Winter and Summer PM_2.5 Chemical Compositions in Fourteen Chinese Cities

Abstract

PM 2.5 in 14 of China's large cities achieves high concentrations in both winter and summer with averages >100 g m À3 being common occurrences. A grand average of 115 g m À3 was found for all cities, with a minimum of 27 g m À3 measured at Qingdao during summer and a maximum of 356 g m À3 at Xi'an during winter. Both primary and secondary PM 2.5 are important contributors at all of the cities and during both winter and summer. While ammonium sulfate is a large contributor during both seasons, ammonium nitrate contributions are much larger during winter. Lead levels are still high in several cities, reaching an average of 1.68 g m À3 in Xi'an. High correlations of lead with arsenic and sulfate concentrations indicate that much of it derives from coal combustion, rather than leaded fuels, which were phased out by calendar year 2000. Although limited fugitive dust markers were available, scaling of iron by its ratios in source profiles shows $20% of PM 2.5 deriving from fugitive dust in most of the cities. Multipollutant control strategies will be needed that address incomplete combustion of coal and biomass, engine exhaust, and fugitive dust, as well as sulfur dioxide, oxides of nitrogen, and ammonia gaseous precursors for ammonium sulfate and ammonium nitrate.Implications: PM 2.5 mass and chemical composition show large contributions from carbon, sulfate, nitrate, ammonium, and fugitive dust during winter and summer and across fourteen large cities. Multipollutant control strategies will be needed that address both primary PM 2.5 emissions and gaseous precursors to attain China's recently adopted PM 2.5 national air quality standards.

Identification and quantification of shipping emissions in Bohai Rim, China

“…Unlikely, Cao et al (2012) found high level of PM 2.5 in winter compared to summer in other regions in China. This is because the Northwest wind is the prevailing wind in spring and winter with a larger wind-speed in Bohai Sea.…”

Long-term trends of chemical characteristics and sources of fine particle in Foshan City, Pearl River Delta: 2008–2014

“…On average, the most abundant water soluble species in PM 2.5 were ranked as follows: The concentration of ss-sulfate (sea salt sulfate) comprised b 5% of the total sulfate measured, suggesting that sulfate is mainly derived from anthropogenic activities and secondary formation. The average concentrations of SO 4 2− in Foshan are comparable with those in Chongqing city, and higher than representative megacities such as Beijing, Guangzhou and Shanghai (Yang et al, 2011b); and lower than the coal-smoke-polluted cities in Western China such as Xi'an (Cao et al, 2012 There is an increasing trend of nitrate/sulfate ratio, suggesting that the contribution of mobile emissions in Foshan is significantly increasing. However, in general the ratio was b1, implying that coal combustion is still a primary source.…”

“…Beijing (Yang et al, 2011b) Chongqing (Yang et al, 2011b) Shanghai (Yang et al, 2011b) Guangzhou (Yang et al, 2011b) Chengdu (Tao et al, 2013) Xi'an (Cao et al, 2012) is an important manufacturing base in China, with coal as the primary energy source (Shen and Wei, 2012), and the production of ceramics in Foshan city contributes about 30% to total world production. Therefore, the restriction of coal combustion and the relocation of the ceramic industry from 2007 to 2010 dramatically reduced the emissions of elements from anthropogenic sources.…”

Chemical Composition of PM2.5 Based on Two-Year Measurements at an Urban Site in Beijing

“…On the other hand, higher concentration of nitrate would relate with the artifact of HNO 3 from the evaporation of nitrate ammonium under the high temperature. Many earlier studies have also observed higher inorganic species concentrations in summer at Xi'an and Beijing (Duan et al, 2006;Cao et al, 2012;Hu et al, 2014). The high loadings of OC, EC and chloride in winter are likely related with vehicles, combustion emissions and the low temperature.…”

“…A number of studies have dedicated to the characterization of particulate matter in recent years based on filters measurement and analysis in Beijing (He et al, 2001;Dan et al, 2004;Sun et al, 2004;Wang et al, 2005;Duan et al, 2006;Wu and Wang, 2007;Zhang et al, 2007;Pathak et al, 2009;Cao et al, 2012;Wang et al, 2013;Hu et al, 2014). These studies reported a lot of valuable results on PM and chemical composition in different years which make us understand aerosols properties better, but most of them focus on the characterization of aerosol at short-term measurements representing one or two seasons.…”