The Regulating Effect And Influencing Factors Of Urban Recreation Forests On PM_2.5 And PM₁₀

The rapid development of industrialization,the rapid increase in the number and use of motor vehicles,make atmospheric particulate matter the primary pollutant of air quality in Nanchang City,and the urban green space has become the ecological city construction and maintenance environmental safety due to the effects of cooling and humidification,dust and pollution interception.An important means.This paper takes 90%,60%,30%of the canopy forests in Nanchang Global Park as the research object,6 broad-leaved forest samples,2control samples,and 5 coniferous forest samples.It is still one.The atmospheric particulate matter concentration was monitored for 5 days in each season,and monitored every 2 hours for 24 hours.The changes of atmospheric particulate matter with different particle sizes in different forest types and different seasons were analyzed from three angles of time,space and meteorological factors.The effects of temperature,humidity,wind speed and rainfall on the concentration of particulate matter were also discussed.The structural differences between coniferous forest and broad-leaved forest were also observed by scanning electron microscopy.The research results are as follows:?1?According to the national ambient air quality standards,PM_2.5 and PM₁₀concentrations in the global park and PM_2.5 concentrations in the summer all meet the secondary standard.In the remaining seasons,PM_2.5 and PM₁₀ have different levels,and the winter exceeds the standard.Spring is second.The seasonal variation of PM_2.5 concentration is:winter>spring>autumn>summer;theseasonalvariationofPM₁₀is:winter>spring>summer>autumn.The daily average change is characterized by"low daytime,high nighttime".In spring and winter,the degree of particulate matter pollution is high.PM10is the main pollutant in summer and night.PM_2.5 is the main pollutant in the noon of summer and the early morning and morning of spring,autumn and winter.?2?Recreational forest has better PM_2.5 reduction ability than PM_10,and PM_2.5.5 has the strongest reduction ability in summer,PM₁₀0 has the strongest reduction ability in autumn,and the weakest particulate matter reduction ability in winter.In the different time periods,the overall range of PM₁₀'s high value area distribution is greater than PM_2.5,and the spring PM_2.5 and PM₁₀ high value areas are the most distributed,followed by winter.In the morning,the high-value area was mostly distributed inside and outside the broad-leaved forest.Before and after 16:00,the high-value area gradually turned to the coniferous forest.?3?The effects of temperature,humidity and wind speed on the concentration of particulate matter in different forest types are different in different seasons.Humidity has the greatest influence on PM_2.5 and PM₁₀ in broad-leaved forest,and wind speed affects PM_2.5 and PM₁₀ in coniferous forest.Maximum,the effect of temperature on the two forest types is most pronounced in spring.Rainfall has the greatest impact on PM_2.5 and PM₁₀.According to the national secondary standard,it exceeds the standard before rain and does not exceed the standard after rain.Through the comparison of the structural characteristics of common plant leaf surfaces in the park,coniferous forests affect the results of the particulate matter than broadleaf forest.