Benzene and Toluene in the surface air of North Eurasia from TROICA-12 campaign along the Trans-Siberian railway

Other literature type English OPEN
Skorokhod, Andrey I. ; Berezina, Elena V. ; Moiseenko, Konstantin B. ; Elansky, Nikolai F. ; Belikov, Igor B. (2016)

Volatile organic compounds (VOCs) were measured by proton transfer reaction – mass spectrometry (PTR-MS) on a mobile laboratory in a transcontinental TROICA-12 (21.07.2008–04.08.2008) campaign along the Trans-Siberian railway from Moscow to Vladivostok. Surface concentrations of benzene (C<sub>6</sub>H<sub>6</sub>) and toluene (C<sub>7</sub>H<sub>8</sub>) along with non-methane hydrocarbons (NMHCs), CO, O<sub>3</sub>, SO<sub>2</sub>, NO, NO<sub>2</sub> and meteorology are analyzed in this study to identify the main sources of benzene and toluene along the Trans-Siberian railway. The most measurements in the TROICA-12 campaign were conducted under low-wind/stagnant conditions in moderately (~&thinsp;78&thinsp;% of measurements) to weakly polluted (~&thinsp;20&thinsp;% of measurements) air directly affected by regional anthropogenic sources adjacent to the railroad. Only 2&thinsp;% of measurements were identified as characteristic of highly polluted urban atmosphere. Maximum values of benzene and toluene during the campaign reached 36.5&thinsp;ppb and 45.6&thinsp;ppb, correspondingly, which is significantly less than their one-time maximum permissible concentrations (94 and 159&thinsp;ppb for benzene and toluene, correspondingly). About 90&thinsp;% of benzene and 65&thinsp;% of toluene content is attributed to motor vehicle transport and 10&thinsp;% and 20&thinsp;%, correspondingly, provided by the other local and regional-scale sources. The highest average concentrations of benzene and toluene are measured in the industrial regions of the European Russia (up to 0.3 and 0.4&thinsp;ppb for benzene and toluene, correspondingly) and south Siberia (up to 0.2 and 0.4&thinsp;ppb for benzene and toluene, correspondingly). Total contribution of benzene and toluene to photochemical ozone production along the Trans-Siberian railway is about 16&thinsp;% compared to the most abundant biogenic VOC – isoprene. This contribution, however, is found to be substantially higher (up to 60–70&thinsp;%) in urbanized areas along the railroad suggesting important role of anthropogenic pollutant sources in regional ozone photochemistry and air quality.
Share - Bookmark