| Air pollution is currently considered to be the main influencing factor of global burden of diseases?GBD?.In the past ten years,with the increasing smog pollution,the research of outdoor fine particles(PM2.5)has gradually been paid more and more attention.Outdoor calculated parameters of PM2.5 are important foundations for determining indoor PM2.5 load and air filter device selection.,which directly affects the room filtering effect and equipment investment Under this background,it is necessary to develop PM2.5 research on the determination method of outdoor calculated parameters.This paper obtains the original meteorological data of 367 cities for 6 years?2014-2019?from the National urban air quality real time release platform.In addition,the PM2.5 concentrations changing characteristics of time dimension and space dimension have been discussed.The hourly concentration downward cumulative curvature curve and "inflection point" have been used for annual pollution analysis and evaluation.Finally based on the concept "not guaranteed",the determination method of PM2.5 outdoor calculated parameters is determined.The main research contents are as follows:First,the national air quality monitoring site distribution map and the layout of different stages have been obtained from the National urban air quality real time release platform.The similarities and differences of Chinese and American Air quality classification index standards are discussed.Secondly,the hourly outdoor PM2.5 concentration of 367 cities nationwide from 2014 to 2019 is counted,and the characteristics of the spatiotemporal variation of outdoor PM2.5 concentration in Beijing are analyzed.Finally,based on the concept of “non-guaranteed”,the paper analyzed the health effects of long-term and short-term exposure,and discussed the correlation between the concentration change and the daily average concentration.Determining the concentration type suitable for outdoor calculation parameters from the short-term exposure and PM2.5 pollution representative.By revealing the trend of the hourly concentration change of the whole year,the " inflection point" of the outdoor PM2.5 hourly concentration trend is analyzed to determine the time when the PM2.5 outdoor calculated concentration is "not guaranteed".Combining with the " inflection point " of the cumulative curve trend of PM2.5 hour concentration in multiple cities,we determined the unguaranteed hours for PM2.5 outdoor calculated concentration,and obtained the PM2.5 outdoor calculated concentration of 367 cities nationwide.This study on the calculated outdoor concentration of PM2.5 can provide a reference for determining the calculated outdoor concentration of indoor PM2.5 pollution control design of urban buildings. |
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