Spatial And Temporal Distribution Characteristics Of NO₂ In Beijing-Tianjin-Hebei Region In The Past 2009-2016 Years

NO₂ is one of the major atmospheric pollutants.It is also an important precursor in the formation of ozone,acid rain and photochemical smog.It has a serious impact on the quality of the atmosphere and endangers the human beings living in the atmosphere.By using the OMI data of the ozone layer observatory on the Aura satellite launched by NASA in the United States and using the software of ArcGIS and ENVI to process the downloaded OMI data,the column concentration distribution data of the NO₂ in Beijing,Tianjin and Hebei region are extracted.According to the measured concentration of the local monitoring points,and using the points corresponding to the latitude and longitude of the monitoring points,the corresponding NO₂ column concentration data are extracted.The correlation analysis between the concentration of NO₂ column and the measured concentration is analyzed,and the measured concentration of the Beijing Tianjin Hebei region is fitted by the correlation results and column concentration data,and the analysis is carried out.The results show that the distribution of NO₂ concentrations in the Beijing-Tianjin-Hebei region from 2009 to 2016 is extremely uneven.The low concentration areas are concentrated in Zhangjiakou City in the northwest and Chengde City in the north,while the high concentration regions are concentrated in Shijiazhuang,Xingtai,and Chongqing.Tangshan and Tianjin industries and the economically developed cities,while the concentration of cities in central Cangzhou and Hengshui cities are in the median area.Although the distribution of concentration and concentration in the area showed an imbalance,the distribution characteristics of NO₂ concentration in Beijing,Tianjin and Hebei did not change significantly in the past eight years.It is still the ratio of Shijiazhuang,Hengshui,Handan,and industry in the south of Beijing,Tianjin,Hebei.The concentration of developed cities in Tianjin and Tangshan is relatively high,but the area of high-concentration areas tends to decrease,and it can also be seen from the figure that the tendency of high-concentration areas to become contiguous is also becoming smaller.The results showed that the average proportion of the second industry in Beijing accounted for 21.6%of the GDP.At the same time,the correlation coefficient of second industry of Beijing and the NO₂ concentration was analyzed,and the correlation coefficient was 0.7945 and the correlation was good.One of the main reasons for the increase in the concentration of NO₂ in Beijing caused by the industrial production and emission of the city of Beijing.In addition,the number of motor vehicles and the large number of population are also the cause of the concentration of the NO₂.The proportion of the second industry in Hebei and Tianjin is more than 50%in the GDP.At the same time,the number of motor vehicles in several cities like Shijiazhuang,Xingtai,Handan with high NO₂ concentration in Hebei province and the change rate of the number of motor vehicles are analyzed.It is found that the population of these three cities accounts for more than 10%of the population of Hebei province.It can be concluded that 2009-2016 years in Tianjin and Hebei Province,and the main reason for the increase of NO₂ concentration is the emission of industrial production,the emission of motor vehicle exhaust and the increasing number of the population.