Air Quality

Air quality is a measure of how clean or polluted the air is and has a direct impact on our health. We experience better air quality when there is less air pollution.

On this page:

Air pollution and your health

Air pollution is when outdoor pollutants can harm your health. These include tiny particles (PM2.5/PM10), ground‑level ozone (O3) and nitrogen dioxide (NO2).

The impact of air pollution will vary depending on factors such as:

  • How much pollution is in the air
  • How often and how long someone is exposed to pollutants
  • A person’s age and general health status

Poor air quality can:

  • Cause difficulty breathing (coughing and wheezing), headache, dizziness, tiredness
  • Irritate eyes, nose and throat
  • Aggravate pre-existing illnesses like asthma, chronic obstructive pulmonary disease (COPD) or angina

Air quality: who is most at risk?

Some people are more at risk of health problems when exposed to air pollution:

  • Older adults
  • Pregnant people
  • Infants and young children
  • People who work outdoors
  • People involved in strenuous outdoor exercise
  • People with an existing illness or chronic health conditions, such as:
    • Cancer
    • Diabetes
    • Mental illness
    • Lung or heart conditions

Over time, repeated exposures can increase the risk of heart attacks, strokes, lung disease and early death.

Find more information on wildfire smoke.

Using the Air Quality Health Index (AQHI)

The Air Quality Health Index (AQHI) can help you understand air quality and what it means to your health. The AQHI measures air quality on a scale of 1 to 10+. The higher the number, the greater the health risk and need to take steps to protect your health.

View the AQHI scale and related health messages

How to check the Air Quality Health Index (AQHI)

The AQHI can change often throughout the day. It is a good idea to check it a few times a day, especially before going outside.

Check the current AQHI

Download the free WeatherCAN app for custom notifications.

WeatherCAN app

Air quality alerts 

Environment and Climate Change Canada and Air Quality Ontario, issue air quality alerts. These alerts encourage people to protect their health when there is more air pollution (for example, an AQHI of 7 to 10+). 

You may hear these terms used in news reports or weather apps:

  • Special Air Quality Statement (SAQS) is when the AQHI is expected to reach the high-risk category (AQHI 7–10). 
  • Air Quality Advisory (AQA) is when the AQHI is expected to reach the very high-risk category (AQHI of 10+) because of wildfire smoke

Wildfire smoke and your health

Wildfire smoke contains fine particles that can harm your lungs, heart and other organs in your body. Even if fires are far away, wind can carry smoke to Waterloo Region and impact local air quality.

Smoke can impact your health even at very low levels. As smoke levels increase, so does your health risk. Air quality may be poor even if you can not see or smell smoke.

Take steps to protect your health from wildfire smoke

  • Check the Air Quality Health Index (AQHI) to help you decide if you should change your outdoor plans.
    • Air quality from wildfire smoke can change throughout the day as wildfire smoke moves in and out of the area.
  • Spend less time outside.
    • Stay indoors and keep windows and doors closed.
    • If it is too warm, turn on air conditioning. If you do not have air conditioning visit a Cooling and Clean Air Space.
  • Keep indoor air clean.
    • Use the best quality air filter that your ventilation system can handle. Always check the manufacturers' recommendations. Run the fan mode and put the system on recirculate. 
    • Use a portable air purifier or cleaner.
  • Do light activities only.
    • Avoid anything that makes you breathe hard.
    • Avoid strenuous activities like jogging, yard work or lifting heavy things.
  • Wear a well-fitting respirator (like an N95 mask). If you must spend time outdoors this can help reduce your exposure to the fine particles in smoke.
  • If you work outdoors, check with your provincial occupational health and safety association or your employer for safety information about wildfire smoke events.

Pay attention to how you feel

  • People respond differently to smoke.
  • Mild symptoms include eye and throat irritation, cough, runny nose and headaches. 
    • Drinking water can help your body cope with the smoke.
  • More severe symptoms include dizziness, heart palpitations, chest pains, wheezing and difficulty breathing.
    • Stop or reduce your activity level if breathing becomes uncomfortable or you or someone in your care feel unwell. 
    • Contact your health care provider if you develop severe symptoms.
  • Exposure to wildfire smoke can worsen health problems like asthma, chronic obstructive pulmonary disease (COPD) and congestive heart failure.
    • If you start to feel unwell, take a break or contact your health care provider.

Wildfire smoke: who is most at risk?

Check in on neighbours, friends and family, especially those more likely to be impacted by wildfire smoke. Share the AQHI health messages to help them protect their health from wildfire smoke.

Some people are more at risk of health problems when exposed to wildfire smoke:

  • Infants and young children
  • Older adults
  • Indigenous Peoples
  • Pregnant people
  • People who:
    • Smoke
    • Work outdoors, including wildland firefighters
    • Are involved in strenuous outdoor exercise
  • People with an existing illness or chronic health conditions, such as:
    • Cancer
    • Diabetes
    • Mental illness
    • Lung or heart conditions

Wildfires can impact mental health

Mental health effects may be worse for people living near a wildfire, especially those who must evacuate and move to another area. People may experience mental health impacts such as:

  • Anxiety
  • Depression
  • Post traumatic stress disorder (PTSD)
  • General distress caused by natural disasters and climate change

These free resources are available for anyone experiencing mental health problems. Don’t be afraid to reach out if you need help:

Additional resources

Air Quality Resources

Climate Change Resources

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