Affiliations: Department of Environmental Science, Zhejiang
University, Hangzhou 310028, China | Environmental Monitoring Centre, Hangzhou 310012,
China
Abstract: PAHs pollution in air of arterial roads was investigated from
October 1998 to October 2001 in Hangzhou, China. The results showed that
Σ10 PAHs was 13–36 μg/m3 , among which, BaP, a strong
carcinogenic kind ranged from 0.034 μg/m^3 to 0.12
μg/m^3. PAHs pollutions in four seasons were winter >
autumn > spring-summer. The annual averages of ΣPAHs concentration
were 25 μg/m^3 for 1999, 28 μg/m^3
for 2000, and 29 μg/m^3 for 2001, respectively. Leaded
gasoline was banned in December 1998 in Hangzhou, thus comparative measurements
with PAHs in leaded and lead-free gasoline powered motor exhausts made it
certain that the use of lead-free gasoline leaded to a heavier PAHs pollution
in roadside air from December, 1998, in China, and ΣPAHs in air samples
after the lead-banning were more than twice of that in samples before the
action. For the large contribution of vehicle discharge to air pollution in
roadside, further research was performed to suggest the factors influencing
PAHs distribution in vehicle exhaust in order to control air pollution
effectively. Compared to gasoline engines, emissions from diesel engines were
less toxic, although they might produce more PAHs. Of the same vehicular and
oil type, automobiles of longer mileages produced more toxic PAHs. PAHs
distributions in the vehicular exhausts were related to the oil type. Large
difference was found in the abundance of 3-, 5- and 6-ring PAHs between
exhausts from gasoline and diesel oil engines. Diesel oil engines produced
relative lighter PAHs such as NAPH, ACEN, FLUOR, while gasoline engines emitted
heavier kinds such as BkF, IN and BP. The automobile produced more PAHs with
the increase of mileage especially FLUR, PY, BaP, BP. Some significant ratios
for traffic source in Hangzhou such as PHEN/AN, FLUR/PY, IN/BP were
0.50–4.3, 0.58–7.4, 0.51–1.5, respectively. A source
fingerprint for vehicle exhausts of a mixture of vehicle and oil types in the
city district for light-duty vehicle was the abundance of BaA, followed by
NAPH, BP, IN. 4-ring PAHs such as FLUR, PY, BaA and CHRY were the most
predominant kindsfollowed by 6-ring PAHs (BP, IN).
Keywords: PAHs, influencing factors, vehicle exhaust, air pollution
