Study On Improved Source Apportionment Technique Of PM₁₀ In ChongQing

Inhalable particulate matter is an important index for atmospheric environmental quality and the major pollutants which impact the urban air quality;also is harm for human health.So conducting the source apportiomnent of PM₁₀,namely identifying the sources of PM₁₀ and calculating the contribution rate of PM₁₀,atmospheric particulate matter will be more targeted treatment and it is of great significance for the development of practical air pollution control measures and the improvement of air quality of the urban environment.The source apportionment of PM₁₀ was conducted in Chongqing for providing scientific basis and technical support for the preventing work of air pollution in Chongqing.In this paper,factor analysis(FA) model was used to identify the sources of PM₁₀,improved source apportionment technique was used to analyze.All is used for source apportionment to provide some references for the technical methods.The main conclusions are as follows:(1) The concentration of PM₁₀ in Chongqing main city during the sampling in spring and autumn is 0.154 mg/m³ and 0.230mg/m³ respectively.The mass concentrations were characteristic of seasonal and regional variety.The concentration of PM₁₀ every sampling site in autumn was higher than in spring.The highest concentration of PM₁₀ in Shapingba district,the value is 0.267 mg/m³,the lowest concentration of PM₁₀ in Jinyunshan district,the value is 0.092 mg/m³.The order of concentration from high to low is Shapingba,Dadukou,Yuzhong,Yubei,Nanan, Jiangbei and Jinyunshan.The order of concentrations from high to low was:Integrated Industrial Parks,Sowntowns,Residential Areas and Tourist Districts.(2) The mass concentrations of inorganic elements component in PM₁₀ were characteristic of seasonal and regional variety.The component concentrations of PM₁₀ in autumn are higher than spring,especially the increase of Si,S and Ca in inorganic elements.The change of concentration of Fe and K by the impact of seasonal variations is smaller.In the developed areas that have lots of industries,commerces,population and traffics,the mass concentrations of inorganic elements component in PM₁₀ were generally higher than in other areas.(3) The organic carbon mass concentrations of PM₁₀ was increase 73.2%in the autumn compared to spring,the relative changes of EC in weather conditions smaller than OC;In the developed areas that have lots of industries,commerces,population and traffics,the OC and EC component concentrations of PM₁₀ were generally higher than in other areas.The average concentration of OC in the carbon components of tow season account for 80%,while the EC 20%.The average concentration of OC/EC in the carbon components of two season reach to 4.46 and the autumn OC/EC ratio is higher than the spring;Study of the pertinency suggests the sources of OC and EC is more in line,them may be the vehicle exhaust emissions and coal-fired.(4)the concentration of water-soluble ions in the autumn have the general increase compared with spring,including NO₃^-,SO₄^2-and NH₄⁺ have a more pronounced increase, respectively,increased by 34.66%,57.82%and 79.01%;The concentration of SO₄^2- in all components is the highest levels of receptor components,the average concentration of two season reach to 28.27μg/m³.NO₃^-/SO₄^2- of Main City in two seasons has a average value of 0.28,the main source of pollution of Chongqing main city is still a fixed-source,mainly from coal-fired emissions,but the impact of mobile sources also gradually increased.(5) Secondary particles,fugitive dust,cement dust,steel dust and traffic dust the five pollution factors of PM₁₀ in Chongqing were identified by FA mode.At last the main pollution sources of PM₁₀ in Chongqing were identified as fugitive dust(including soil dust and road dust),cement dust,coal smoke dust,mobile exhaust gas dust,steel dust and secondary particles(including secondary sulfate,secondary nitrate and secondary organic carbon) to perfect the pollution sources classification system of PM₁₀.(6) The source of PM₁₀ in Chongqing main city was analyzed by improved source apportionment technique in the paper.The result showed that The mostly source of PM₁₀ in Chongqing city is s dust,mobile exhaust gas,econdary particle,cement dust, steel dust,coal smoke dust,and the contribution is 32.71%,20.14%,17.31%,9.23%, 3.98%,5.40%.