LL--31311. NAAQS and1. NAAQS and

2. Air Pollution Indices2. Air Pollution Indices

Air Pollution and ControlAir Pollution and Control

(elective(elective--I)I)

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.

NEW NAAQS 2009NEW NAAQS 2009

What is the Air Quality Index?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.

DefinitionDefinition• 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

Use of AQIUse of AQI1. 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

Types of IndicesTypes of IndicesShort 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

Air Pollution ParametersAir Pollution Parameters

•• SPMSPM

•• SOSO22

•• COCO

•• NONO22

•• OO33

Criteria for standardised indexCriteria 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

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)

Determination of indexDetermination of index1) 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.

2.2)

3) In the third method, air pollution index is calculated from five sub-indices.

Each sub-index is obtained by assigning sub-index values for particular ranges of pollutants.

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

Rating scale for indicesRating 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

Other rating scalesOther rating scales

1. Good , acceptable, unsatisfactory, unhealthy

2. Good, satisfactory, unsatisfactory, unhealthful

3. Light , moderate, heavy, alert

4. Good, normal, moderate, heavy, severe

Air Quality IndexAir Quality Index

Theory questionsTheory questionsQ1. Write short notes on

1. NAAQS

2. Air Quality Index (AQI)