Invisible Cities
The sources of air pollutants and mitigating solutions
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- 2.5.2 Mitigation of air pollution
2.5 The sources of air pollutants and mitigating solutions2.5.1 Retrieving the sourcesSince PM 2.5 is a critical air pollutant and also an indicator of air quality, it is logical to track the sources of pollution through its composition. Bergin et al (2001) studied the data over 7 days of mid- June 1999 in Beijing, observed the main chemical components of PM 2.5, which are organic compounds, sulfate and nitrate. Ye et al (2003) operated a one-year experiment in Shanghai from March 1999 to March 2000, manifested the similar results about the compositions. Buczynska et al (2014) also overviewed the composition of PM 2.5, and added crustal matter, sea salt, smoke and other elements (including heavy metals) into the analysis as well. Based on these components, several sources that related to PM 2.5 can be reasonably traced. Both natural and anthropogenic reasons play a role, and they also influence each other mutually. The natural factors increase and dilute PM 2.5 in both ways, while the anthropogenic factors contribute to the emission. The natural factors are related to terrain of the focused place, and the most important three factors are temperature, humidity and atmospheric movements (wind). Many studies found that there is a strong seasonal variation of PM 2.5 concentration that takes place in the late autumn and early winter. Thus, to some extent, lower temperature increases the emission of PM 2.5, and the heating started due to the cold weather is the most accepted causation (Ye et al., 2003; Buczynska, et al., 2014). The sample of air frog collected in Shanghai showed that sulfate and nitrite compounds are significantly lower in the locations close to the sea because of the higher humidity. Furthermore, the content of sea salt increases with the proximity of the sea, which facilitates the generation of PM 2.5 (Li, Li, Yang, Wang, Chen, & Collett Jr., 2011). Finally, all the above-mentioned researches conducted a back trajectory analysis, concluded that strong wind can bring in and out particles. The wind force also matters, weak wind force usually causes poor air quality for Chinese cities, since it cannot blow the pollutants in time – Beijing, located in a U-shape terrain, is a distinguish example for this case (Chen, Schleicher, Chen, Chai, & Norra, 2014).
Figure 4: Compositions of PM 2.5 in Los Angeles 
Source: (U.S Environmental Protection Agency, 2004) Subsequently, which is a unique characteristic in China, another equally important reason is rapid urbanization and industrialization since 1978. It is mentioned in almost all the articles for this topic in China (e.g. Ye et al., 2003; Kleeman & Cass, 1998). Indeed, in order to achieve the economic reform, mass scale of infrastructure construction was triggered in every city, and inevitably sacrificed some natural resources. Other type of chemical pollutants, for example, calcium ion solubilized in the fog water, was mainly generated from construction. The smelting plants of iron and steel, or other metal are responsible as well, evidenced by ions of heavy metals in captured samples. The observation in Foshan (a city in Guangdong Province, south China) discovered the high concentration of Zn, Pb, V, Mn, Cu, As and Cd in their sample of air particles (Tan et al., 2014). In addition, the metal ions are also manifested that could result from the intensive agricultural emission from proximate regions. 2.5.2 Mitigation of air pollutionFirst it should be noticed that air is a pure public good by its attribute, implying that market will produce inefficient results if only private benefit/cost is concerned (Olson & Olson, 2009). The solution to such a problem, the most common method is calling for the government intervention, in order to take social benefit/cost into account, by setting up relevant regulations, or imposing taxation (La Porta, Lopez-de-Silanes, Shleifer, & Vishny, 1999). Therefore, the frequent occurrences of haze weather, to some extent, reflected the failure of institutional mechanism and lack of administrative forces in China. But it is still a task to complete for the government. Winning the bid of Olympic Games in 2008, gave Beijing a great platform to show the great achievements of modernization in the past half century, but more importantly, urged government to solve air pollution problem in order to prove the sustainability of its development. Thus, such a mega event, and the event tourism generated by it, is calling for the Chinese government to pay attention to it. As a result, the government implemented a series of strategies to ensure a better air quality during the Summer Olympic Games in 2008. Due to the intervention, a significant reduction of mass concentration of air pollutants was achieved in Beijing at that time. Mega event is a tool used by the government to solve air pollution, because it is reasonable to implement special policies or carry out certain projects to mitigate pollution in order to improve perception of destination image for event tourism. Looking it into the details of Beijing Olympics, there are two main methods they adopted to improve air quality. The primary is traffic restriction, including improving emission standards, odd-even restriction of private car license, and 1/5 reduction of weekly passenger car flow. With a 32.3% decrease of traffic flow, almost a half of reduction of concentration for traffic-related elements were collected in the sample of Olympic time period, comparing with the sample of December 2007 (Wang & Xie, 2009). Another is implementing the project of relocating the Capital Steel Company, moving from Beijing to Hebei gradually. As a result, the concentration of heavy metal ions in the air sample also had a significant drop (Chen, Schleicher, Chen, Chai, & Norra, 2014). Overall, through these efforts contributed to mitigate contamination, the air quality during the Olympics met the WHO guideline. Nevertheless, as pointed out before, the recent published researches presented of a large scale of severe haze weather in 2013, unmasked a failure of sustainability of the intervention of Beijing in rooting out the sources air pollutants. It is not surprising that the move of Capital Steel Company worsened the situation in Hebei Province, which became the most polluted region in the eastern China. Therefore, in order to really mitigate the contamination up in the air, government in Chinese cities need to come out with more effective and sustainable solutions. Akbari, Pomerantz, & Taha (2001) discussed some methods for reducing the concentration of air pollutants. They suggested that cool surfaces (cool roofs and pavements) and urban trees will significantly reduced the smog generated by energy consuming, in other words, inceneration activities. It was manifested in Chicago, that green roofs largely removed the air pollutants (Yang, Yu, & Gong, 2008), and also many other cities in the U.S. that urban trees considerably improved air quality (Nowak, Crane, & Stevens, 2006). Directory: pub pub -> Project Scoring Template Pre-Construction Phase New Core/Branch Campus Projects pub -> Acm word Template for sig site pub -> The german unification, 1815-1870 pub -> Baltic Olympiads in Informatics: Challenges for Training Together pub -> Preparation of Papers for ieee transactions on medical imaging pub -> Forthcoming meetings and conferences pub -> Asilomar Conference on Circuits, Systems & Computers, Pacific Grove, ca, November 1978, pp. 55 58 pub -> Forthcoming meetings and conferences pub -> Harmonised compatibility and sharing conditions for video pmse in the 7 9 ghz frequency band, taking into account radar use Download 352.16 Kb. Share with your friends:
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