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Healthy Environments

Outdoor Air Quality

Each day you take roughly 20,000 breaths of air. The quality of that air has a significant impact on our health in the long and short-term. Outdoor air quality is affected by different types of air pollutants from a variety of sources, including vehicle emissions, energy production and usage, and wildfires. Recent data shows that air quality in Simcoe Muskoka has improved; however, air quality remains a concern and more can be done to reduce air pollution to make the air healthier for everyone.

You can protect yourself and those you care about by understanding how air pollution affects your health, and by taking actions to reduce exposure to air pollutants and to improve air quality in our community by:

  • understanding the Air Quality Health Index (AQHI) and Air Quality Alerts, which can keep you informed of current local air quality and help you make decisions to protect yourself and those you care about;
  • estimating your sensitivity to air pollution. If you have an existing heart or lung condition, speak with your health care provider about additional ways to protect your health when air pollution levels are high; and
  • learning how we can work together to improve air quality in Simcoe Muskoka.

The Simcoe Muskoka District Health Unit works to improve air quality and reduce exposure to air pollutants by:

  • sharing information and resources to keep you informed and healthy;
  • working with our partners and municipalities to promote healthy public policies, encourage community design for health and recognizing the health co-benefits of climate change action;
  • contributing to research on ways to reduce exposure to traffic-related air pollution through healthy community design; and
  • monitoring and communicating the health impacts of air quality in Simcoe Muskoka.

On this page you will find information and resources about outdoor air quality, air pollution and health, and strategies that everyone can take to reduce exposure to air pollution and improve air quality.  

NEW: For more information on Wildfire Smoke and Health, please click here

Adverse health effects from air pollution depend on many things including the length of time, the amount, and type of pollution you are exposed to. While everyone is affected by air pollution, each person reacts differently. Children, older adults, those who are pregnant, and those with existing diabetes, heart or lung conditions, are at a greater risk of negative health impacts from air pollution. More information to help you assess your sensitivity to air pollution can be found here.

Gases and fine particles that make up air pollution impact the heart, lungs, brain and other organs, and can lead to illness, hospitalization, and premature death. Long-term exposure to air pollution can increase the risk of developing heart and lung diseases and cancer. Short-term exposure to certain air pollutants, even at low levels of exposure, can:

  • cause headaches;
  • make it harder to breathe;
  • irritate your eyes, lungs, nose and throat; and
  • worsen existing heart and lung conditions, including asthma, and increase the risk of heart attack, and stroke.

If you, or someone around you experience severe symptoms, seek medical attention as soon as possible. Immediately call 911 if you think you or someone else is, or could be having a heart attack, stroke, or experiencing another medical emergency.

Weather conditions, human emissions, and wildfires interact and contribute to the levels of air pollution (made up of gases and chemicals). Important air pollutants include; ground-level ozone (O3), fine particulate matter (PM2.5), nitrogen dioxide (NO2), sulphur dioxide (SO2) and carbon monoxide (CO). More information on air pollutants can be found from the World Health Organization and Government of Canada Websites.  

The majority of air pollution is caused by human activity. For example, the way we make and use energy, our transportation patterns, waste management and industry all contribute to emissions of air pollution and greenhouse gases that can be harmful to our health. Everyone (individuals and organizations) has a role to play in reducing air pollutants to promote and protect health of our community. More information on how to take action on air quality is identified below. 

On most days, air quality is very good in Simcoe Muskoka, with low air quality health risks.  However, there are some places, such as near major roads and highways, and days where we experience higher air quality health risks.

Traffic-Related Air Pollutants 

Traffic-related air pollutants (TRAP) are emissions related to traffic. They are a main source of air pollution in Ontario. TRAP are higher near and on major roads and highways. Learn more about TRAP at Public Health Ontario and SMDHU’s HealthSTATS.  


If we idle our car for more than 60 seconds, we are contributing to poor air quality and climate change.  A car's exhaust contains particulate matter (PM), volatile organic compounds (VOCs), nitrogen oxides (NOx), carbon monoxide (CO), and carbon dioxide (CO2). By reducing idling by five minutes a day, you will save about 44.9 litres of fuel ($55.36 at $1.25/L) and 103 kg of greenhouse gas emissions in a year. 

Check with your local municipality to see if they have an idling control by-law.

Wildfire Smoke

Wildfire smoke is made up of a variety of gases and particles that are harmful to health at any level. Wildfire smoke can be carried hundreds and thousands of kilometers, affecting local air quality. It can be difficult to predict wildfires and their impact on local air quality. Wildfire smoke events typically occur from April to October. For more information on wildfire smoke, air quality and health, visit here.

The air quality health index (AQHI) is a tool to help you understand local air quality and what it means for your health. It is designed to help you make informed decisions to protect your health and the environment by:

  • limiting short term exposure to air pollution;
  • adjusting physical activity levels during episodes of increased air pollution; and
  • reducing personal contribution to air pollution.

The AQHI provides real-time, and 2 days forecast of air quality and offers suggestions on how you can protect your health when poor air quality levels pose low, moderate, high and very high health risks.  

What does AQHI measure?

The AQHI measures three common air pollutants know to harm human health: ground-level ozone (O3), fine particulate matter (PM2.5), and nitrogen dioxide (NO2).

These three pollutants have significant impacts on human health, even at low levels of exposure, especially among people with pre-existing heart and lung conditions.

The AQHI does not measure aeroallergens like pollen, which can also impact your health.

How does the AQHI Work?

The AQHI provides a measure of air quality on a scale from 1 to 10+. The higher the number, the higher the pollution levels and the health risk and the greater need to take precautions. 

The index describes the level of health risks associated with each number.

  • 1 to 3 = ‘Low’ health risk
  • 4 to 6 = ‘Moderate' health risk 
  • 7 to 10 = ‘High’ health risk
  • 10+ = ‘Very high’ health risk  

The AQHI also provides health messages tailored for both high risk individuals and the general public, as well as provides recommendations on how people can improve the air quality that they breath.  

Air Quality Health Index and Health Messages

When should I use the AQHI?

The AQHI can help you and those you care about be aware of the health risks of poor air quality and steps to take to protect your health.  Check the AQHI daily to receive real-time air quality levels and forecasts to help plan your outdoor activities.  If you or someone you know has existing health conditions or are sensitive to air pollution, follow the health messages for at risk populations.

Where can I find the AQHI?

For more information about the AQHI, visit the Government of Canada's AQHI website.

When air quality health index levels are anticipated to be high, an air quality alert will be jointly issued by the Environment and Climate Change Canada and the Ontario Ministry of Environment and Climate Change. There are two types of air quality alerts that may be issued:

  • Special Air Quality Statements (SAQS) are issued when high risk air quality is forecasted for one to two hours.
  • Smog and Health Advisories (SAHA) are issued when high risk air quality is forecasted for three or more hours.

The purpose of air quality alerts are to advice people to take steps to avoid unnecessary exposure to air pollution to protect their health. The alerts also inform industries and the public to take steps to reduce their emissions.

You can subscribe to receive air quality alerts by visiting:

Climate Health Connection

Our climate is changing and these changes are affecting human health and wellbeing in Simcoe Muskoka. Climate change, air pollution, and their combined impact on air quality and public health are closely connected.

  • The sources of air pollution and climate change are the same. Emissions of greenhouse gases and other pollutants not only affect air quality but are also the root cause of climate change.
  • Climate change can increase the levels of air pollutants dangerous to human health.
    • Rising temperatures associated with climate change increases the creation of ozone and fine particulate matter.
    • The increase in severe thunderstorms, drought, and extreme heat increases the risk of wildfires which can significantly impact air quality and human health, even hundreds of kilometers away.
  • Climate change will also increase the amount and timing of aeroallergens, such as pollens and moulds due to increased productivity of plants and prolonged growing seasons associated with rising carbon dioxide levels and temperatures. This can activate allergies and pre-existing asthma.

Actions to reduce greenhouse gases (climate change mitigation) and other air pollutants from the atmosphere will directly improve air quality while simultaneously fighting climate change. This will lead to improved health and wellbeing and reduce other negative health impacts associated with climate.

Action on Air Quality

We can make a difference to improve air quality in Simcoe Muskoka to support healthy communities. Taking action to improve air quality is a win-win situation. It will improve health and wellbeing, fight climate change, and make our communities more liveable.

At an individual level, small actions add up to create a big impact. Consider the things you can do to improve air quality to help make the air healthier for everyone. This can be things like maintaining home furnaces to use less energy, not idling our cars, or using active transportation (e.g., biking or walking) to get to school or work instead of driving. These actions can also save us money. Check out the Clean Air Partnerships 20/20 The Way to Clean Air Program for more ways to cut down home energy use and vehicle emissions.

Large-scale change is also required. As a community, we can improve community design for health. We can implement policies and invest in strategies to support low-carbon transportation systems, energy-efficient buildings, green power generation, and better waste management practices to reduce key sources of outdoor air pollution. These strategies will also increase our community's resilience to climate change.

You can support these large-scale changes by staying informed, getting involved, and speaking out. Your voice is important.

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