Air Quality Health Index (AQHI)
The air we breathe, whether inside or outside, plays an important role in our overall health. With the recent issues around outdoor air quality and wildfires, it is important to understand how air quality is measures, how it affects our health, and how to protect others and ourselves.
In Canada, we use a measurement called the Air Quality Health Index (AQHI) which is a value calculated from measuring a combination of air pollutants including ozone (O3), particulate matter (such as pollen and car exhaust), and nitrogen dioxide (NO2). Other countries, such as US, UK, China, and Australia include sulphur dioxide (SO2) in their index (a product of burning fossil fuels at power plants and industrial facilities).
Canada uses the AQHI over other air quality indices as it combines the effects of air pollution mixtures into a single measure, as opposed to addressing each pollutant separately. While air quality indices may be beneficial for identifying a “safe” level of air pollution below a specific threshold, the AQHI provides the risk based on negative health effects to individuals.
Regardless of what is collected, the goal of these air quality indexes is to communicate a measure of the air quality in a region, the health risk associated with the index reading, and a health message for each category for general and “at risk” populations.
Wildfire Smoke
In Canada and around the world, wildfires are a significant contributor to poor air quality and increased air pollution levels. Due to the complex mixture of gases, particles, and water vapor produced in a wildfire, they can affect individuals over a large area, even at low levels. Air quality can be decreased even if you cannot see or smell smoke.
Symptoms of smoke exposure:
Mild/common symptoms that can be managed without medical intervention:
Headaches
Mild cough
Runny nose
Eye, nose, throat irritation
More serious symptoms that may require medical attention/911
Dizziness
Chest pain
Severe cough
Shortness of breath
Wheezing and asthma attacks
Irregular heart beat
Who is at risk?
As with most respiratory illnesses, those with pre-existing conditions (asthma, lung disease, heart conditions) are at a higher risk of developing health problems. Other groups can include seniors, pregnant individuals, infants and young children, people who work outdoors, people involved in strenuous outdoor exercise, those suffering from cancer, diabetes, and mental illness.
How to Protect Ourselves
Pay attention to the Air Quality Health Index, special air quality advisories, and other indicators of smoke levels in your area. Be sure to limit outdoor activity and strenuous physical activities. Individuals can also check with local health organizations to receive guidance of working safely outdoors.
For our homes, keeping windows and doors closed, as long as temperatures are comfortable, can prevent the pollution from entering the home. If available, using the recirculation setting on our HVAC systems (car or home) to prevent smoke from entering.
Another key aspect is to use a good high-quality filter in your ventilation system. The effectiveness of a filter is provided by a Minimum Efficiency Reporting Value (MERV) value, developed by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers or ASHRAE as it is more commonly known. Ratings of 13 or higher will provide a superior level of protection for homes by filtering the small particles out of the air; so long as your system can handle the filter, a higher MERV rating means more work on the ventilation system to move air. The highest MERV rating is 16 which filters out more than 95% of particles 0.3 microns and larger.
Many households where air quality is a concern, due to existing health issues or sensitivities, may find it beneficial to have a portable High Efficiency Particulate Air (HEPA) filter for specific rooms to add an additional filtration effect to remove air pollutants. HEPA filters remove 99.97% of dust, pollen, mold, bacteria, and airborne particles 0.3 microns or smaller (most hazardous particles). While there is a multitude of filtration devices available online or in-store, if you are looking for a HEPA filtration device, be sure to check for the certification number, as all HEPA filters must pass a performance test as outlined by ASHRAE, the Institute of Environmental Sciences and Technologies, and International Organization for Standardization (ISO). Note, HEPA filters cannot be “cleaned” or re-used. This is a “red-flag” for products claiming so, especially if you are shopping online.
Lastly, keep yourself hydrated and check on others who are in your care or live nearby that may be more vulnerable to smoke or poor air quality.
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