【R】通过浓度计算AQI

#IAQI(PM2.5)=0-50-100-150-200-300-400-500---------

#PM2.5=0-35-75-115-150-250-350-500

PM25_IAQI=ifelse(

  #IAQI=0-50

  (PM25_24_48_72>=0 & PM25_24_48_72<35),(50-0)/(35-0)*(PM25_24_48_72-0)+0,

  ifelse(

    #IAQI=50-100

    (PM25_24_48_72>=35 & PM25_24_48_72<75),(100-50)/(75-35)*(PM25_24_48_72-35)+50,

    ifelse(

      #IAQI=100-150

      (PM25_24_48_72>=75 & PM25_24_48_72<115),(150-100)/(115-75)*(PM25_24_48_72-75)+100,

      ifelse(

        #IAQI=150-200

        (PM25_24_48_72>=115 & PM25_24_48_72<150),(200-150)/(150-115)*(PM25_24_48_72-115)+150,

        ifelse(

          #IAQI=200-300

          (PM25_24_48_72>=150 & PM25_24_48_72<250),(300-200)/(250-150)*(PM25_24_48_72-150)+200,

          ifelse(

            #IAQI=300-400

            (PM25_24_48_72>=250 & PM25_24_48_72<350),(400-300)/(350-250)*(PM25_24_48_72-250)+300,

            ifelse(

              #IAQI=400-500

              (PM25_24_48_72>=350 & PM25_24_48_72<500),(500-400)/(500-350)*(PM25_24_48_72-350)+400,

              ifelse(

                #IAQI>500

                (PM25_24_48_72>=500),500,NA

              )

            )

          )

        )

      )

    )

  )

)