第八届青年地学论坛

    Vehicle exhaust and fuel evaporation both emitted volatile organic compounds (VOCs). In practice, diversities in cocktail source profiles (CSP) of VOCs with tunnel test and the calculated composite profiles (CCP) with single vehicle exhaust test have been less addressed. VOC samples were collected in a tunnel of a city center, from vehicle exhaust, and from fuel evaporation in gas stations, respectively. 107 kinds of VOCs were analyzed. Results showed that gasoline burning led to reduction of alkene, from 53.1% of gasoline evaporation to 3.6% of gasoline exhaust. Ethane and cis-2-butene were dominant components that resulted in differences between gasoline evaporation and gasoline exhaust. Alkenes increased after diesel burning, from 1.3% to 34.0%. Higher aromatics of diesel evaporation were caused by m/p-xylene (20.3%) and o-xylene (9.9%). CCP could not better represent CSP, with a coefficient of divergence of 0.6. Ethane, ethylene, n-undecane, and n-dodecane were species distinguished by gasoline and diesel exhaust. Cis-2-butene, 2-methylpentane, m/p-xylene, o-xylene, and n-decane were key tracers to distinguish gasoline and diesel evaporation. For diagnostic ratios, xylene/ethylbenzene and i-butane/n-butane ratios were suitable for source apportionment when CCP was used, while toluene/benzene and i-pentane/n-pentane ratios were not appropriate. Fuel burning led to an increase in health risks than fuel evaporation. Ethylene (16.6%–47.2%) and m/p-xylene (6.2%–20.6%) were dominant ozone potential formation (OFP) species. Oil burning led to a change of alkenes to OFP, decreased from 88.0% of gasoline evaporation to 19.2% of gasoline exhaust, and increased from 3.2% of diesel evaporation to 76.3% of diesel exhaust. Toluene (28.1% and 17.4%) and m/p-xylene (16.2% and 21.1%) were dominant secondary organic aerosol potential species from CSP and CCP. This study can provide a reference for obtaining VOC source profiles of sub-sector emission sources and the datasets are helpful for refined VOC source apportionment and speciated emission inventory studies.
 

Volatile organic compounds; Composite emission; Tunnel test; Gasoline and diesel vehicle exhaust; Diesel and gasoline evaporation