Hazardous volatile organic compounds (HVOCs) have been increasingly getting concern in urban air chemistry due to photochemical smog as well as its toxicity or potential hazards. In this study, we investigated their concentrations and the properties in tunnel, urban roadside and residential area. As a result, among 36HVOCs measured in this study, BTEX (benzene, toluene, ethylbenzene, xylene) and dichlorodifluoromethane, 1,2,4-trimethylbenzene, trichlorofluoromethane were detected above the concentration of 1 μg/m 3 in every sampling site and the most abundant compound was toluene. The other compounds were detected at trace level or below the detection limit. In addition, we found that three CFCs (chlorofluorocarbons), such as CFC-12, CFC-11, CFC-113, were persistently detected because of the emission in the past. Toluene to benzene ratio (T/B) at tunnel and roadside were calculated to be 4.35 .3 and at residential area 15.4, suggesting that the residential area had several emission sources other than car exhaust. The ratio of X/E (m,p-xylene to ethylbenzene) ratio was calculated to be 1.8~2.1 at tunnel, 1.7 at roadside and 1.2 at residential area, which means this ratio reflected well the relative photochemical reactivity between these compounds. Good correlation between m,p-xylene and ethylbenzene (r 2 ¤0.85) were shown in every study sites. This indicated that correlation between C 2 -alkylbenzenes were not severely affected by 3-way catalytic converter. In this study, it was demonstrated that the concentration of benzene was very low, compared with national air quality standard (annual average of 5 μg/m 3 ). Its concentration were 2.52 μg/m 3 in roadside and 1.34 μg/m 3 in residential area. We thought this was the result of persistent policy implementation including the reduction of benzene content in gasoline enforced on January 1, 2009.

Personal air exposure to monocyclic aromatic amines (MAA) is a growing concern, in large part, due to their ubiquitous presence in the general environment and their potential health risk for bladder cancer. It is unclear what other sources of airborne MAA are for general population, due to low concentrations in the air. Detecting "trace" levels of MAAs requires a sensitive analytical method and field evaluation. In this study, an analytical method was developed to detect 2,3-dimethylaniline [2,3-DMA]; 3,5-DMA; and 3-ethylaniline [3-EA] in general air environment. During a 12-hr sampling periods, the estimated limit of quantifications (LOQs) were less than 4.13 ng/m 3 for 2,3-DMA; 3,5-DMA; and 3-EA. Desorption efficiencies (recovery rates) were at least 89% with 1 ng of each 2,3-DMA; 3,5-DMA; and 3-EA per tube. The storage effect for three MAAs showed that all three MAAs remained above 60% on the sorbent tubes and filters over 10 days. A field study was conducted in Seoul, Korea to validate sampling method in a real-world busy street with traffic, an office near the same street, and a residential home away from the busy street. Gas-phase 2,3-DMA was detected only in the indoor home sample (3.26±0.60 ng/m 3 ), and 3,5-DMA was not detected in all samples. Particle-bound 3-EA was detected in the street (10.92±4.73 ng/m 3 ), office (9.47±6.11 ng/m 3 ), and residential home (7.53±4.17 ng/m 3 ). The results suggested that the proposed analytical and field sampling methods can useful for environmental exposure assessment of these MAAs.