Analysis Of Temporal And Spatial Distribution Characteristics And Forming Factors Of PM_2.5 In Major Cities In Hebei Province

Particulate matter is the one of major air pollutants in Hebei province,and in the particulate matter,PM_2.5 specific surface area are greater than PM₁₀,and also more toxic,beside PM_2.5 in the air is less likely settlement,this endangers the health of each residents.This study was to investigate the temporal and spatial distribution of PM_2.5 in Hebei province,and the contact between PM_2.5 and other pollutants,which lay the foundation for source apportionment,causes of high PM_2.5 concentration analysis,relationship between pollutant emissions and air quality,establishment the analog systems of response relationship between emissions and air quality,feasibility analysis of pollution reduction pathway.This paper use the data of 2013,2014 and the first half of 2015 from ambient air monitoring network which set up with a total of 207 stations in 11 cities in Hebei province,combine with the geographical and meteorological conditions in Hebei province,we analysis that the temporal and spatial distribution of PM_2.5 in Hebei province and the key city in Hebei province Shijiazhuang and Tangshan,we obtained the following conclusions.1)First,we statistically analysis the PM_2.5 concentrations in 2013 and 2014 in Hebei province,The PM_2.5 concentration of Hebei province reached the maximum value of the year in January,and reached the minimum value of the year in the September;Meanwhile,We analysis the daily variation of PM_2.5 of Shijiazhuang and Tangshan in January,April,July and October in 2014.In addition to April the highest PM_2.5 concentrations occur in the evening or early morning and lowest in the afternoon in Shijiazhuang,and the highest PM_2.5 concentrations occur at 10 am in April.The highest PM_2.5 concentrations occur at 10 am and 9 pm in January and October in Tangshan,and the highest PM_2.5 concentrations occur at 7 am to 9 am in April and July.2)We explores the relevance between conventional pollutants and PM_2.5 and relevance between PM_2.5 and NH₃ and VOCs.PM₁₀ had a proportional relationship with PM_2.5.SO₂,NO₂ and CO shows a positive correlation with PM_2.5.Ozone shows a negative correlation with other pollutants.VOCs we supplementary monitored show a positive correlation with PM_2.5.NH₃ shows a negative correlation with PM_2.5 in date changes,but NH₃ have no correlation with PM_2.5 in hour changes.5)Finally,we analysis the influence of weather static stability index and wind speedon PM_2.5.The larger the static stability weather index,the more prone to air pollution and the longer the duration of air pollution.Gale plays a key role for pollutant diffusion.The indicators show different degrees of decline when the wind speed is large.