Ambient levels of volatile organic compounds in the vicinity of petrochemical industrial area of Yokohama, Japan

Urban ambient air concentrations of 39 aromatic (including benzene, toluene, and xylenes) and aliphatic volatile organic compounds (VOCs) were measured in Yokohama city, Japan. Yokohama city was selected as a case study to assess the amount of VOC released from Industrial area to characterize the ambient air quality with respect to VOC as well as to know the impact of petrochemical storage facilities on local air quality. For this purpose, ambient air samples were collected (from June 2007 to November 2008) at six selected locations which are designated as industrial, residential, or commercial areas. To find out the diurnal variations of VOC, hourly nighttime sampling was carried out for three nights at one of the industrial locations (Shiohama). Samples were analyzed using gas chromatographic system (GC-FID). Results show strong variation between day and nighttime concentrations and among the seasons. Aliphatic fractions were most abundant, suggesting petrochemical storage facilities as the major source of atmospheric hydrocarbons. High concentrations of benzene, toluene, ethyl benzene, and xylene (BTEX) were observed at industrial locations. BTEX showed strong diurnal variation which is attributed to change in meteorology. During our campaign, low ambient VOC concentrations were observed at the residential site.