In situ emission levels of polynuclear aromatic hydrocarbons from gasoline and diesel engine vehicles on an expressway

In situ emission levels of carcinogenic and mutagenic compounds from diesel and gasoline engine vehicles on an expressway

“…So, we neglected the effect of a contamination by incoming air including the particles. Sampling equipment and procedures in both the tunnels were basically the same and have been described in detail in our previous paper (16).…”

“…Their rates were 0.49 (41.2) and 0.03 (2.52) pg/km (pg/h) for the diesel and gasoline engines, respectively, so then the emission ratio of the diesels to the gasolines was ca. 16. In addition, the 1-nitropyrene concentrations (ppm) in the CH2Cl2 extract from filter samples were 2.1 and 5.0 for the diesel and gasoline engines, respectively.…”

“…We have reported previously on in situ emission levels of PAHs from diesel and gasoline engine vehicles on an expressway (16). It was found that the average emission rates fag/h) per vehicle of PAHs from light-duty gasoline engine cars were about 2-3 times higher than those from heavy-duty diesel engine vehicles under the relatively high-load condition of the average ascending road slope of 0.4%, even when the differences in average exhaust volume between both engines were considered.…”

The fate of airborne polycyclic organic matter.

“…A substantial part of the low molecular weight PAH are present in vapor phase in the atmosphere (15,(43)(44)(45)(46). Subsequent reactions of vapor-phase PAH and other arenes with hydroxyl radicals and nitrogen dioxide may perhaps be a source for their transformation to nitro-derivatives under conditions of photochemical air pollution during the day.…”

“…This suggests, however, that particle-bonded PAH is not associated exclusively with carbonaceous particles. This point may perhaps be more important for the lower PAH (four rings) considering the difference in the particle-size distribution for the lower and higher PAH in diluted exhaust gas (133) and the substantial amount of the lower PAH in the atmosphere occurring in vapor phases (15,(43)(44)(45)(46).…”