Atmospheric Gaseous Pollutants Dry Deposition And Ecological Effects In Agricultural Sites In Beijing-tianjin-hebei Region

Dry deposition is one of the main processes of pollutants removal from the atmosphere, settlingto the surface can affect the earth biochemical circulation and do harm to human health.Beijing-Tianjin-Hebei region is our country’s political, economic and cultural center, In recently, ithas been present high particles and high ozone concentrations conditions of atmospheric compoundpollution characteristics due to the burning of fossil fuels, the use of nitrogen fertilizer and theinfluence of human activities, such as animal husbandry, large numbers of volatile inorganic andorganic compounds, photochemical oxidants and fine particles. Regional compound pollutants areeasy to accumulate, especially in the stable weather condition, and the visibility continutes todecline, causing heavy regional air pollutions. This paper talks about regional gas pollutants drydeposition concentration characteristcs, change principles and ecology effects, which will have animportant guide significance on the environment and climate as well as providing some scientificreference and technology support.In order to investigate the pollution levels and change principles, the concentrations of SO₂, NO₂,O₃,NH₃and BTEX were parallel measured by Italy Analyst individual passive samplers andanalyzed using GC-MS and ICS-90during2008-2010in Beijing-Tianjin-Hebei region. The drydeposition fluxes of SO₂, NO₂, NH₃and the total inorganic nitrogen were also calculated inagro-ecological stations Luancheng and Yucheng, and finally the paper preliminary discussed theecology effects. The paper obtained the following results:（1） The concentrations of SO₂showed a declining trend during2008-2010, while NO₂showed aascending trend, while O₃showed a ascending trend in Yucheng, the concentrations of O₃firstlydeclined and then ascended in Luancheng, and NH₃had no obvious interannual variabilities inLuancheng and Yucheng. The annual average concentrations of SO₂exceeded the world healthorganization standard (30μK·Q^-3)in Luancheng and Yucheng. The highest concentrations of O₃happened in Xinglong site, NH₃for Yucheng, Luancheng and Tanggu sites. The seasonalcharacteristics of SO₂and NO₂showed“U”type with high in double heads and low in middle,high in winter, low in summer, and the spring and antumn periods were middle. Theconcentrations of SO₂in Luancheng and Yucheng in winter were （138.3±21.2） and （82.1±17.6） μK·Q^-3, respectively, while SO₂in summer were （42.8±5.4） and （31.9±6.1） μK·Q^-3, respectively. The concentrations of NO₂in Luancheng and Yucheng in winter were （67.2±15.1）and （54.0±8.8） μK·Q^-3, respectively, while NO₂in summer were （24.0±3.4） and （17.9±0.1）μK·Q^-3, respectively. O₃was high in summer, low in winter, and the spring and autumn periodswere middle. The highest concentrations for O₃in summer was in Xinglong, with values of（132.2±17.8） μK·Q^-3, while the lowest concentrations was in Luancheng, with values of （12.8±0.3） μK·Q^-3. NH₃was high in summer, low in winter. The highest concentrations for NH₃insummer was in Luancheng and Yucheng, with values of （36.1±16.3） μK·Q^-3and （28.9±11.4）μK·Q^-3, while the lowest concentrations was in Xinglong.The highest concentrations for NH₃inwinter was in Tanggu, with values of （21.6±9.7） μK·Q^-3, while Xinglong had the lowest NH₃concentrations, with values of （1.6±0.9） μK·Q^-3.（2） The concentrations of BTEX in agricultural sites were lower than that in city sites during2008-2010in Beijing-Tianjin-Hebei regin. The concentrations of BETX in Luancheng andYucheng were26.1and14.7μK·Q^-3. The concentrations of BETX in Tanggu was the highest,with values of77.2μK·Q^-3, followed by Beijing, Tianjin, Tangshan, Baoding and Luancheng,with values of23.4μK·Q^-3,26.9μK·Q^-3,26.1μK·Q^-3,23μK·Q^-3and26.1μK·Q^-3, respectively,Xinglong had the lowest BTEX concentrations, with values of11.0μK·Q^-3, and it’s the only sitethat the concentrations of benzene didn’t exceed the average emission standard of EuropeanUnion (5μK·Q^-3). The most aboundant compound in Beijing and Tianjin was toluene, followedby benzene, ethylbenzene and m/p-xylene, and the most aboundant compound in Baoding,Tangshan, Yangfang, Cangzhou, Luancheng, Yucheng, Tanggu and Xinglong was benzene,followed by toluene, ethylbenzene and m/p-xylene.（3） The seasonal characteristics of BTEX in Xinglong were high in summer, low in winter, and thespring and autumn periods were middle, while Yangfang were high in autumn, low in spring,and the summer and winter periods were middle, and the other sites were high in winter,followed by autumn, summer and spring. The ratios of B/T>1in winter, B/T<1in spring,summer and autumn in Beijing and Tianjin, which indicated that coal heating may be the mainsource of BTEX in winter, and the automobile emissions may be the main source in spring,summer and autumn. The ratios of B/T≥1in four seasons in Baoding and Tangshan, whichindicated that coal heating may be the main source of BTEX. The ratios of B/T<1in spring andautumn, B/T>1in summer and winter in Yangfang, which indicated the automobile emssions may be the main source in spring and autumn, and the biomass in summer, the coal heating inwinter may contribute more to BTEX. The ratios of B/T>1in four seasons in Cangzhou,Luancheng, Yucheng and Xinglong, the biomass and the coal heating and the other sources maycontribute more to BTEX. The correlations between BTEX were better in winter than that insummer in agricultural sites, the city sites were the exact opposite, which indicated the source ofBTEX in winter was single in agricultural site, and the source was single in summer in citysites.The correlation coefficient between benzene and m/p-xylene in winter in agricultural siteswas0.91, the correlation coefficient between ethybenzene and m/p-xylene was0.90, whichindicated that the benzene, ethylbenzene and m/p-xylene may come from the same source. Thecorrelation coefficient between ethylbenzene and toluene was0.82, they may come from thesame source.（4） The dry deposition rates were in dynamic changes during2008-2010in Yucheng andLuancheng. In general, they were high in summer and autumn, and low in winter and spring.The same species in different areas had slightly different dry deposition rates. The month drydeposition rates ranges for NH₃, NO₂and SO₂in Yucheng were3.8¹2.80.2¹.7and1.1⁸.8mm·s^-1. Respectively. In Luancheng they were3.0¹2.4,0.2¹.1and1.2⁹.2mm·s^-1.Respectively. The different species in the same area had different dry deposition rates, the lagestdry deposition was NH₃, followed by SO₂and NO₂. The NO₂showed no obvious interannualdifference, while NH₃and SO₂showed double peaks.（5） The dry deposition month fluxes ranges for NH₃, NO₂and SO₂were0.9¹4.5,0.2⁰.9and1.1¹2.8Kg·ha^-1·month^-1, respectively. In Luancheng, they were1.1¹3.2,0.2¹.4and1.2²6.9Kg·ha^-1·month^-1, respectively. The interannual dry deposition fluxes for NH₃showedfirst declining and then ascending trend, and NO₂showed ascending trend, while SO₂showeddeclining trend. The dry deposition fluxes for NH₃during2008-2010in Yucheng were42.9,40.3and49.7Kg·ha^-1·a^-1, respectively, with average values of44.3Kg·ha^-1·a^-1, and for NO₂theywere4.5,5.1and5.5Kg·ha^-1·a^-1，respectively, with average values of5.1Kg·ha^-1·a^-1, and forSO₂they were67.7,50.1,40.6Kg·ha^-1·a^-1, respectively, with average values of52.8Kg·ha^-1·a^-1.While the dry deposition fluxes for NH₃during2008-2010in Luancheng were51.2,50.8and52.9Kg·ha^-1·a^-1, respectively, with average values of51.7Kg·ha^-1·a^-1, and for NO₂they were4.8,5.7and6.3Kg·ha^-1·a^-1, respectively, with average values of5.6Kg·ha^-1·a^-1, and for SO₂they were105.4,75.9and50.5Kg·ha^-1·a^-1，respectively, with average values of77.2Kg·ha^-1·a^-1.Theratios of NH₃/SO₂<1, which indicated agricultural sites were priority to acid precipitation.Thetotal inorganic nitrogen dry deposition fluxes was about52.2¹65.7KgN·ha^-1·a^-1in Yucheng,and it was60.7¹92.6KgN·ha^-1·a^-1,in Luancheng, which were more than the critical load ofnitrogen deposition of15³0KgN·ha^-1·a^-1.