Outlier Detection Of Profile Data Based On Spatial And Temporal Analysis

The record and analysis of the air pollution situation in China is one of the main objects in the study,with the analysis of the changing tendency in air pollution from different perspectives.Another purpose of the research is the assessment of the factors that affect the pollution in China.PM2.5 is chosen to be the index in the study to reflect the situations of the city air pollution.Specifically,cluster analysis and wavelet analysis is used to research the PM2.5 pollution of 15 cities in northern China,using the PM2.5 data of the selected cities from 2014 to 2015.In terms of the situation of PM2.5 pollution in the cities,the data of PM2.5 was collected monthly for the record.Using MATLAB,the study identified the outliers and the clusters of the PM2.5 data,as well as the geographic areas with the similar air pollution conditions,and the factors that could affect the change of the pollution data for the further work of pollution management,through the spatial and temporal analysis of the PM2.5 data.In terms of temporal analysis,to some extent,selected cities gain the higher level of air pollution at the beginning and the ending period of every year,compared with the rest of time.Meanwhile,in terms of spatial analysis,there is no significant relation between the air pollution condition and the geographic location.Moreover,the factors like climate and industry features of the selected city would have impacts on its pollution condition.For example,low temperature and low wind speed would facilitate the pollution change.And the areas with the similar industrial structure would have the similar pollution condition in PM2.5.In a word,this study conducts the direct observation and analysis of PM2.5 data,reflecting the air pollution conditions in the selected cities,in order to finish the research of the air pollution situations of the cities in northern China from spatial and temporal perspectives and summarize the possible factors related to the city air pollution.The study supports the efforts of precaution and reduction of PM2.5 pollution in northern China.The analysis could be helpful for the future studies of the PM2.5 pollution of cities in China and the relation between the pollution and the related factors.