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Cooking fumes are an important indoor source of polycyclic aromatic hydrocarbons (PAHs). Because indoor pollution has a more substantial impact on human health than outdoor pollution, PAHs from cooking fumes have drawn considerable attention. In this study, 16 PAHs emitted through deep-frying and frying methods using rapeseed, soybean, peanut, and olive oil were examined under a laboratory fume hood. Controlled experiments were conducted to collect gas- and particulate-phase PAHs emitted from the cooking oil fumes, and PAH concentrations were quantified via high-performance liquid chromatography (HPLC). The results show that deep-frying methods generate more PAHs and benzo[a]pyrene (B[a]P) (1.3 and 10.9 times, respectively) because they consume greater volumes of edible oil and involve higher oil temperatures relative to those of frying methods. In addition, the total B[a]Peq concentration of deep-frying is 2.2-fold larger than that of frying. Regarding the four types of edible oils studied, rapeseed oil produced more PAH emission than the other three oil varieties. For all of the cooking tests, three- and four-ringed PAHs were the main PAH components regardless of the food and oil used. Concerning the PAH partition between gas and particulate phase, the gaseous compounds accounted for 59-96 % of the total. Meanwhile, the particulate fraction was richer of high molecular weight PAHs (five-six rings). Deep-frying and frying were confirmed as important sources of PAH pollution in internal environments. The results of this study provide additional insights into the polluting features of PAHs produced via cooking activities in indoor environments.

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To study the emission characteristics of carbonyl compounds for in-use diesel vehicles on real roads, nine in-use heavyduty diesel trucks (HDDTs) representing different emission standards from China 0 to China 3 were tested on roads in Xiamen using an on-board carbonyl compound sampling system with a 2,4-DNPH cartridge. High-performance liquid chromatography (HPLC) was used to quantify the carbonyl compound emission factors. In total, 10 carbonyl compounds were detected for all the tested vehicles in this work. Formaldehyde, acetaldehyde and propanal were the three largest contributors of carbonyl emissions, accounting for 47.9%, 21.0% and 9.9% of the total carbonyls, respectively. The emission standards had a significant effect on the emission factors and profiles of the carbonyl compounds from the test vehicles. The total emissions of carbonyls from the test vehicles with China 0, China 1, China 2 and China 3 emission standards were 318.4, 232.8, 108.1 and 88.8 mg/km, respectively. The relative contribution of formaldehyde to the total carbonyl emissions increased with increasing stringency of the emission standards. Driving patterns also affected the vehicular carbonyl emissions. The total carbonyl emissions under highway driving cycles were lower than those under non-highway driving cycles. In addition, the ozone-formation potential of the carbonyls from the tested diesel vehicles was analyzed. This work represents a preliminary step in measuring carbonyl emission characteristics using portable emission measurement systems (PEMS). More attention should be paid to carbonyl emissions from HDDTs.