| With the rapid development of urbanization and industrialization, the urban environment has been polluted to different degrees, and the poor quality of air has become an important challenge for the healthy survival and sustainable development of urban residents. Main area of Lanzhou city, as the main place of energy, mass, momentum and water vapor exchange between human activities and atmospheric environment. The spatial and temporal distribution of atmospheric particulate matter and its components have important influence on the ecological environment and the health of the population in the main city of Lanzhou city. Therefore, it is very important to improve and expand the research on the characteristics of atmospheric particulate matter pollution, component and health indicators in the main city of Lanzhou city.In this paper, the characteristics of atmospheric particulate pollution and health risk in the main urban area of Lanzhou were studied. Atmospheric particulate matter mainly includes PM10、PM2.5 and eight particles(PM10.0-9.0、PM9.0-5.8、PM5.8-4.7、PM4.7-3.3、PM3.3-2.1、PM2.1-1.1、PM1.1-0.65、PM0.65-0.43). The spatial and temporal distribution characteristics of atmospheric particulate matter and the influence of the meteorological factors were studied by statistical analysis and correlation analysis of ArcGIS, and the heavy metal elements and water soluble ions in atmospheric particulate fractions were analyzed. Simulation of human respiratory system were sampled by Andersen eight level sampler, different particle size corresponds to the different human respiratory organs. The accumulation and heavy metal deposition of different size particles in the human respiratory organs were analyzed. And the heavy metal elements are classified into two types of carcinogenic and non carcinogenic elements, the health risks of different age and gender groups have been evaluated. The main results are as follows:（1）From 2000 to 2015, the average mass concentration of PM10 and PM2.5 showed a gradually decreasing trend in the main city of Lanzhou city. The seasonal average mass concentration of PM10 showed the highest in spring, the second in winter, and slightly higher than that in summer and the lowest in summer. Seasonal average PM2.5 mass concentration from the original with the regular seasonal variation of PM10 consistent, to the highest in winter, spring times, in summer and autumn season, the lower evolution. The spatial distribution pattern of PM10 and PM2.5 showed a patchy, zonal and patchy distribution pattern, and had a trend of high middle and low end. PM10、 PM2.5 and relative humidity are related to atmospheric visibility. The concentration of PM10 is higher than 0.2 mg/m3, the change of atmospheric visibility on the particle concentration is not obvious, is very sensitive in less than 0.2 mg/m3; When the PM2.5 concentration is higher than 0.12 mg/m3, the change of atmospheric visibility on the particle concentration is not obvious, very obvious in less than 0.12 mg/m3. The effect of wind speed and relative humidity on the quality of PM2.5 and PM10 was obvious. There is no significant correlation between temperature and atmospheric pressure with PM10 and PM2.5 mass concentration, which is not the direct factor of PM10 and PM2.5 pollution in the main city of Lanzhou.（2）This paper analyzes the main city in Lanzhou on the 14 kinds of heavy metals PM10, PM2.5 and eight grade particles. The Be, Cr, Mo, Ba and Tl were not detected, the detected elements are B, V, Mn, Fe, Co, Cd, Sb, Cu, Pb. Among them, B as a male reproductive health elements detected in higher concentrations, in particular by the sampling effect of membrane system error or particulate matter in the bottom value of high impact or affected by industrial pollution, need further study. The Pb and Cd elements in PM10, PM2.5 in the urban area of Lanzhou City 4 monitoring points in each season basically showed a strong enrichment, and as the season changes, the enrichment degree is not the same. Pb and Cd are the main contribution factor of potential ecological risk index in PM2.5 and PM10. The potential ecological risk coefficient of Cd in PM10 is 154.639-525.773, and the potential ecological risk of single factor is serious; The total potential ecological risk index was 243.407-648.625, and the total potential ecological risk degree was moderate and severe. PM2.5 particles in the total potential risk index is in the range of 199.377-804.703, the potential ecological risk degree is moderate- severe. In PM10 and PM2.5, water soluble ion PO43- was not detected. In spring, PM2.5 and PM10, the water soluble ionic composition of the two sampling points in the Lanlian hotel and the Zhigong hospital is the most similar. In PM2.5 and PM10, NO3-、Cl- and SO42- are homologous compounds, and the three sources may be the same; The correlation coefficient of Ca2+ and Mg2+ were 0.731, 0.766. The source may be the same, mainly from soil particles, dust, dust and other pollution sources. In PM2.5 and PM10, NO3-/SO42- value is 0.73, less than 1. Stationary source emissions is still the main source of pollution in Lanzhou city.（3） In the spring and winter, less than or equal to10μm of the mass concentration of particulate matter not with the decrease of particle size aerosol mass concentration decreases, but showing the two peak of the situation. The results of Lorenz curve analysis showed that PM2.1—1.1 diameter particles in the main urban area of Lanzhou in spring was more uniform, PM10.0—9.0 and PM9.0—5.8 particle size particles in the most uniform distribution in winter. Cd as a carcinogenic heavy metals in 、PM4.7-1.1, PM9.0-5.8 were detected. In the corresponding human organs, the pharynx, the first grade bronchial, the two level of bronchial, the end of the bronchus, the fine bronchus are micro deposition. The non carcinogenic risk index of Pb, Cu, Mn, Sb, Fe, V for children, adult female and adult male was less than 1, the different gender groups of all ages are non carcinogenic risk. The total combined children’s index is close to 1, and there is a risk of children’s health. Cd, Co carcinogenic elements of the human body does not have the risk of cancer. Children with a higher value index, the health of children, should be the attention of social groups. |
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