| Zhengzhou city, the Capital of Henan Province, located in the central region of China, is the national pivot of goods by the way of road and railway. Accompanied with the two-digit growth of Zhengzhou's GDP, rapid expansion of urban area and its inhabitants, the emission of pollutants has increased sharply since 1996. Since the implementation of the project, "pollution control and meeting criterion for water and air", the air quality after 2000 is significantly better than that before it. Based on the data monitoring and investigating from 2001 to 2004, the status of current air quality and the cause of air pollution are assessed and analyzed, respectively, to supply the scientific base for building the national model city of environmental protection.PurposeBy analyzing the air data monitoring from 2001 to 2004, we describe the status and trend of the quality of the air in Zhengzhou city, investigate the resource of air pollutants and the cause of air pollution, and then suggest the strategies to improve the quality of the air in Zhengzhou city with reference to the lessons of other cities in home and abroad.Materials and Methods1,Analysis of monitoring and investigating data. We learn the characterized spatial-temporal distribution of the densities of the air pollutants and assess the current quality of the air in Zhengzhou city by analyzing the monitoring and surveying data of the air pollutants emission in the key investigated enterprises.2,Distribution of monitored places and pollutants monitoring. Monitored places includes 7 sites and pollutants monitored contain SO2, NO2 and PM10.3,Analyzing Methods. All monitoring sites in urban area are automatically monitored and analyzed with SO2,NO2 and PM10 by the use of ultra-violet fluorescence, chemical-illuminant,β-ray.4,Assessing Criterion. Criterion for this paper is the second order Secondary Standard in GB3095-1996《Ambient air quality standard》and ranked with the Air Pollution Index.5,Assessing methods. The air quality in Zhengzhou city is assessed with the single and comprehensive pollution index, air pollution standardized load factor and the Air Pollution Index through transforming the daily average value, into monthly and yearly average value, of every monitoring site.6,Statistical methods. We create the database with the monitoring data and Excel 2003 and analyze the data with SAS10.0 system. Descriptive Data: we describe the emission of air pollutants, estimate the current level of air quality, and plot the temporal tendency and characterize the spatial distribution, in the period of time between 2001-2004 in Zhengzhou city with statistical tables and graphs. Analytical Data: the impact of seasons and years on the quality of air were estimated with x2 Test. The variances of the quarterly and monthly densities of SO2,NO2,PM10 are tested at significant level(α=0.05),with Rank sum Test (Wilcoxon) and Spearman Rank Correlation Coefficient respectively.Results1 Consumption of Coal and emission of Pollutants:During 2001 to 2004, Consumption of Coal in urban area fluctuated slightly and the emission of SO2 had a small growth while the emission of smoke and dust decreased. At 2004 differed significantly the Consumption of Coal and emission of Pollutants among the urban area and counties. The highest consumption and emission took place in the urban area, and the districts in Zhengzhou decreased in the order of Gongyi,Dengfeng,Xinmi,Xingyang and Xinzheng2,The yearly change of the air quality from 2001-2004. The comprehensive air pollution index varies from 2.26-2.56. According to the chi-square test (x2检验), the air quality in 2002 is significantly worse than that of the other 3 years, and there is no significant difference among 2001,2003,2004; the air quality just reached tertiary standard in GB3095-1996 in the line with the yearly average concentrations of pollutants.Another thing worthy of being noticed is that: although the yearly average concentrations of PM10 gradually decreased in past 4 years, they all exceeds the second rank in GB3095-1996; in addition, the yearly average concentrations of SO2 and NO2 climbed, and they are close to secondary standard in GB3095-1996 in 2004. As a whole, the quality of air Zhengzhou city is not deserved to be optimistical.3,The seasonal distribution of the air quality. It is apparent for the seasonally characterized distribution of the air quality in Zhengzhou urban districts. (1) The days of air pollution ranked with API take up U type, and the pollution of the air in Spring and Winter is more serious than that in Summer and Autumn; in the view of chi-square test, the severity of air pollution decreases from Winter, Spring,Autumn and Summer. (2) During 2004 in all districts of Zhengzhou city, the concentrations of pollutants tested with Rank Sum Test (Wilcoxon) differ significantly in 4 quarters, and the monthly concentrations of pollutants, which take up V type, in Spring and Winter are higher than those in Summer and Autumn.4,The spatial distribution of the air quality. In 2004, the primary source of pollutants came from PM10 in all monitoring sites but Henan university of medical science in which site it is SO2. The severity of comprehensive pollution in all monitoring sites declined in the order of Henan university of medical science, the factory of cigarette, the factory of textile machinery, the monitoring station, the school of bank, the company of supplying water; The severity of comprehensive pollution in Zhengzhou region decreased from Gongyi and Xinmi, to Xinzheng and Xingyang, to Dengfeng in which the air quality is the best and met the primary standard. 5,The correlation of the pollutants: The analysis of Spearman Rank Correlation for the yearly average concentrations of pollutants in 2004 shows that: the Rank Correlation Coefficients between SO2 and NO2, SO2 and PM10, NO2 and PM10 are 0.776 (P < 0.05), 0.790 (P < 0.05) and 0.580 (P>0.05), respectively.Conclusions:1,The types of air pollution in Zhengzhou city. Currently, the primary types of air pollution in Zhengzhou city are coal, which is the leading resource of PM10,SO2 in air. They are firstly and secondly from the burning of industrial and civil coal, respectively. Additionally, with the shot development of urban transportation and then the mushroom of automobiles, exhaust from cars is increasingly becoming another ignorable source of pollutants. For example, the yearly concentration of NO2 increases during 2001-2004 and it reaches tertiary standard in GB3095-1996 in 2004.2,The causes of air pollution in Zhengzhou city. The continuous pressure on the air environment is from energy consuming structure primarily comprising of coal and the increase of coal-burning by the inhabitants giving off the pollutants at low altitude. The contribution of exhausts from cars to pollution is next to the burning of coal. The main reasons for failure to PM10 criterion result from the continual stopping of decontaminating facilities in enterprises, the burning of stalks in autumn, the sandstorms, the sand-dust caused by the construction industries and the deterioration of vegetation. In addition, the charge for pollution is too low, in comparison with the expense of decontaminating, to keep enterprises from polluting.3,Strategies to improve the quality of the air in Zhengzhou city. (1)Sensibly adjusting the energy structure and speeding up the replacement of coal with the clean energy such as gas and electricity. (2) Building up the ecology industry and the circling economy, taking full advantage of the materials and energy available, decreasing the emission of pollutants while increasing the usage of wastes. (3) Alleviating the air pollution in urban areas by ameliorating the layout of industrial enterprises. (4) Mitigating the pollution of exhaust from cars by furthering the exploitation of gas bus and establishing the high efficient public transportation system. (5) Improving the ecology environment and dropping the harmful gas through forbidding the burning of the stalks and reinforcing the vegetation in urban areas.
|
PDF Full Text Request