Impact of anthropogenic emission on air quality over a megacity – revealed from an intensive atmospheric campaign during the Chinese Spring Festival

Abstract

The Chinese Spring Festival is one of the most important traditional festivals in China. The peak transport in the Spring Festival season (spring travel rush) provides a unique opportunity for investigating the impact of human activity on air quality in the Chinese megacities. Emission sources are varied and fluctuate greatly before, during and after the Festival. Increased vehicular emissions during the "spring travel rush" before the 2009 Festival resulted in high level pollutants of NO<sub>x</sub> (270 μg m<sup>−3</sup>), CO (2572 μg m<sup>−3</sup>), black carbon (BC) (8.5 μg m<sup>−3</sup>) and extremely low single scattering albedo of 0.76 in Shanghai, indicating strong, fresh combustion. Organics contributed most to PM<sub>2.5</sub>, followed by NO<sub>3</sub><sup>−</sup>, NH<sub>4</sub><sup>+</sup>, and SO<sub>4</sub><sup>2−</sup>. During the Chinese Lunar New Year's Eve and Day, widespread usage of fireworks caused heavy pollution of extremely high aerosol concentration, scattering coefficient, SO<sub>2</sub>, and NO<sub>x</sub>. Due to the "spring travel rush" after the festival, anthropogenic emissions gradually climbed and mirrored corresponding increases in the aerosol components and gaseous pollutants. Secondary inorganic aerosol (SO<sub>4</sub><sup>2−</sup>, NO<sub>3</sub><sup>−</sup>, and NH<sub>4</sub><sup>+</sup>) accounted for a dominant fraction of 74% in PM<sub>2.5</sub> due to an increase in human activity. There was a greater demand for energy as vast numbers of people using public transportation or driving their own vehicles returned home after the Festival. Factories and constructions sites were operating again. <br><br> The potential source contribution function (PSCF) analysis illustrated the possible source areas for air pollutants of Shanghai. The effects of regional and long-range transport were both revealed. Five major sources, i.e. natural sources, vehicular emissions, burning of fireworks, industrial and metallurgical emissions, and coal burning were identified using the principle component analysis. The average visibility during the whole study period was less than 6 km. It had been estimated that 50% of the total light extinction was due to the high water vapor in the atmosphere. This study demonstrates that organic aerosol was the largest contributor to aerosol extinction at 47%, followed by sulfate ammonium, nitrate ammonium, and EC at 22%, 14%, and 12%, respectively. Our results indicated the dominant role of traffic-related aerosol species (i.e. organic aerosol, nitrate and EC) on the formation of air pollution, and suggested the importance of controlling vehicle numbers and emissions in mega-cities of China as its population and economy continue to grow

Chemical Composition of PM2.5 and its Impact on Visibility in Guangzhou, Southern China

“…These values are comparable with previous studies conducted in the PRD, with values between 1.1 and 2.4 (Cao et al, 2003(Cao et al, , 2004(Cao et al, , 2007Huang et al, 2012). On the other hand, the annual average ratio of OC to EC was about 5.5 in Guangzhou, which is similar to or higher than the values at urban areas in the Southeastern USA and Europe (Lim and Turpin, 2002;Weber et al, 2007;Blanchard et al, 2011;Yubero et al, 2014).…”

Estimation of the direct and indirect impacts of fireworks on the physicochemical characteristics of atmospheric PM<sub>10</sub> and PM<sub>2.5</sub>

“…Celebrations during CNY season tend to spill over into the preceding and succeeding days (usually until the Lantern Festival, another important festival in China), along with sporadic fireworks. During the firework displays, the anthropogenic emission patterns are greatly changed (Huang et al, 2012). Many ordinary activities are decreased, such as certain industries and traffic (Feng et al, 2012), whereas degradation of the air quality may occur due to displays of fireworks.…”

Chemical Characteristics of PM2.5 during 2015 Spring Festival in Beijing, China

“…Meanwhile, fireworks burning becomes an important pollution source during the Spring Festival. There have been some studies on the characteristics of fireworks pollution, including its impacts on fine and coarse particles (Chang et al, 2011;Huang et al, 2012;Li et al, 2013;Jing et al, 2014;Zhao et al, 2014;Jiang et al, 2015;Lin et al, 2016), source apportionment (Feng et al, 2012;Tian et al, 2014b) and human health risk assessment Shi et al, 2014;Yang et al, 2014).…”

“…Burning fireworks releases huge amounts of gaseous pollutants, such as sulfur dioxide (SO 2 ) (Huang et al, 2012), nitrogen oxides (NO x ), carbon dioxide (CO 2 ), and carbon monoxide (CO) (Wang et al, 2007;Vecchi et al, 2008;Huang et al, 2012), as well as suspended particles containing water-soluble ions, organic/elemental carbon and trace metals (Drewnick et al, 2006;Sarkar et al, 2010;Jiang et al, 2015;Kong et al, 2015). It has been noted before that firework displays could lead to a sharp increase in PM 2.5 concentrations (Wang et al, 2007;Feng et al, 2012;Tsai et al, 2012;Han et al, 2014) and generates haze pollution within a short time (Sarkar et al, 2010;Tian et al, 2014b).…”