, a micro aethalometer, a GPS record, and an accelerometer measure of activity. 24 hour integrated filters were also collected for chemical speciation, including trace metals, organic and elemental carbon, and ions. Five-minute averaged levels observed in Kathmandu were varied with typical exposure levels during their work shifts between 1000-2000 μg m-3, which were sustained for 6-10 hours; background concentrations rarely dropped below 20-25 μg m-3. Black carbon levels were equally variable, with observed five-minute averaged concentrations typically between 5 and 300 ugC m-3. Passive sampling of gas phase species was also performed. A number of health endpoints were measured in individuals including pre and post shift blood pressure and spirometry, 96 hours of electrocardiogram, and 3 and 4 samples, respectively, of blood and urine biomarkers for measures of inflammation and oxidative stress. An intervention was included in the study design which provided N95 personal face masks for participants to wear for part of their work week to reduce occupational exposures to traffic generated particulate matter.