Establishment of an Air-Quality Indicator for Bus Diesel Exhaust in Garages

This study simultaneously measured levels of CO2, CO, NO, NO2, and total particulates in three bus garages of a mass transit company, using standard methods. Statistically significant (p approximate to 0.0000) multiple correlations (r = 0.547 to r = 0.805) were found between contaminants and predictors such as CO2 or type of garage. A net CO2 concentration of 400 ppm can therefore be proposed as an indicator of the maintenance of air quality in these garages. While the specific relationship between CO2 levels will vary as a function of operating conditions in specific garages, this approach can nevertheless serve as the basis of air-quality monitoring in other garages where diesel engines are in operation.