应用WRF/Chem模拟河南冬季大气颗粒物的区域输送特征

基于WRF/Chem模式,设置多组区域排放源的情景实验定量估算河南、京津冀、山东、山西、安徽和江苏、湖北6个区域人为源排放对河南省2015年12月PM_(2.5)和PM_(10)浓度贡献率,并结合气象资料研究3个代表性城市的污染输送特征.结果表明:河南省冬季PM_(2.5)和PM_(10)主要来源为本省排放,平均贡献率分别为54.83%、61.32%.区域污染输送对河南颗粒物的贡献也占有很大比例,京津冀、安徽和江苏、山东、山西以及湖北对PM_(2.5)平均贡献率分别为11.95%、11.69%、7.95%、7.40%、4.30%,对PM_(10)平均贡献率分别为10.42%、10.03%、7.00%、6.89%、3.80%.PM_(2.5)外来输送率比PM_(10)要高,表明细颗粒物比粗颗粒物更易跨区域长距离输送.冬季长持续时间的污染过程大多受静风或小风控制,省内污染贡献最大,过程结束时伴随着大风,周边区域的污染贡献有所增加.不同城市的颗粒物来源与其地理位置、风速、风向等气象条件密切相关.区域污染来源具有复杂性,改善河南省空气质量是需要整个区域共同面对和解决的问题.

Simulation for the impacts of regional transport on winter particulate matter levels over Henan based on WRF/Chem model

Based on WRF/Chem model, scenario analysis on regional emission were conducted to quantitatively estimate the anthropogenic source contribution ratio from Henan, Beijing-Tianjin-Hebei,Shandong, Shanxi, Anhui, Jiangsu and Hubei to the ambient PM_2.5 and PM₁₀ concentrations of Henan in December 2015. Characteristics of pollution transport in three representative cities were analyzed in combination with meteorological data. The result shows that the main source of PM_2.5 and PM₁₀ in winter is local emission within Henan, with an average contribution ratio of 54.83% and 61.32%, respectively. Regional pollution transport also contributes to particulate matter in Henan, with the averaged contribution ratio of 11.95%, 11.69%,7.95%, 7.40% and 4.30% for PM_2.5 and 10.42%, 10.03%, 7.00%, 6.89% and 3.80% for PM₁₀ from Beijing-Tianjin-Hebei, Anhui and Jiangsu, Shandong, Shanxi and Hubei, respectively. Region transport ratio of PM_2.5 is higher than that of PM₁₀, which indicates that fine particulate matter is more likely to have long range transport than coarse one. In winter, the long-duration pollution process is mostly controlled by calm or weak wind and the most pollution contribution is from within the province.The process ends by strong wind, and regional contribution increases. The origins of particulates in different cities have a close relationship with their geographic location and meteorological condition such as wind. Regional pollution sources are complex, thus regional pollution co-prevention and co-control is needed to improve air quality in Henan province.