The Ratio Characteristics And Source Apportionment Of PM₁₀ And PM_2.5 In The City Of Kunming

The characteristics of mass concentration of PM10and PM2.5in domestic typical cities (Kunming, Changsha, Hangzhou, Shanghai, Harbin, Beijing, Wuhan, Guangzhou) have been analysed. The correlation between the meteorological factors (temperature, humidity, wind speed and visibility) and the characteristics has been discussed. The atmospheric concentrations characteristics, the preliminary source and the difference of PM10and PM2.5in Kunming were studied. The data of PM2.5and PM10were collected over four seasons from2013to2014in dongfeng east road Kunming. The water-soluble ions, polycyclic aromatic hydrocarbons, OC/EC and inorganic elements of the particulate matter were tested by ion chromatography, high performance liquid chromatography (HPLC), heat light carbon analyzer, inductively coupled plasma mass spectrometry ICP-MS) and inductively coupled plasma spectrometry (ICP-OES). The conclusion is as follows:(1)The characteristics of PM10and PM2.5are similar in each cities, the minimum in July, the maximum in December, this is consistent with the report by some articles, and it can indicate that the concentration of particulate matter has close relation with meteorological condition. The ratio of PM2.5/PM10beyond0.5most of the time, the PM10is mainly made up of PM2.5in each cities. The concentration of PM10and PM2.5have negative correlation with temperature, but the correlation of PM10and PM2.5with relative humidity and wind speed are not consistent in each cities, this is maby as the different area and different climate, and the correlation with visibility is also the negative.(2)The annual mean concentration of PM10and PM2.5are257μg/m3and123μg/m3respectively at the area of Kunming, and beyond the second standard by243%and251%respectively. The ratio of PM2.5/PM10range fom0.37to0.67, the mean is0.48, it indicate that PM2.5is the mainly composition of PM10. the pollution by PM2.5can not be ignored. The mass of water-soluble ions, inorganic elements, polycyclic aromatic hydrocarbons and OC/EC account for11.84%,22.69%,0.024%,11.10%in respectively, and10.07%,24.67%,0.019%,24.03%in PM2.5respectively. The concentration of Ca2+and SO42-are higher than other water-soluble ions, SOR reached33.22%.17.17%in PM10and PM2.5, it indicate that secondary pollution are exist in PM10and PM2.5, the ratio of NO3-/SO42-reached0.1and0.08in PM10and PM2.5respectively, it indicate that the fuel of coal has a big contribution to NO2and SO2in the air. The concentration of inorganic elements in PM10and PM2.5are58.3μg/m3、30.3μg/m3, account for22.69%and24.67%respectively, the concentrations of Ca, Si, Na, Al, K, Fe, Mg are higher, their mass all account for91.01%in inorganic elements of PM10and PM2.5. The concentration of polycyclic aromatic hydrocarbons in PM10and PM2.5are62.6ng/m3and23.1ng/m3, account for24.36%and18.80%respectively, the polycyclic aromatic hydrocarbons of larger molecular mass have higher concentration, and in general, the pollution is seriously in winter. The concentration of OC and EC are21.7μg/m3and6.6μg/m3in PM10,21.2μg/m3and6.3μg/m3in PM2.5, there are a good correlation between OC with EC in PM10and PM2.5, the R2reached0.82and0.92, it indicate that OC and EC have some common sources. The ratio of OC/EC reached3.26and3.37in PM10and PM2.5respectively, both of the ratio beyond2, it can indicate that secondary pollution has the contribution to OC in PM10and PM2.5.(3)The concentration of particulate matter has positive correlation with wind speed, weak positive correlation with temperature, strong negative correlation with relative humidity. The correlation with wind speed and relative humidity is consistent with the conclusion in the fourth chapter, but the different with temperature, this is maybe as the temperature is similar in spring and summer at the area of Kunming, the different of temperature can not be reflected. As the strong ultraviolet ray and low relative humidity, the concentration of particulate matter is higher in spring because of the higher wind speed, this is different from some other cities. (4) The PCA indicated that the main source of inorganic elements in PM10are chemical pollution (34.90%), building cement dust and soil dust (22.96%), source of made alloy (9.61%), source of iron and steel smelting (7.33%); The main source of inorganic elements in PM2.5are chemical pollution (45.14%), building cement dust and soil dust (11.32%).The PCA indicated that the main source of water soluble ion in PM10are biomass buring and soil dust(40.38%), vehicle exhaust and coal(32.91%); The main source of water soluble ion in PM2.5are biomass buring and soil dust(30.54%), vehicle exhaust and coal(25.13%), construction dust(25.13%).The PCA indicated that the main source of PAHs in PM10are vehicle exhaust(63.61%) and coal(19.85%); The main source of PAHs in PM2.5are coking(49.42%), coal(36.83%) and Biological (6.84%).