Government of Nova Scotia Government of Nova Scotia Nova Scotia, Canada


Air Quality Health Index (AQHI)

What can I learn from the AQHI?

What the AQHI Measures

The AQHI measures the health risks associated with three air pollutants in outdoor air:

  1. ground-level ozone (O3)
  2. particulate matter (PM2.5)
  3. nitrogen dioxide (NO2)

These pollutants may come from local sources or may blow in on the wind from other parts of Canada and the US. Research has shown these three pollutants can harm human health.

What the AQHI Does Not Measure

The AQHI does not measure the effects of pollen, dust, odour, or humidity on health.

Dust particles are larger than the fine particulate matter we do measure-PM2.5 and PM10. The mucus in your nose traps large dust particles when you breathe. We measure the smaller particles that are more hazardous to health. These smaller particles can get deep into our lungs and can cause or aggravate health problems.

Pollen and humidity are measured separately by Environment Canada.

Where the AQHI Takes Measurements

The AQHI does not measure air quality in every neighbourhood.

AQHI monitoring stations are located throughout the province to give a good general picture of air quality in Nova Scotia. Specific local events-such as a fire, a factory, or busy roads-may make local air worse.

Development of the AQHI

In 2001, the federal government began development of the Air Quality Health Index (AQHI) in partnership with provincial governments and non-governmental organizations across Canada. The index is based on research by Health Canada. The AQHI differs from past air quality indices (AQI) which do not focus on human health and are typically based on levels of individual air pollutants.

AQHI information for other provinces is also available.