Occupational exposure and personal exposure to hazardous air pollutants in underground metro stations and factors causing poor indoor air quality

AbstractIn this comprehensive research study, the occupational exposure levels of subway personnel employed in underground metro stations and personal exposure levels of passengers commuting by metro trains to airborne pollutants were investigated. The factors leading to deteriorating indoor air quality due to greater concentrations of air pollutants were also identified. For this reason, a field study was conducted in Chennai, India during both dry and wet climatic conditions. Indoor air pollutants, particulate matter (PM10, PM2.5, and PM1), total volatile organic compounds (TVOC), carbon dioxide (CO2), carbon monoxide (CO), bacteria, and fungi along with thermal indicators, temperature (T), relative humidity (RH), and air velocity (VA) were monitored in 7 underground metro stations and inside trains. The occupational exposure to PM, CO2, and CO were within the ACGIH-TLV limits, whereas, subway staff's exposure to PM10, PM2.5, TVOC, bacteria, and fungi was found to be 2 – 4 times higher than the recommended health-based safe exposure threshold limits set by WHO and ISHRAE. In contrast, passengers' exposure was 1.5 – 3 times higher than recommended limits for PM2.5, TVOC, and bacteria. An increase in PM10, PM2.5, and TVOC exposure concentrations up to 50  µg/m3, 15  µg/m3, and 30  ppb was observed, respectively in the metro stations due to the continuous operation of trains and the movement of passengers. In subway stations, exposure to fine airborne particles in the...
Source: Air Quality, Atmosphere and Health - Category: Environmental Health Source Type: research