The air quality index (AQI)

The air quality index (AQI) 

Launched in 2014 with outline ‘One Number – One Color -One Description’ 

Central pollution control board has developed this Air Quality Index in consultation with IIT-Kanpur and air quality-professionals and experts

is an index for reporting air quality on a daily basis.

 It is a measure of how air pollution affects one's health within a short time period.

 The purpose of the AQI is to help people know how the local air quality impacts their health. 

Who calculate and what 

The Environmental Protection Agency (EPA) calculates the AQI for five major air pollutants, for which national air quality standards have been established to safeguard public health.

 8 things that measure

Particulate Matter (PM10), Particulate Matter (PM2.5),

 Nitrogen Dioxide (NO2), 

Sulphur Dioxide (SO2), 

Carbon Monoxide (CO), 

Ozone (O3), 

Ammonia (NH3), 

and Lead (Pb).

 

PM 2.5 refers to the concentration of microscopic particles less than 2.5 microns in diameter and PM 10 refers to the concentration of particles less than 10 microns in diameter.

The higher the aqi , the greater the level of air pollution and the greater the health concerns. 

.

 

How is AQI calculated?

 

Usa 

Different countries use different point scales to report air quality. For instance, the United States uses a 500 point scale, wherein rating between 0 and 50 is considered good. 

Rating between 301 to 500 range is deemed hazardous. 

India

India too follows that the 500 point scale. Every day monitors record concentrations of the major pollutants. 

These raw measurements are converted into a separate AQI value for each pollutant (ground-level ozone, particle pollution, carbon monoxide, and sulfur dioxide) using standard formulae developed by EPA. 

Air Quality Index Categories

 

Good (0–50) - Minimal Impact

 

Satisfactory (51–100) - May cause minor breathing difficulties in sensitive people.

 

Moderately polluted (101–200) - May cause breathing difficulties in people with lung disease like asthma, and discomfort to people with heart disease, children and older adults.

 

Poor (201–300) - May cause breathing difficulties in people on prolonged exposure, and discomfort to people with heart disease

 

Very Poor (301–400) - May cause respiratory illness in people on prolonged exposure. Effect may be more pronounced in people with lung and heart diseases.

 

Severe (401-500) - May cause respiratory issues in healthy people, and serious health issues in people with lung/heart disease. Difficulties may be experienced even during light physical activity.

 

Why is AQI important?

 

Awareness of daily levels of air pollution is important, especially

for those suffering from illnesses caused by exposure to air pollution.

 

Objectives of Air Quality Index (AQI)

• Comparing air quality conditions at different locations/cities.
• It also helps in identifying faulty standards and inadequate monitoring programmes.
• AQI helps in analysing the change in air quality (improvement or degradation).
• AQI informs the public about environmental conditions. It is especially useful for people suffering from illnesses aggravated or caused by air pollution.

 

What Instrument is used to Measure Air Quality?

Some of the instruments used are given below.

1. PCE-RCM 05
2. PCE-HFX 100
3. PCE-RCM 8

How Does PM get into the air?

PM stands for Particulate Matter. It is a term used to define a mixture of solid particles and liquid droplets found in the air. Some particles such as dust, smoke, soot are visible to the naked eye, but other particulate matters are too small that they are only visible in the electron microscope. Some of the sources of PM are construction sites, fire, fields, unpaved roads etc. Most of the particles are formed due to complex reactions of chemicals such as sulfur dioxide and nitrogen oxides. These are the pollutants emitted by automobiles, industries, power plants etc.