The adverse health effects of air pollution are well established and have been reported in research studies for over 30 years. However, multiple variables make pinning down exact health outcomes to specific air pollution exposure very complicated. These variables include concentrations of air pollution and its various components, exposure time and individual response. For example, there is no specific health data available on air pollution exposure corresponding to length of an individual’s stay in any given location (say, for example, an afternoon in Delhi? 2-4 years? A lifetime?) Nevertheless, there is much we do know and as scientific measurements become more sophisticated and evidence mounts, we gain better information about how air pollution and its various components affect our health.

In March 2014 the World Health Organization reported that in 2012, seven million people died worldwide as a result of air pollution exposure. The finding more than doubled the WHO’s previous estimates on mortality due to air pollution exposure and placed air pollution as the world’s largest single environmental health risk.

What we know about air pollution and health. Some facts:

  • Air pollution increases the risk of respiratory and heart disease.
  • Both short and long-term exposure to air pollutants has been associated with health impacts.
  • People who are already ill are more severely impacted by air pollution.
  • Children, the elderly and poor people are more susceptible to the harmful effects of air pollution.
  • There is mounting evidence that exposure to air pollution has long-term effects on lung development in children.
  • Outdoor air pollution is carcinogenic
  • Particulate matter (PM) is the component of air pollution that causes the most damage to human health

Feeling sick? It might be the air…
The following is a summary of the effects of particulate matter, the specific component of air pollution that causes the most damage to health. This level of information can be found on each of the other common components of air pollution. A good source of information on the individual air pollutants can be found in a booklet produced by the U.S. EPA.


Particle pollution and health
What are the effects and who is most at risk?
Particulate matter in air pollution can cause a number of health problems and has been linked with illnesses and deaths from heart and lung disease. These effects have been associated with both short-term exposures (usually over 24 hours, but possibly as short as one hour) and long-term exposures (years).  Groups particularly sensitive to particle pollution include people with heart or lung disease, older adults, and children.

Long-term exposures such as those experienced by people living for many years in areas with high particle levels have been associated with problems such as reduced lung function and the development of chronic bronchitis and even premature death.

Short-term exposures to particles (hours or days) can aggravate lung disease, causing asthma attacks and acute bronchitis, and may also increase susceptibility to respiratory infections. In people with heart disease, short-term exposures have been linked to heart attacks and arrhythmias. Healthy children and adults have not been reported to suffer serious effects from short-term exposures, although they may experience temporary minor irritation when particle levels are elevated.

Click here to see a useful info-graphic on PM 2.5, the smallest particles of particulate matter,  and its effect on health (from the  Environmental Performance Index put out by Yale and Columbia Universities).

Symptoms: Who may feel symptoms caused by particulate pollution and what are they?
The color-coded chart below developed by the US Environmental Protection Agency (corresponding to the U.S. AQI measurements put out by the US embassy in Delhi) illustrates the portion of the population that may experience health effects due to particulate matter, at varying levels of AQI measurements.

AQI chart on Particle pollution

Notice that with an AQI in the hazardous column (301-500) the entire population may experience health effects due to exposure to particulate matter.

  • Healthy people may experience temporary symptoms such as irritation of the eyes, nose, and throat; coughing; phlegm; chest tightness; and shortness of breath.
  • People with lung disease may not be able to breathe as deeply or as vigorously as normal and may experience coughing, chest discomfort, wheezing, shortness of breath, and unusual fatigue.
  • People with heart disease may experience chest pain, palpitations, shortness of breath, and fatigue. Particle pollution has also been associated with cardiac arrhythmias and heart attacks.

For how to protect yourself from exposure to air pollution see our links to pages: activity guidelines; masks and home air filters.

In-depth information about the following pollutants is also covered in the EPA booklet. CARBON MONOXIDE; SULFUR DIOXIDE; OZONE Remember, the color-coded charts in these reports relate to the AQI format for reporting air pollution. These can be used directly with the AQI measurements from the U.S. Embassy in Delhi, as they use this format, or you can convert raw numbers of specific components of air pollution by using the AQI converter and then applying this number to the charts.

For an additional discussion on air pollution and health risks, see the below article from Dr. Richard Saint Cyr.
Air pollution and risk of death—not as bad as you think? Perspective on the numbers from Dr. Richard Saint Cyr.