Title: Analysis on Variation Features of Concentration of Main Air Pollutants in Tangshan
Abstract: The quality of air is closely related to the comprehensive competitiveness of a city. Analyzing and discussing the changing rules of various air pollutants and finding out the leading factors affecting the current environmental quality are of great significance for further improving the urban environment and formulating reasonable and economic environmental protection measures. Based on the daily concentrations monitoring data of six major air pollutant(PM<sub>2.5</sub>, PM<sub>10</sub>, SO<sub>2</sub>, NO<sub>2</sub>, CO and O<sub>3</sub>) at six monitoring sites of Tangshan urban from 2015 to 2017, the characteristics of the concentration changes of six major air pollutants in Tangshan with time and space were analyzed by statistical analysis. The results showed that the ratio of air quality standard days increased year by year from 2015 to 2017 in Tangshan.The average concentration of SO<sub>2</sub> was lower than the second standard in the Environmental Air Quality Standard, the average concentration of NO<sub>2</sub>, PM<sub>10</sub> and PM<sub>2.5</sub> was higher than the second standard in the Environmental Air Quality Standard; the Over-standard rate range of the average concentration of NO<sub>2</sub> was the highest, ranging from 64% to 93%, that of SO<sub>2</sub> was the lowest, ranging from 0% to 3%; The days of PM<sub>2.5</sub> as the main pollutant were the most, ranging from 102 to 217 days, and the days of SO<sub>2</sub> as the primary pollutant were the least, ranging from 0 to 3 days; the concentrations of SO<sub>2</sub>, NO<sub>2</sub>, PM<sub>10</sub>, PM<sub>2.5</sub> and CO were the highest in winter and O<sub>3</sub> in summer.