Source Apportionment Of Fine Particles In The Yang River Delta Region In Winter Season Based On Air Quality Simulation

In recent years, with the development of industrialization and urbanization, energyconsumption and possession quantity of mobile vehicles are increasing continuously in our country.Meanwhile, air pollution issues become more and more prominent, especially for fine particles,which is the representative of air pollution complex, has become a significant problem restrictingurban and economic development. The urgent task for alleviating and controlling current seriouspollution is to adopt scientific and effective emission-reduction policies, which then requires quickdiagnosis and identification of fine particle major regions and emission sources through scientificmethods.In this research, based on the highly resolved emission inventory of Yangtze Delta region,PSAT technology coupled with WRF-CAMx modeling is adopted to study contributions from26cities in Yangtze River Delta and9major emission sectors to urban fine particles. In addition, sourceapportionment is also studied for urban fine particles and their major components (including sulfates,nitrates, ammonia, element carbon and organic carbon) in the major cities (Shanghai, Hangzhou,Nanjing, Hefei and so on).Though analyzing the whole pollution situation during December2013in Yangtze Delta, fourtypical episodes were choosed: fog and haze episode from December5to7, haze episode fromDecember11to14, transit haze episode from December25to26, and comparably clean episodefrom December21to23. The comparison result shows that, under the impact of dominant northwestwind in Yangtze Delta during December2013, super-regional transport had a bigger influence onPM2.5concentration in northern Jiangsu Province. However, for cities located in borders of JiangsuProvince, Zhejiang Province and Shanghai in central of Yangtze River Delta, and also cities located in south central of Zhejiang Province, fine particles were affected by local emissions more obviously.Under the adverse weather conditions in winter, slight transports between adjacent cities wasdominant in urban fine particle transport in Yangtze River Delta. Under favorable diffusioncondition, obvious transport channel was formed, affected by dominant wind direction, and citiesin upwind directions transported particles to cities in downwind directions, which means thatregional transport between cities was dominant.Industrial source (including process engineering, industrial boiler and furnace) was the largestfine particle emission source in Yangtze River Delta, followed by fugitive dust which was a majorcontributor to fine particles in urban sites. Besides these, mobile source and volatile source alsomade a contribution. Among the four major cities (Shanghai, Hangzhou, Nanjing, Hefei), the largestemission sources for fine particles were industrial emission source and fugitive dust, and the nextwere combustion source (including industrial boiler, furnace and electric plant), mobile source andvolatile source; industrial emission occupied quite a large proportion in Hangzhou local emissionsources, at the same time, fugitive dust and agricultural source also had a great contribution to fineparticle concentration; for Nanjing and Hefei, the largest three sources for local PM2.5were processengineering source, industrial boiler and furnace, and fugitive dust.In Yangtze River Delta, key components like sulfates and nitrates had a larger proportion inPM2.5. For components of fine particles, element carbon had a higher contribution in northernJiangsu area while organic carbon had a larger proportion in south central of Yangtze Delta. For thefive key components of fine particles in Shanghai, Hangzhou, Nanjing and Hefei, sulfates weremainly from process engineering source, industrial boiler and furnace, and electric plant emissions;nitrates were mainly from industrial furnace, electric plant and mobile sources; ammonia weremainly from agricultural and volatile source; process engineering source, mobile source and fugitivedust had great contributions to element carbon; and the sources of organic carbon were muchdispersive, all process engineering source, boilers, furnaces, volatile source and fugitive dust madea certain contribution. From the results of four different episodes, under adverse weather condition,the contributions of boilers, furnaces and electric plant sources to nitrates increased. During theclean period, which is local affected, process engineering source was a more significant contributorto these five key components.