Changes in chemical components of aerosol particles in different haze regions in China from 2006 to 2013 and contribution of meteorological factors

Abstract

Abstract. Since individuals experienced persistent haze-fog events in January 2013 in central-eastern China, questions on factors causing differences in drastic changes in 2013 from those in adjacent years have been raised. Changes in major chemical components of aerosol particles over the years also remain unclear. The extent of meteorological factors contributed to such changes is yet to be determined. The study intends to present the changes in daily-based major water-soluble constituents, carbonaceous species and mineral aerosol in PM10 at 13 stations within different haze regions in China from 2006 to 2013, associated with specific meteorological conditions that are highly related with aerosol pollution (parameterized as an index called "PLAM"). No obvious changes were found in annual mean concentrations of these various chemical components and PM10 in 2013, relative to 2012. By contrast, wintertime mass of these components were quite different, in Hua Bei Plain (HBP), sulfate, OC, nitrate, ammonium, EC, and mineral dust concentrations in winter were approximately 43, 55, 28, 23, 21 and 130 μg m−3, respectively; these masses were approximately two to four times higher than those in background mass, also exhibiting a decline during 2006 to 2010, and then a rise till 2013. The mass of these concentrations and PM10, except mineral, respectively increased by approximately 28 to 117 and 25 % in January 2013 compared with that in January 2012. Thus, persistent haze-fog events occurred in January 2013, and approximately 60 % of this increase in component concentrations from 2012 to 2013 can be attributed to severe meteorological conditions in the winter of 2013. In Yangtzi River Delta (YRD) area, winter masses of these components, unlike HBP, did not significantly increase since 2010; PLAM was also maintained at a similar level without significant changes. In the Pearl River Delta (PRD) area, the regional background concentrations of the major chemical components were similar to those in YRD; accounted approximately 60–80 % of these in HBP. Since 2010, a decline was found for winter concentrations, which can be partially attributable to a persistent bettering meteorological conditions and the emission cutting with an emphasis on coal-combustion in this area. In addition to the scattered and centralized coal-combustion for heating, burning biomass fuel contributed to the large increase in the concentrations of carbonaceous aerosol in major haze regions, except in PRD, in winter. No obvious changes were found for the proportions of each chemical components of PM10 from 2006 to 2013. Among all of the emissions recorded in chemical compositions in 2013, coal-combustion was still the largest anthropogenic source of aerosol pollution in various areas in China, with higher sulphate proportion of PM10 in most areas of China. OC normally ranked the third. PM10 concentration increased by approximately 25 % in January of 2013 relative to 2012 that caused persistent haze-fog events in HBP; emission also reduced by approximately 35 % in Beijing and its vicinity (BIV) in late fall of 2014, thereby producing "APEC" blue; thus one can expect that the persistent haze-fog events would be reduced significantly in the BIV, if ~ one-third of the 2013 winter emission could be reduced, which can also be viewed as the upper limit of atmospheric aerosol pollution capacity in this area.