Estimation of the Main Factors Influencing Haze, Based on a Long-term Monitoring Campaign in Hangzhou, China

East China is among the fastest developing area in Asia, where atmospheric aerosol loading is high due to heavy urban and industrial emission. The Moderate Resolution Imaging Spectroradiometer (MODIS) level 2 aerosol products (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007) were used to study aerosol spatial and temporal distributions, as well as their variations with local meteorological conditions over East China. By combining Aerosol Optical Depth (AOD) and aerosol Fine Mode Fraction (FMF), we found that the urban/industrial aerosol and soil dust are possibly two dominant species over northern part, whereas continental and marine aerosols possibly dominate the southern part of East China. Both annual mean AOD and area with high AOD increased from 2000 to 2007, with the largest increase seen in Yangtze River Delta region (YRD). In summer, AOD in East China reached the maximum of about 0.8 in YRD, dominated by fine mode particles. The minimum AOD occurred in winter with mostly coarse mode particles. Local aerosol properties were analyzed in three typical zones: the northern dry zone (I), the central urban/industrial zone (II) and the southern natural background zone (III). Monthly mean AODs in zone I and II were above 0.5 throughout the entire year, with the maximum AOD in June. High FMFs in this period indicated heavy urban and industrial pollution. Monthly mean AODs and FMFs in zone III reached maximum of 0.51 in April and September (up to 90.7%) respectively. High AOD in spring in zone III appears mostly due to the long-range dust transport from the North.

Section: Introductionmentioning

confidence: 99%

Study on Long-term Aerosol Distribution over the Land of East China Using MODIS Data

Geng

et al. 2012

“…In recent years, the air pollution problem in Guangzhou has been of concern due to the adverse effects it may result in. Air pollution can decrease atmospheric visibility, change meteorological conditions, and negatively impact human health (Sun et al, 2006;Chan and Yao, 2008;Tie and Cao, 2009;Xiao et al, 2011;Lin et al, 2012). Particularly, the atmospheric visibility in Guangzhou has been significantly reduced with a reported decline rate of 0.3 km per year during the past four decades (Huang et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Application of Trajectory Clustering and Source Apportionment Methods for Investigating Trans-Boundary Atmospheric PM10 Pollution

Cheng

Wang

et al. 2013

A modeling framework was proposed to investigate the impact of trans-boundary air pollutant transport on regional air quality. This was based on a combination of the HYSPLIT trajectory model, the CAMx air quality model, and the MM5 meteorological model. The examination of atmospheric PM 10 pollution in Guangzhou within the Pearl River Delta (PRD) region of southern China was used as a case study. The HYSPLIT and MM5 models were used to qualitatively identify the dominant PM 10 pollutant transport pathways that led to PM 10 pollution events in Guangzhou, with five clusters of air mass trajectories being examined. The emission source contribution through each transport pathway to Guangzhou's PM 10 concentration was then quantified using a MM5-CAMx modeling system. The results illustrated that the trans-boundary PM 10 transport played a critical role in the formation of PM 10 pollution events in Guangzhou, with a mean contribution ratio of nearly 49%. In particular, two air mass trajectory clusters that originated from Guangzhou's surrounding regions were found to be the main pollutant transport pathways, and three surrounding cities (Foshan, Dongguan and Huizhou) had a total emission contribution of nearly 30% to Guangzhou's PM 10 concentration through these two pathways. The emissions from these three cities also accounted for 70 to 94% of the total trans-boundary contributions from Guangzhou's nine surrounding cities through the five transport pathways. As a result, in order to improve Guangzhou's air quality, coordinated effort is required to reduce emissions in both Guangzhou itself and its three surrounding cities. It is expected that the presented modeling approach can be applied to air quality studies in many other regions.

“…The seasonal variations of (NH 4 ) 2 SO 4 and crustal material associated with the long-range transport could be explained by the variation of source strength and the transition of the monsoon pattern. However, EC was spatially inhomogeneous and the ambient carbonaceous material was highly dominated by local mobile source emissions (Kim et al, 2011;Xiao et al, 2011;Zhang et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

The Characteristics of PM2.5 and Its Chemical Compositions between Different Prevailing Wind Patterns in Guangzhou

Chang

Chou

Liu

et al. 2013

An intensive campaign for atmospheric pollution was carried out from October to November 2004 in Pearl River Delta Region (PRDR) of China in order to better understand the dominative factors for controlling air quality and impacts of pollutants on the regional environment. The object of this study aimed to investigate the characters and sources of particulates through the study of chemical compositions in different wind pattern in Guangzhou city. The ambient concentrations of mass, soluble species, and carbonaceous matter in PM 2.5 particulates with time resolutions of 15 minutes, 15 minutes, and 12 hours were measured by TEOM, in-situ IC system, and carbon analyzer, respectively. During the sampling time, high concentrations of PM 2.5 mass and its chemical compositions were found, which was comparable or higher than other measurements in mainland China. The average SO 4 2-, NH 4 + , and NO 3 -concentrations were 38.6, 13.6, and 8.8 μg/m 3 , which accounted for 26.5%, 13.6%, and 5.7% of the total particulate mass, respectively. In the frontal system, biomass burning was the significant emission source and the great amount of SO 4 2-and NH 4 + particulates were observed in the aged secondary particulates, together with the dry prevailing northerly wind. In the local system, low value of sulfur oxidation ratio and high correlation coefficient between sulfate and elemental carbon were also observed under the prevailing southeasterly wind. It could be explained that the heterogeneous reaction of sulfate on soot particles causes high levels of NO x in Guangzhou. Great amount of SO 2 would further convert to secondary sulfate particles through photochemical reactions during transport to the inner areas, which will cause more serious air pollutions in the southern China.