Characterizing particulate polycyclic aromatic hydrocarbon emissions from diesel vehicles using a portable emissions measurement system

Abstract

Particulate polycyclic aromatic hydrocarbons (p-PAHs) emitted from diesel vehicles are of concern because of their significant health impacts. Laboratory tests, road tunnel and roadside experiments have been conducted to measure p-PAH emissions. While providing valuable information, these methods have limited capabilities of characterizing p-PAH emissions either from individual vehicles or under real-world conditions. We employed a portable emissions measurement (PEMS) to measure real-world emission factors of priority p-PAHs for diesel vehicles representative of an array of emission control technologies. The results indicated over 80% reduction in p-PAH emission factors comparing the China V and China II emission standard groups (113 μg kg−1 vs. 733 μg kg−1). The toxicity abatement in terms of Benzo[a]pyrene equivalent emissions was substantial because of the large reductions in highly toxic components. By assessing real traffic conditions, the p-PAH emission factors on freeways were lower than on local roads by 52% ± 24%. A significant correlation (R2~0.85) between the p-PAH and black carbon emissions was identified with a mass ratio of approximately 1/2000. A literature review indicated that diesel p-PAH emission factors varied widely by engine technology, measurement methods and conditions, and the molecular diagnostic ratio method for source apportionment should be used with great caution.

Seasonal analysis of submicron aerosol in Old Delhi using high resolution aerosol mass spectrometry: Chemical characterisation, source apportionment and new marker identification

“…Similar UnSubPAH and MPAH species in NHOA have been observed in laboratory studies measuring PAHs from diesel engines, but the ratios of these species largely depends on the mix of biodiesel and the running conditions of the engine (He et al, 2010;Tsai et al, 2011;Zheng et al, 2017). There is, however, a study which took place in Taj, India, which measured both indoor and outdoor PAH concentrations in homes along roadsides 655 or in residential areas.…”

Simultaneous measurement of multiple organic tracers in fine aerosols from biomass burning and fungal spores by HPLC-MS/MS

“…The LOD can be used to evaluate the sensitivity of the method, which was calculated as the concentration that corresponds to three times the standard deviation of the peak areas produced by lter blanks spiked with certain amount of standards. [71][72][73][74][75] In this study, to evaluate LODs, 20 mL of 2 mg L À1 standard solutions were spiked on blank lters to result in 10 mg L À1 of the standards in extracts. The LODs of these compounds range from 1.1 mg L À1 for levoglucosan to 3.8 mg L À1 for arabitol, as presented in Table 3.…”

A comparison of PM<sub>2.5</sub>-bound polycyclic aromatic hydrocarbons in summer Beijing (China) and Delhi (India)

“…The study from Liu et al, (2013) suggested that ambient temperature largely controls the gas-particle partitioning of 2, 3, and 4-ring PAHs concentration in the gas and particle phases. A number of molecular diagnostic ratios for source apportionment have been proposed in literature and are still under debate (Larsen and Baker., 2003;Katsoyiannis et al, 2011;Keyte et al, 2013;Zheng et al, 2017). They were considered uncertain in some studies because the results were not consistent and reproducible and did not reflect known differences in sources in space and time unless the source is very strong and the sampling measurements are made close to the known source.…”