Air quality

Figure 1. Air quality differs drastically around the world; in densely polluted cities with poor pollution control, face masks are sometimes necessary.[1]

Air quality is an important factor in a person's quality of life.[2] When air quality is high, the outdoors are fresh and enjoyable. This corresponds to a greater well-being of individuals, including enhanced health and happiness.

Poor air quality causes poor visibility, difficulty breathing, disease and even death.[3] Many Asian countries are suffering the most from poor air quality, and experience daily smogs, increasing the risk of death from lung and heart disease.[4] Many people in developing countries around the globe suffer from health effects from poor air quality as countries aggressively increase their industry. This air pollution often, but not always, comes from burning of different fuels.

Many countries have an air quality index (AQI), which shows how toxic the air may be to the population and specific groups of people. The World Air Quality Index Map below:


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Air quality is worsened when various pollutants are introduced into the air, especially in high quantities over a small area. These pollutants can be emitted by many sources, but the most dominant contributor within cities are vehicles burning gasoline and other oil products. The burning of coal also produces many harmful pollutants, however in most places around the world coal is burned relatively far away from cities, so the air pollution from coal plants has a less visible effect on air quality.

Figure 2. Smoggy vs clear day in Calgary.[5]

The pollutants that deteriorate air quality include nitrogen oxides, sulfur oxides, particulate matter, volatile organic compounds, and more. These are considered primary pollutants, since they are emitted directly into the atmosphere. A majority of them also react in the air to form what are called secondary pollutants, and these include ozone and peroxyacyl nitrates (PANs).[6] A combination of many of these leads to the formation of smog and photochemical smog, which may stay over a given location for an unsafe amount of time.

Visit the pages below for more information on pollutants and how they affect health and the environment.


  1. Flickr [Online], Available:
  2. City of Calgary. (August 6, 2015). Air quality [Online], Available:
  3. Office for National Statistics. (August 6, 2015). Air pollution and its impact on people's health and well-being [Online], Available:
  4. EJAP. (August 6, 2015). Air pollution in Asia [Online], Available:
  5. via the Calgary Herald.
  6. LSC Atmospheric Sciences. (Accessed July 23, 2015). Secondary Pollutants [Online], Available: