AIR
QUALITY INDEX - ENVIRONMENT
News: Air quality in Delhi poor, no major
relief predicted
What's
in the news?
●
Delhi’s air quality was recorded in the
poor category for the third consecutive day and a major improvement is unlikely
over the next few days, according to monitoring agencies.
Key
takeaways:
●
The air quality around Delhi University
was recorded at 273 (poor) in the morning hours, while the IIT area in New
Delhi was at 173 today.
Air
Quality Index (AQI):
●
It was launched by the central government
in 2014 as part of the Swachh Bharat
campaign, the AQI was to help simplify the common understanding of
pollution.
○
An expert
group comprising medical professionals, air quality experts, academia,
advocacy groups and others was constituted and a technical study was awarded to
IIT Kanpur.
○
IIT Kanpur and the Expert Group
recommended an AQI scheme.
●
The AQI transforms complex air quality
data of various pollutants into a single number (index value), nomenclature and
colour.
●
The colour-coded
AQI index helps the public and the government understand the condition of
the air and what subsequent measures are to be taken to combat the situation,
based on its severity.
○
For a general understanding it is
considered as ‘One Number- One
Colour-One Description’ to know the air quality in a particular area.
Pollutants:
●
The pollutants measured include PM 10, PM 2.5, NO2, SO2, CO, O3, NH3 and
Pb.
Six
categories of AQI:
●
‘Good’ (0-50)
●
‘Satisfactory’ (50-100)
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‘Moderately polluted’ (100-200)
●
‘Poor’ (200-300)
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‘Very Poor’ (300-400)
●
‘Severe’ (400-500)
Calculation
of the index:
●
There are six or eight pollutants in the
affected air and each of these pollutants is given a weight based on a formula.
That weight depends on the kind of impact it has on human health.
●
The worst of these weights is given as
composite air quality, so instead of giving six different numbers and six
different colours, it throws up one single colour, one single number to denote
the overall impact.
●
Monitoring stations across the country
assess these levels.