NAQI:- National Air Quality Index for India

NAQI
National Air Quality Index for India
There are Six (6) AQI categories like GOOD, SATISFACTORY, MODERATELY POLLUTED, POOR AIR QUALITY, VERY POOR AIR QUALITY, SEVERALLY POLLUTED. These AQI are integrated with AQI Sub-index (which is a range in real numbers). These six categories are decided based on Ambient concentration values of air pollutants & their likely health effects. The AQI sub index  and health impacts (health breakpoints) are evolved for eight (8) pollutants like PM10, PM2.5, NO2, SO2, CO, O3, NH3, Pb. 

NAQI standard are prescribed for these 8 pollutants for short term exposure (24hrs).  Sub-index is calculated based on ambient concentrations of these air pollutants. It is to be noted that AQI Sub-index is linear function of ambient concentrations of these 8 air pollutants.
The worst Sub-index determines Overall AQI.


AQI                         Possible Health impacts  
                        or health break point


Good -                    Minimum Impact
(0-50)

Satisfactory -        Minor Breathing
(51-100)                discomfort to
                               sensitive  persons

Moderately Polluted-  Breathing discomfort  
(101-200)                     to persons having Heart
                                      or Lung disease, to older
                                      ones & to children's

Poor -                     Breathing discomfort to
(201-300)              persons on prolonged
                               exposure 

Very Poor -            Respiratory illness to
(301-400)              people on prolonged
                               exposure 

Severe -               Respiratory effects even on
(>400)                  healthy people


One observation means one AQI calculated
for daily Ambient Air Quality data at
one Air Monitoring Station.



Air Pollutant      AQI Sub-index     Ambient        
                                                          concentration                                                                      of PM2.5

PM2.5                      100                  60 μg/m3
PM2.5                       75                   45 μg/m3
PM2.5                       50                   31μg/m3