NANOPARTICLES SIZE DISTRIBUTION IN THE EXHAUST EMISSIONS OF DIESEL AND CNG BUSES

Motor vehicles are the most important sources of gaseous and particulate matter emission in urban areas with the serious health effects which cause the respiratory and cardiovascular diseases and mortality. Motor vehicles emit a broad range of PM from 0.003 to 10 μm.
The exhaust emission of BRT and diesel buses was samples by portable environmental dust monitor, model EDM 107 during summer and winter 2016. ANOVA was applied at a significant level (Pvalue The lowest concentration of emission was seen in BRT buses and the average number of particles in every liter of exhaust sample was 776330 ± 40428. The amount of emission from BRT buses in winter was 166217 ± 971870. There is a significant difference between total emissions of nanoparticles releasing by diesel and BRT buses in each season, but there isn’t any significant difference between the emissions of nanoparticles releasing by diesel buses in summer and winter.
There was the high emission of particles emitted by diesel buses in both seasons. Since the impacts of particulate matters on health should be considered in Tehran, planning the best locations for bus terminals and also monitoring these places continuously are recommended.