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.

Air pollution is made up of gases, liquids, and particles that come from many sources like vehicle exhaust, industrial processes, energy generation, home and building heating, wood burning, and construction dust. Most air pollution we experience is created by vehicle exhaust and industrial emissions. Several sources of air pollution also generate greenhouse gases that contribute to climate change.

On this page:

Air pollution and your health

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

  • The concentration of pollutants
  • 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)
  • Irritate eyes, nose and throat
  • Aggravate pre-existing illnesses like asthma, chronic obstructive pulmonary disease (COPD) or angina

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

Air Quality Health Index (AQHI)

The Air Quality Health Index (AQHI) is a scale to help you understand the impact of air quality on your health. 

The AQHI measures air quality on a scale of 1 to 10 and assigns health risk levels (low, moderate, high or very high). The higher the number, the greater the health risk and need to take precautions.

If you or someone in your care is sensitive to air pollution, it can be helpful to know how to modify outdoor activities with different AQHI readings.

Air Quality Health Index Health Risk Level General Population At Risk Population*
1-3 Low Ideal air quality for outdoor activities Enjoy your usual outdoor activities
4-6 Moderate No need to modify your usual outdoor activities unless you experience symptoms such as coughing and throat irritation. Consider reducing or rescheduling strenuous activities outdoors if you are experiencing symptoms.
7-10 High Consider reducing or rescheduling strenuous activities outdoors if you experience symptoms such as coughing and throat irritation. Reduce or reschedule strenuous activities outdoors. Children and the elderly should also take it easy.
Above 10 Very High Avoid strenuous activities outdoors. Children and the elderly should also avoid outdoor physical exertion. Avoid strenuous activities outdoors. Children and the elderly should also avoid outdoor physical exertion.

 *People with heart or breathing problems are at greater risk. Follow your doctor or health care provider’s advice about exercising and managing your condition.

Exposure to air pollutants can cause a range of symptoms. People with lung or heart disease may experience increased frequency and/or severity of symptoms, and increased medication requirements. Follow your health care provider’s advice about exercise and managing your condition.

To monitor the day-to-day AQHI for Waterloo Region, visit Kitchener Air Quality Health Index.

For custom AQHI notifications to your smartphone, download the free mobile app WeatherCAN from Environment and Climate Change Canada.

Air quality advisories 

Environment and Climate Change Canada and Air Quality Ontario, issue air quality messages to encourage the public to protect their health as it relates to air pollution. These messages are based on the Air Quality Health Index (AQHI) forecasts and observations.

A Special Air Quality Statement (SAQS) is issued when the AQHI is expected to be high risk level (7 or higher).

An Air Quality Advisory (AQA) is issued when the AQHI is expected to reach, or has reached, a very high risk level (10 or higher), due to wildfire smoke.

For custom AQHI notifications to your smartphone, download the free mobile app WeatherCAN from Environment and Climate Change Canada.

Wildfire smoke and your health

Wildfires are not common in Waterloo Region. However, smoke from wildfires in other areas can affect local air quality. With climate change, wildfires may become more frequent in Canada. This will impact local air quality more often. Everyone’s health can be affected from heavy smoke.

When the air is smoky, take steps to protect your health

  • 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.
    • Download the free WeatherCAN app to check the AQHI regularly to help you plan your day and breathe easier.
  • Spend less time outside.
  • Keep indoor air clean.
    • Use the best quality air filter that your ventilation system can handle based on 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, a well-fitted respirator type mask 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 irritation and discomfort are common and usually disappear when the smoke clears.
  • 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.

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
    • Live with lower income
    • Have lower education
    • Experience housing insecurity
    • Experiencing uncertain employment
  • 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 impacts may be greater for people who live close to a wildfire. People may experience worsening mental health impacts such as:

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

Protect yourself

The higher the Air Quality Health Index (AQHI) number and rating, the greater the health risk. You can protect yourself or someone in your care in the following ways:

  • Check your local weather forecasts so you know when to take extra care.
  • If you are taking medication or have a health condition, pay close attention to medical symptoms and take a break if necessary.
  • Exercise when air pollution is low. 
    • Active people of all ages who exercise or work outdoors are at increased risk to the health effects posed by air pollution.
    • Use the AQHI to figure out the best times to be active outdoors.
  • Reduce energy use by turning air conditioners to a higher temperature and turn off lights, computers and other electrical appliances when not in use.
  • Limit your exposure to air pollution by avoiding source emissions, where possible, such as on busy roads or heavy traffic areas.
  • Stay indoors and keep windows closed.
  • Eliminate indoor air pollution sources such as tobacco smoke.
  • Limit outdoor pollutants from entering your home by replacing your furnace/central air filters every 3 months.
    • Be sure to follow manufacturer’s or service technician's recommendations.
  • Avoid using chemical-based products in your home that can affect indoor air quality.
    • Choose less-toxic cleaners, paints, finishes and glues.
    • Look for products labeled “VOC-free”, “zero-VOC” or “low-VOC”.

Certain people may experience more serious health effects at lower levels of air pollution.

  • For people with cardiovascular disease or lung diseases, such as asthma and chronic obstructive pulmonary disease (COPD), pollution can worsen medical conditions and lead to increased medication use, doctor and health care provider visits, emergency room visits, and hospital visits.
  • Children and teenagers may be at higher risk from outdoor air pollution because they are usually more active outdoors. They are also more likely to have asthma, and their lungs are still developing.
  • Older adults may be more affected by air pollution because they are more likely to have pre-existing lung and cardiovascular disease.

Additional resources

Contact Us