City report · Ontario, Canada
Ajax Air quality today
Air quality in Ajax currently reads AQI 14 (Good): Air quality is satisfactory for everyone.
AQI 14
Air quality right now
Good
- PM2.5, fine particles (µg/m³)
- 2.6
- tree cover
- 23.4%
- trees in this area
- 73.5K
- more trees needed
- 20.7K
Measured across a 2 km radius around Ajax, ON, Canada (12.57 km²), from a satellite image of Sep 12, 2026. Lower AQI is better: 0–50 is Good, above 300 is Hazardous.
Ajax · AQI 14 (Good)
Ajax's tree count comes to 73,513 trees across 12.57 km², 7 points below the 30% tree-cover level considered healthy for this area, so roughly 20,735 more trees would close the gap.
Air quality detail
Air quality in Ajax today: AQI 14, Good
Main pollutant: PM2.5 · Observed Nov 11, 12:00 local time via OpenAQ ground stations, US EPA index. Values in µg/m³.
Ground station · Pickering, 3.3 km away
Health signal
Air quality is satisfactory for everyone.
PM2.5
2.6
PM10
—
NO₂
—
O₃
—
SO₂
—
CO
—
Data: OpenAQ · AirGradient, Moo Home
- Outdoor exercise
- A good day to be active outside
- Windows
- Open them to air the house
- Mask
- Not needed
- Air purifier
- Not needed
Over the last 7 days, the CAMS air-quality model put Ajax's daily AQI at 29 on average, from 9 on Nov 9 to an hourly peak of 56 on Nov 4.
This is the US EPA AQI. How it differs from Canada's AQHI
Where Ajax stands: the most polluted cities in the world right now · the cleanest
Tree cover detail
Tree cover in Ajax: Below target
23.4% tree cover against a 30% healthy-neighborhood target, across 12.57 km².
Trees in this area
73,513
Target trees
94,248
More trees needed
20,735
CO₂ if planted / yr
456.2 t
Deforestation · 2001–2025
How much forest has Ajax lost?
Since 2001, the area within 10 km of Ajax has lost about 154 hectares of forest (about 220 football pitches): 2.9% of the forest it had in 2000. Most of it (85%) was deforestation, forest cleared for good, mainly for towns and roads.
2017: satellite photo from August 2017 of a 5 × 5 km area in the city center.
- Forest lost since 2001
- 154 haabout 220 football pitches
- Share of its forest
- 2.9%of what there was in 2000
- Cleared for good
- 131 hadeforestation: turned into farms, mines or towns
The worst year was 2017, when about 13 hectares of forest were lost.
Hectares of forest lost each year
Show the figures as a table
| Year | Cleared for good | Can grow back | Total |
|---|---|---|---|
| 2001 | 3 ha | under 1 ha | 4 ha |
| 2002 | 2 ha | under 1 ha | 3 ha |
| 2003 | 8 ha | under 1 ha | 9 ha |
| 2004 | 9 ha | under 1 ha | 10 ha |
| 2005 | 5 ha | under 1 ha | 6 ha |
| 2006 | 9 ha | 3 ha | 12 ha |
| 2007 | 6 ha | 2 ha | 8 ha |
| 2008 | 4 ha | 2 ha | 6 ha |
| 2009 | 2 ha | under 1 ha | 2 ha |
| 2010 | 10 ha | under 1 ha | 10 ha |
| 2011 | 13 ha | under 1 ha | 13 ha |
| 2012 | 5 ha | under 1 ha | 5 ha |
| 2013 | 7 ha | under 1 ha | 7 ha |
| 2014 | 5 ha | under 1 ha | 6 ha |
| 2015 | 3 ha | under 1 ha | 3 ha |
| 2016 | 5 ha | under 1 ha | 6 ha |
| 2017 | 10 ha | 3 ha | 13 ha |
| 2018 | 10 ha | under 1 ha | 11 ha |
| 2019 | 2 ha | under 1 ha | 2 ha |
| 2020 | under 1 ha | under 1 ha | 1 ha |
| 2021 | 2 ha | under 1 ha | 2 ha |
| 2022 | under 1 ha | under 1 ha | under 1 ha |
| 2023 | 5 ha | under 1 ha | 6 ha |
| 2024 | 4 ha | under 1 ha | 5 ha |
| 2025 | under 1 ha | 4 ha | 5 ha |
What is causing deforestation around Ajax?
- Towns and roadscleared for good77% · 118 ha
- Farms, pasture and plantationscleared for good8.1% · 12 ha
- Loggingcan grow back3.8% · 6 ha
Also: unknown causes.
Causes for 2025 are estimates, based on what caused forest loss in the same places up to 2024.
Forest gained and lost, 2000–2020
- Forest in 2000
- 7,250 ha
- Forest in 2020
- 7,560 ha
- Overall change
- +304 hamore forest than in 2000
Comparing satellite maps from 2000 and 2020, the forest around Ajax grew from about 7,250 hectares to 7,560 hectares, a net gain of about 304 hectares (+4.2%). New forest grew on about 522 hectares, while 218 hectares were lost.
These 2000 and 2020 maps, from the University of Maryland, count any land with trees taller than 5 m as forest, including plantations and orchards. Forest that was cut or burned and had grown back by 2020 counts in both years, so the loss here is smaller than the yearly figures.
These figures cover everything within 10 km of the city center, a wider area than the report above, because forest is usually lost at a city's edges.
Source: Hansen/UMD/Google/USGS/NASA, Global Forest Change (GFC-2025-v1.13); causes: WRI/Google DeepMind drivers of forest loss; both CC BY 4.0, summed by Airleaf for each area. Forest gained and lost 2000–2020: Potapov et al. 2022, UMD GLAD Global Land Cover and Land Use Change, CC BY 4.0. Images: contains modified Copernicus Sentinel data. How it's measured
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Frequently asked
Questions about Ajax
What is the air quality (AQI) in Ajax right now?
The latest reading for Ajax shows an AQI of 14 (Good), measured Nov 11, 12:00 local time by the Pickering ground monitoring station, 3.3 km away, via OpenAQ. The main pollutant is PM2.5. Air quality is satisfactory for everyone.
Is it safe to exercise outside in Ajax today?
At AQI 14 (Good): a good day to be active outside. Windows: open them to air the house. Masks: not needed. The reading changes through the day, so check again before a long run or ride.
What has the air quality in Ajax been like this week?
Over the last 7 days, the CAMS air-quality model put Ajax's daily AQI at 29 on average, from 9 on Nov 9 to an hourly peak of 56 on Nov 4. No day averaged above 100, the level where the air turns unhealthy for sensitive groups.
Is Ajax's AQI the same as Canada's AQHI?
No. Airleaf shows the US EPA Air Quality Index (AQI), the scale used by IQAir and most air-quality apps. Canada's Air Quality Health Index (AQHI), from Environment and Climate Change Canada, runs from 1 to 10 and above: 1–3 low risk, 4–6 moderate, 7–10 high and over 10 very high. It combines ozone, nitrogen dioxide and fine particles into one health-risk number, so it isn't a converted AQI, and the two can move differently, especially in wildfire smoke.
How much forest has the area around Ajax lost since 2001?
Since 2001, the area within 10 km of Ajax has lost about 154 hectares of forest (about 220 football pitches): 2.9% of the forest it had in 2000. Most of it (85%) was deforestation, forest cleared for good, mainly for towns and roads. Comparing satellite maps from 2000 and 2020, the forest around Ajax grew from about 7,250 hectares to 7,560 hectares, a net gain of about 304 hectares (+4.2%). New forest grew on about 522 hectares, while 218 hectares were lost.
What is the tree count in Ajax?
Ajax has an estimated 73,513 trees across the 12.57 km² measured — 23.4% tree cover, 7 percentage points short of the 30% tree-cover target set for this area.
How many more trees does Ajax need?
Ajax needs roughly 20,735 more trees to close a 7-point shortfall against its 30% tree-cover target — about 456.2 t of extra CO₂ absorbed per year once grown.
How are Ajax's air quality and tree cover measured?
Air quality is measured by ground monitoring stations near Ajax, via OpenAQ; the 7-day trend is the Open-Meteo / CAMS model's estimate. Tree cover is measured from Sentinel-2 L2A (ESA Copernicus) via Earth Search satellite imagery at 10 m detail across a 2 km radius around Ajax; the tree count is an estimate derived from that cover.
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