Characteristics and source apportionment of VOCs in the suburban area of Beijing, China

The measurement of volatile organic compounds (VOCs) was conducted during November 2014 in the suburban area of Beijing, China, covering the period of the Asia-Pacific Economic Cooperation (APEC) meeting period. The VOCs characteristics and source apportionment were analyzed. The average mass concentrations of VOCs were 27.6 ± 19.7 μg/m3 during the sampling period, and aromatics and alkanes were the most abundant VOCs species in atmospheric environment in Beijing which were 12.2 ± 10.3 μg/m3 and 11.3 ± 7.5 μg/m3, respectively. The hourly variation of VOCs was found, with the highest concentration occurring at 8:00 to 9:30 and lowest at 12:30 to 14:00. The sampling period was divided into two periods: period Ⅰ represent the period without emission-reduction measures, and period Ⅱ represent the period with reduction measures. The VOCs concentrations during the period Ⅱ was 31.0% lower than period Ⅰ. The Maximum Incremental Reactivity (MIR) method was applied to analysis the ozone formation potential (OFP). The OFP of VOCs from period Ⅰ was 1.6 times higher than period Ⅱ, and the majority of VOCs species were alkenes and aromatics. Positive matrix factorization was applied to estimate contributions of potential VOCs sources. The vehicle exhaust emission was the major source of VOCs during the two periods, and the contribution to VOCs was 5.7% lower during period Ⅱ than period Ⅰ due to the emission-reduction of vehicle operation.