利用HYSPLIT模型研究珠三角地区VOCs时空分布特征

于2016年在中国广东大气超级监测站，开展4个季节的VOCs长时间观测，共获得2142组有效数据，并利用HYSPLIT模型分析珠三角地区VOCs时空分布特征.结果表明，各类VOCs混合比和化学反应活性具有明显的季节变化特点.观测期间，VOCs平均浓度为（18.523±20.978）×10^-9，其中，低碳烯烃和苯系物二者混合比之和仅占46%，但贡献了85%的·OH消耗速率（L_OH）、82%的臭氧生成潜势（OFP）和97%的二次气溶胶生成潜势（SOAFP）.观测站点主要受来自北部内陆地区气团（1#）、西部内陆地区气团（2#）、台湾海峡南端气团（3#）以及南部海洋地区气团（4#）的影响.1#气团中炔烃和苯系物的混合比占比最高，分别达到10%、37%，而3#气团中低碳烷烃的浓度水平最高，达到（8.437±5.561）×10^-9.通过估算气团中VOCs的化学反应活性，可以发现，1#气团的VOCs化学反应活性最强，其对O₃和SOA的生成贡献最高.1#、2#、3#和4#气团中VOCs的化学反应活性主要由苯系物和低碳烯烃贡献.

Spatial and temporal distribution characteristics of VOCs in the Pearl River Delta region using HYSPLIT model

Based on the long time observation of VOCs at Guangdong Atmospheric Supersite (GAS) in the four seasons of 2016, 2142 sets of valid data were obtained. Using HYSPLIT model, the spatial and temporal distribution characteristics of VOCs in the Pearl River Delta region were analyzed. Mixing ratios and chemical reactivities of VOCs had obvious seasonal variation characteristics. The average concentration of VOCs was (18.523±20.978)×10^-9 during the observation period. Though the mixing ratios of C2~C5 alkenes and BTEX accounted for only 46%, they contributed 85% of·OH loss rate (L_OH)、82% of Ozone Formation Potential (OFP) and 97% of Secondary Oragnic Aerosol Formation Potential (SOAFP). The observation sites were mainly affected by the air masses from the northern inland areas (1#), the western inland areas (2#), the southern tip of the Taiwan Strait (3#) and the southern marine areas (4#). The mixing ratios of alkynes and BTEX of 1# air masses were both the highest, respectively, 10% and 37%, and the concentration of C2~C5 alkanes of 3# air masses was the highest, reaching (8.437±5.561)×10^-9. By estimating the chemical reactivities of VOCs of air masses, it was found that the chemical reactivities of VOCs of 1# air masses were the strongest, and their contributions to O₃ and SOA production were the highest. The chemical reactivities of VOCs of air masses of 1#, 2#, 3# and 4# were mainly contributed by BTEX and C2~C5 alkenes.