Mass Concentration, Source and Health Risk Assessment of Volatile Organic Compounds in Nine Cities of Northeast China

Sources and environmental impacts of volatile organic components in a street canyon: Implication for vehicle emission

Street canyons serve as a representative environment that directly reflects the impact of vehicular emissions. Volatile organic compounds (VOCs) sampling during an O3 pollution event and a PM2.5 pollution episode was conducted at an urban site and a street canyon in Zhengzhou, China. It has been determined that street canyons suffer from more severe particle and NOx pollution than the urban site. Additionally, O3 has been identified as a significant or emerging pollutant in street canyon environments. In terms of VOCs, the street canyon exhibits 1.4 and 1.1 times higher total VOC concentrations compared to the urban site during the O3 and PM2.5 pollution episodes, respectively. In the street canyon location, there was a slight increase in the proportion of alkanes and aromatics, while the proportions of oxygenated VOCs and halogenated hydrocarbons decreased. Source apportionment analysis reveals that street canyons were more susceptible to the accumulation of VOCs from coating solvent, liquid petroleum gas (LPG), and gasoline additives. Consequently, the environmental impacts of VOCs originating from coating solvent and LPG were more pronounced in the street canyon location compared to the urban site. The trends of NOx concentration indicate that future continuously stricter vehicle emission standards and control policies can further reduce vehicle exhaust emissions and more attention needs to be focused on the reduction of non-exhaust emissions (i.e., coating solvent) and LPG vehicles.

Distribution of Hydrocarbons in the Snow Cover of Natural and Urbanized Landscapes in the South of the Far East, Russia

This study analyzed total organic carbon (TOC), petroleum products (PP), suspended materials (SM), volatile aromatic hydrocarbons (toluene, o-xylene, etc.) and n-alkanes in the snow cover of Bol'shekhekhtsirsky, Zeysky state natural reserves and Khabarovsk, on 4, 5 and 9 stations in the south of the Russian Far East in March 2020. In Bol'shekhekhtsirsky reserve, the concentrations of TOC, PP, and SM in snow samples were in the range of 1.5-2.4, 0.06-0.11, and 11.4-1.9 mg/L, 1.4-1.9, 0.02-0.05, and 11-23 mg/L in Zeysky reserve, while in Khabarovsk were 1.7-23.7, 0.12-1.26, and 25-294 mg/L, respectively. In addition, the benzene, toluene, and o-xylene concentrations of snow samples ranges from not detected (ND) to 2.4, ND-3.1, and 1.1-2.7 µg/L in Khabarovsk, ND-1.3, ND-2.1, and ND-2.7 µg/L, respectively in Bol'shekhekhtsirsky reserve. Carbon preference index values of n-alkanes were consistent with anthropogenic sources for stations 7, 8 and 2 in Khabarovsk (Heat Power Plants 1, 2 and city roads). The snow of the Zeysky Reserve is not contaminated with organic pollutants, and can be used as a conditional background for the south of the Russian Far East.