Air quality in Markham

Air quality index (AQI) and PM2.5 air pollution in Markham

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What is the current weather in Markham?

Weather icon
WeatherBroken clouds
Wind4 mp/h
Pressure29.9 Hg

live aqi city ranking

Real-time Canada city ranking

#cityUS AQI
1 Cardston, Alberta


2 Okotoks, Alberta


3 Nakusp, British Columbia


4 Wild Rose, Alberta


5 Municipal District of Bighorn No 8, Alberta


6 Canmore, Alberta


7 Calgary, Alberta


8 Airdrie, Alberta


9 Banff, Alberta


10 Amos, Quebec


(local time)


live Markham aqi ranking

Real-time Markham air quality ranking

#stationUS AQI
1 118 Risebrough Circuit


(local time)


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What is the current air quality in Markham?

Air pollution levelAir quality indexMain pollutant
Moderate 57 US AQIPM2.5



PM2.5 concentration in Markham is currently 3 times the WHO annual air quality guideline value

Health Recommendations

How to protect from air pollution in Markham?

An IQAir mask icon Sensitive groups should wear a mask outdoors
An IQAir purifier icon Sensitive groups should run an air purifier
An open window icon Close your windows to avoid dirty outdoor air
A man cycling icon Sensitive groups should reduce outdoor exercise


Markham air quality index (AQI) forecast

DayPollution levelWeatherTemperatureWind
Tuesday, Mar 21

Moderate 62 US AQI

Human face indicating AQI level
Weather icon39.2°32°
Wind rotating 139 degree

11.2 mp/h

Wednesday, Mar 22

Moderate 81 US AQI

Human face indicating AQI level
Weather icon39.2°32°
Wind rotating 321 degree

13.4 mp/h

Thursday, Mar 23

Good 23 US AQI

Human face indicating AQI level
Weather icon35.6°28.4°
Wind rotating 301 degree

8.9 mp/h

Friday, Mar 24

Moderate 61 US AQI

Human face indicating AQI level
Weather icon100%44.6°32°
Wind rotating 107 degree

24.6 mp/h


Moderate 57 US AQI

Human face indicating AQI level
Weather icon50%39.2°32°
Wind rotating 266 degree

26.8 mp/h

Sunday, Mar 26

Good 30 US AQI

Human face indicating AQI level
Weather icon39.2°30.2°
Wind rotating 356 degree

8.9 mp/h

Monday, Mar 27

Good 11 US AQI

Human face indicating AQI level
Weather icon41°30.2°
Wind rotating 42 degree

4.5 mp/h

Tuesday, Mar 28

Good 9 US AQI

Human face indicating AQI level
Weather icon37.4°28.4°
Wind rotating 303 degree

17.9 mp/h

Wednesday, Mar 29

Good 12 US AQI

Human face indicating AQI level
Weather icon41°28.4°
Wind rotating 132 degree

6.7 mp/h

Thursday, Mar 30

Good 6 US AQI

Human face indicating AQI level
Weather icon100%46.4°32°
Wind rotating 185 degree

15.7 mp/h

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Historic air quality graph for Markham

How to best protect from air pollution?

Reduce your air pollution exposure in Markham


What is the air quality index of Markham?

Markham is a city in the Regional Municipality of York in Southern Ontario, Canada. It is approximately 30 kilometres north east of Ontario. According to a 2016 census, Markham had a population of approximately 330,000 people.

At the beginning of 2021, Markham was enjoying a period of “Good” quality air with a US AQI reading of just 29. This is according to the classifications suggested by the World Health Organisation (WHO).

The recorded level of the PM2.5 pollutant was 7.1 µg/m³. With levels as low as these, windows and doors can be safely opened to allow the ingress of fresh, clean air. Outdoor activities of all types can be enjoyed without fear.

What is the main source of air pollution in Markham?

Air pollution can be of natural origin (volcanic eruption, pollen, forest fires, etc.), but it mainly comes from human or anthropogenic activities (transport, individual and collective heating, industries, agriculture, incineration of household waste, domestic activities etc. Pollutants can be divided into two main categories which are primary and secondary.

Primary pollutants are directly released into the air by an identified source, most of the time linked to human activities (road traffic, industry, heating, agriculture, etc.). They can include nitrogen monoxide (NO), sulphur dioxide (SO2), carbon monoxide (CO), heavy metals (lead, arsenic, cadmium and nickel), organic compounds volatiles (VOC’s) and Polycyclic Aromatic Hydrocarbons (PAHs including benzo (a) pyrene).

Secondary pollutants are not directly released into the air. They are formed from chemical reactions between different primary pollutants, already present in the air.

For example ozone (O3), which is formed when nitrogen oxides and hydrocarbons react under the influence of ultraviolet radiation from the sun (this is partly why ozone is more present in the spring and in summer). Acid rain, which is the result of the acidification of the rainwater having captured various pollutants but also the dry deposition of these pollutants sulphur dioxide and nitric oxides (SO2 and NOx).

Because of its proximity to Ontario, many people will commute on a daily basis between the two places. This will create a lot of emissions which will reduce the quality of air overall. Recorded levels of pollution are always at their highest during the rush-hour periods.

There are several main arterial roads which pass through or run very close to the city centre which again reduces the quality of air.

What is the pollution level in Markham?

Environment Canada monitors the state of the air quality and issues warnings if they suspect the air quality is going to pose a threat to the local residents.

They would issue a special air quality statement for several communities in the province including Newmarket, Georgina, Northern York Region, Vaughan, Richmond Hill and Markham. This would be issued due to the possibility of deteriorating air quality. According to Environment Canada, hot and sunny conditions cause increasing ground-level ozone concentrations in the area. Individuals may experience symptoms such as increased coughing, throat irritation, headaches or shortness of breath. Children under 14 years of age, senior citizens, and those with pre-existing health problems, cardiovascular or lung disease, such as asthma, are especially at risk.

It is estimated that in Markham, due to travelling to work and school, per passenger is produced annually 1,236.84kg of carbon dioxide (CO2). 56.81 trees need to be planted for each passenger to produce enough oxygen to cover that.

What can be done to improve the air quality in Markham?

Ontario regulates air pollutants from a variety of sources, including local industrial and commercial facilities, to limit exposure to substances that can harm human health and the environment.

If a business releases any pollutants into the air, it must follow Ontario Regulation 419/05 by complying with any standards that may apply.

Air quality standards set the limit for pollutants released into the air. They are enforceable (they are recognised in the eyes of the law). To see if a company is meeting the standards, the local authorities compare the estimated maximum concentration of the pollutant at its point of contact with the air quality standard for that pollutant.

If a company can show that the maximum concentration of the pollutant it releases into the air does not exceed the limit established by the standard relating to this pollutant, Regulation 419/05 does not impose any other requirements on it. Most businesses in Ontario meet general air quality standards, which is one reason why the air quality is overall very good.

What are the effects of breathing Markham’ poor quality air?

One of the most dangerous pollutants is the microscopic PM2.5 particulate matter. It is a complex mixture that may contain soot, smoke, metals, nitrates, sulphates, dust, water and tyre rubber and brake dust. It can be directly emitted, as in smoke from a fire, or it can form in the atmosphere from reactions of gases such as nitrogen oxides.

The size of particles is directly linked to their potential for causing health problems. Small particles (known as PM2.5 or fine particulate matter) pose the greatest problems because they bypass the body’s natural defences and can get deep into the lungs and potentially your bloodstream. Exposure to such particles can affect both your lungs and your heart.

Long-term exposure to particulate pollution can result in significant health problems including increased respiratory symptoms, such as irritation of the airways, coughing or difficulty breathing. Decreased lung function and aggravated asthma. The development of chronic respiratory disease in children and the development of chronic bronchitis or chronic obstructive lung disease. Irregular heartbeat and nonfatal heart attacks are more frequent because of the polluted air. Premature deaths of people with pre-existing heart or lung disease, including death from lung cancer are conditions that are exacerbated because of these deadly microscopic particles.

Does the weather affect the air quality in Markham?

Hot, humid weather may elevate pollution levels and as such, individuals may experience symptoms such as increased coughing, throat irritation, headaches or shortness of breath, according to the special air quality statement. Hot and sunny conditions are expected to cause increasing ground-level ozone (O3) concentrations.

Markham air quality data attribution

Contributors 1

Data sources 1

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