Ambient volatile organic compound presence in the highly urbanized city: source apportionment and emission position

Ambient volatile organic compounds (VOCs) measured hourly by the photochemical assessment monitoring station (PAMS) in Taichung were collected to analyze characteristics and provide source apportionment of VOCs. In this study, aromatics and alkanes were found to be the major VOC categories. The major species included toluene, m,p-xylene, propane, ethane, n-butane, and isopentane, which came from the east and southeast. VOC concentrations were highest in March and lowest in July, due to temperature, accumulated precipitation, boundary layer effects, and photochemical reactions. Positive matrix factorization analysis showed that industrial emissions (solvent usage and industry) were the major source, which originated from the northwest to south. Traffic emissions (fuel evaporation and vehicular emissions) were the second highest source and came from the southeast. An estimation of ozone formation suggests that industrial emissions were still a key source. Therefore, effective abatement strategies for industrial emissions should be given priority for VOC control.