The Analysis Of The Pollution Characteristics And Influence Factors Of PM₂.5 In Beijing During The Olympic Games

In order to guarantee the best air quality during 2008 Olympic Games effectively, Beijing have developed and implemented a number of stringent ambient air quality protection measures, Hebei, Shandong, Shanxi, Tianjin, the Inner Mongolia also adopt the zone defense association to control the measure. Key aimed at the electric power, the cement, the building materials etc, main pollution profession to eliminate backward production capacity and technology. And we carry on the real-time monitoring to the large-scale thermoelectric power station.Based on the analysis of Particulate Matter 2.5 mass concentration, gaseous pollution, meteorological data during the same period of the year before and after the Olympic Games, time, etc., Analysis PM_2.5 air pollution in Beijing and the correlation between its affecting factors(meteorological factors) ,a typical process is studied. This thesis conducted a detailed analysis of test data as follows:â‘ The PM_2.5 mass concentration: of the 7 stages around the Olympic Games, the Olympic Games stage's ambient air quality is best as a whole, the PM_2.5 mass concentration is lowest; On the same time of Olympic Games period between 2007 and 2009, the quality in 2008 is more superior, the concentration of pollutants rebounded to some extent in 2009 .During the Olympic Games, the PM_2.5 mass concentration changed tendency obviously gentler than same time of 2007, besides on August 8 10, other time intervals the density maintain at the relatively low level; The highest three kind of water-soluble inorganic ions in PM_2.5 are SO₄^2-, NO₃^- and NH₄⁺.â‘¡mass concentration and meteorological related factors of PM_2.5: the paper discussed the relevance between inorganic ions of PM_2.5 and the gaseous pollutant. The result shows: tendency between SO₄^2- and SO₂ are great, so as NO₃^- and NO₂. The SOR value and the NOR value are bigger than 0.1, indicated that SO₂ and NO₂ transformed to secondary aerosol in large. The research indicated that PM_2.5 and the visibility show great negative exponent relevance; And when RH is 70%⁸0%, the relevance to be best; When the PM_2.5 mass concentration is less than 0.05mg/m³ ,the visibility descend sharply. The precipitation has a remarkable scavenging action to the particles, the accumulation precipitation and PM_2.5 presents a great inverse correlation relations. Simultaneously also gets a chill and so on other meteorological factor the influence. Generally when the wind speed is smaller than 2m/s, the relevance between PM_2.5 and wind speed is not very obvious; But when the wind speed surpasses 2m/s, high wind speed is often correspond to the relatively low particles density. The southerly flows of wind easily lead to transport of fine particles to the accumulation of Beijing. Through the Hysplit air current backward trajectory model analysis pollutant's origin, indicated finally the air pollutant mainly comes from Hebei and Shandong area.â‘¢A typical produce and eliminate process of PM_2.5 during early 2008 Olympic Games in Beijing Area: based on the analysis of PM_2.5 mass concentration, meteorological data during the corresponding period etc, combined with the different analytical methods on meteorological flow fields, a typical process is studied. The results indicated that: during the ascent stage of PM_2.5 concentration ,the PM showed gradually aged; the process controlled by large scale synoptic system mainly ,and the weak wind , the high humidity which were not in favor of dispersion ; the prolonged southerly air mass to bring the pollutant of Hebei and Shandong to Beijing ; mixing height and temperature curve take the importance role to the concentration .When the inversion layer appears , the atmosphere is stable and does not favor of diffuse.