| PM2.5 is a particle size of less than 2.5 μm,the visibility,air quality has an important impact on human health.The influence of concentration on one hand by the weather and wind speed and a series of meteorological conditions,on the other hand is also affected by human activities,is special at the weekend,working days and holidays human,production and lifestyle differences caused by differences of particle concentration.Therefore,the concentration of PM2.5 and the corresponding meteorological data and weather data in the study were selected from 2014 to 2016 in Beijing City,the first overall variation characteristics of PM2.5 concentration in the city,the weekend effect And vacation effect analysis,and then,the holiday effect of PM2.5 concentration in urban and suburban areas,and the weekend effect under different seasons,different weather conditions and different wind speed were discussed,draw the following conclusions:(1)From the past three years,the weekend effect in Beijing city PM2.5concentration,and the city north and northwest is the resident population intensive areas,human activities have a greater impact,the weekend effect of the concentration of PM2.5 is obvious,and the weekend effect in the South and southwest is weak.(2)The burning of fireworks during the Spring Festival and national day travel the number of the traffic flow and the increase of the concentration of PM2.5 during the Spring Festival and National Day holidays were greater than,a holiday effect is obvious.(3)In PM2.5 concentration showed the character of the weekend > working day at0:00-15:00,and the concentration of PM2.5 on the outskirts of 24 hours showed less than the working day weekend.This is mainly due to the weekend vehicle limit line,the traffic flow increases,the concentration of PM2.5 increased.The mean PM2.5concentration on urban and suburban areas are more than the weekend that there were mean,the weekend effect obviously.In different season,urban and suburban areas in all seasons all have the weekend effect,which is most obvious in autumn.In addition,the concentration of PM2.5 in urban and suburban areas showed a significant holidayeffect.(4)From the view of different weather conditions,whether urban or suburban concentration,sunny PM2.5 showed the weekend effect.While the haze had no effect on the weekend,the main reason is because of health considerations,the people in the haze days out less,the influence of PM2.5 concentration is low,resulting in PM2.5without the weekend effect.Four from the division of view,the concentration of PM2.5 City sunny in spring,summer and winter have obvious effect on weekends,and the weekend effect of haze days only in winter.The weekend effect of PM2.5concentration in the suburb of sunny spring,summer and winter,haze days appeared in autumn and winter.(5)From the view of different wind conditions,whether urban or suburban,when the wind speed is less than 3.3m/s,the concentration of PM2.5 showed a weekend evident effect,while the wind speed is greater than 3.3m/s,there is no weekend effect.From the four division,urban wind speed less than 1.6m/s or greater than 3.3/s,the concentration of PM2.5 has obvious effect in the spring weekend and fall;when the wind speed is 1.6-3.3m/s,the weekend effect appeared in the season.On the outskirts of wind speed is less than 1.6m/s,the weekend effect of PM2.5 concentration in spring,autumn and winter;At the wind speed is 1.6-33m/s,the weekend effect occurred in summer,autumn and winter.When the wind speed was greater than3.3m/s,the weekend effect occurred only in spring. |
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