The Air Quality Index (AQI) (also known as the Air Pollution Index (API) or Pollutant Standard Index (PSI) is a number used by government agencies to characterize the quality of the air at a given location.
Air pollution is the introduction of chemicals, particulate matter,
or biological materials that cause harm or discomfort to humans or
other living organisms, or damages the natural environment into
the atmosphere. The atmosphere is a complex dynamic natural gaseous system
that isessential to support life on planet Earth. Stratospheric ozone
depletion due to air pollution has long been recognized as a threat to
human health as well as to the Earth’s ecosystems.
The Air Quality Index (AQI) (also known as the Air Pollution
Index(API) or Pollutant Standard Index(PSI) is a number used by
government agencies to characterize the quality of the air at a given
location and reporting daily air quality. As the AQI increases, an
increasingly large percentage ofthe population is likely to experience
increasingly severe adversehealth effects. To compute the AQI requires
an air pollutantconcentration from a monitor or model. The function used to
convert from air pollutant concentration to AQI varies by pollutant, and is
different in different countries. Air quality index values are divided
into ranges, and each range is assigned a descriptor and a color code.
Standardized public health advisories are associated with each AQI
range. An agency might also encourage members of the public to take
public transportation or work from home when AQI levels are high.
Limitations of the AQI
Most air contaminants do not have an associated AQI. Many countries
monitor ground-level ozone, particulates, sulphur dioxide, carbon
monoxide and nitrogen dioxide and calculate air quality indices for
Causes of Poor Air Quality
The AQI can worsen (go up) due to lack of dilution of air emissions
by fresh air. Stagnant air, often caused.