The document discusses the National Ambient Air Quality Standards (NAAQS) set by CPCB to regulate atmospheric pollution levels. It explains the Air Quality Index (AQI) as an indicator of air quality based on various pollutants and the calculation methods for determining air pollution indices. The document also outlines the purpose and types of indices for public information regarding air pollution levels over short and long terms.

1. L-31
1. NAAQS and
2. Air Pollution Indices
Air Pollution and Control
(elective(elective-I)

2. Understand Air Quality Standards
• An air quality standard is the
maximum level of atmospheric pollution
allowed at one time in a geographical
area.
• These standards, which are called the
National Ambient Air Quality
Standards (NAAQS), are set by the
CPCB.
• These are designed to set limits on the
amount of pollution allowed in the air
and to force those who pollute the air to
stop.

3. NEW NAAQS 2009

8. What is the Air Quality Index?
• The Air Quality Index (AQI) is an
indicator of air quality, based on air
pollutants that have adverse effects on
human health and the environment.
• The pollutants are ozone, fine
particulate matter, nitrogen dioxide,
carbon monoxide, sulphur dioxide.

9. Definition
• Air pollution Index is defined as a
scheme that transforms the
(weighted) values of individual air
pollution parameters in to a single
number or set of number
• As a result we get an equation which
transforms the parameter values by
means of numerical manipulation
into simple and precise form

11. Use of AQI
1. It helps in informing public about air
pollution in a particular area.
2. It helps in comparing air pollution
levels in different cities
3. It may be used for development for
a system for avoidance or
management of a severe air
pollution episode

12. Types of Indices
Short term indices :- These are
usually intended to inform the public
about daily changes in air pollution
levels.
Long term Indices:- These are
intended to evaluate changes in air
quality over periods of several years
or more.
These are useful for assessing
effectiveness of enforcement of
policies

13. Air Pollution Parameters
•
•
•
•
•
SPM
SO2
CO
NO2
O3

14. Criteria for standardised index
1. Easily understood by public
2. Includes major pollutants
3. Calculated in simple manner
4. Rest on reasonable scientific basis
5. Spatially meaningful
6. Consistent with perceived air
pollution levels

15. 7. Exhibit day to day variation.
8. Relate AAQS and goals
9. Relate to episode criteria.
10. Can be forecast a day in advance
(If possible)

16. Determination of index
1) In this method we try to relate the existing
pollution levels of various pollutants
related to their ambient air quality
standards, with the standards being
assumed as the reference base line for
each pollutants into a percentage of the
standard.
The air pollution index is then obtained by
adding percentages for several pollutants
considered.

18. 2)
2.

19. 3) In the third method, air pollution
index is calculated from five subindices.
Each sub-index is obtained by
assigning sub-index values for
particular ranges of pollutants.

21. 4) In fourth method, known as the
maximum type, only one pollutant index
(the highest one) among the several
pollutants is reported.
5) In the fifth method only two pollutants
i.e. PM and SO2 are taken into account
while calculating the air pollution index.
6) In sixth method , only one major
pollutant e.g. ozone concentration is
taken as basis for reporting air pollution
index

22. Rating scale for indices
Index value
Remark
0-25
Clean air
25-50
Light air pollution
50-75
Moderate air pollution
75-100
Heavy air pollution
> 100
Severe air pollution

23. Other rating scales
1. Good , acceptable, unsatisfactory,
unhealthy
2. Good, satisfactory, unsatisfactory,
unhealthful
3. Light , moderate, heavy, alert
4. Good, normal, moderate, heavy,
severe

24. Air Quality Index

25. Theory questions
Q1. Write short notes on
1. NAAQS
2. Air Quality Index (AQI)