Source apportionment of VOCs and the contribution to photochemical ozone formation during summer in the typical industrial area in the Yangtze River Delta, China

摘要

Volatile organic compounds (VOCs) were continuously observated in a northern suburb of Nanjing, a typical industrial area in the Yangtze River Delta, in a summer observation period from 15th May to 31st August 2013. The average concentration of total VOCs was (34.40 +/- 25.20) ppbv, including alkanes (14.98 +/- 12,72) ppbv, alkenes (7.35 +/- 5.93) ppbv, aromatics (9.06 +/- 6.64) ppbv and alkynes (3.02 +/- 2.01) ppbv, respectively. Source apportionment via Positive Matrix Factorization was conducted, and six major sources of VOCs were identified. The industry-related sources, including industrial emissions and industrial solvent usage, occupied the highest proportion, accounting for about 51.26% of the VOCs. Vehicular emissions occupied the second highest proportion, accounting for about 34.08%. The rest accounted for about 14.66%, including vegetation emission and liquefied petroleum gasatural gas usage. Contributions of VOCs to photochemical O-3 formation were evaluated by the application of a detailed chemical mechanism model (NCAR MM). Alkenes were the dominant contributors to the O-3 photochemical production, followed by aromatics and alkanes. Alkynes had a very small impact on photochemical O-3 formation. Based on the outcomes of the source apportionment, a sensitivity analysis of relative O-3 reduction efficiency (RORE), under different source removal regimes such as using the reduction of VOCs from 10% to 100% as input, was conducted. The RORE was the highest (similar to 20%-40%) when the VOCs from solvent-related sources decreased by 40%. The highest RORE values for vegetation emissions, industrial emissions, vehicle exhaust, and LPG/NG usage were presented in the scenarios of 50%, 80%, 40% and 40%, respectively. (C) 2016 Elsevier B.V. All rights reserved.