Change Trends and Corresponding Meteorological Character of Air Pollition in Beijing

Abstract

Based on the monitoring data of air quality and meteorological data from 2003 to 2009 in Beijing, the change of air quality and pollutants concentration are analyzed, and their relationship with meteorological conditions are figured out. The results showed below.(1)The annual average value of API (Air Pollution Index) decreased from 2007 gradually, and the value of 2008 is equal to 86.3% of 2007. As to monthly changing trend of API, the value in April is highest, and is lowest in august. API in summer is lowest relatively in all-year, and it is worst in spring. (2)The pollutants concentration of PM2.5, SO2, NO2, and NOX showed decreasing trends from 2006 to 2009. The monthly changing trends of PM2.5, SO2, NO2, and O3 were different. The monthly average concentrations of NOX SO2, NO2 and NOX were lowest in July, while the high values appeared in different month.(3)Correlation between pollutant concentration and meteorological conditions are figured out: SO2, NO2 and NOX are negative related to temperature, wind speed and sunlight hours and positive related to humidity, while O3 is adverse. PM2.5 is well related to relative humidity and cloud cover. PM2.5, SO2, NO2 and NOX are all positive related to wind speed.(4)The air quality and pollutant concentration displayed significant in different under each wind direction. When north wind blows, the average value of API is lowest relatively and south wind is adverse. The concentration of PM2.5, SO2, NO2 and NOX are lower when Beijing is controlled by the north wind or north-west wind.