City report · Oregon, United States
Gresham Air quality today
Air quality in Gresham currently reads AQI 9 (Good): Air quality is satisfactory for everyone.
Air quality right now
AQI 9
Good
- PM2.5, fine particles (µg/m³)
- 1.7
- tree cover
- 47.5%
- trees in this area
- 149K
- more trees needed
- 0
Measured across a 1.2 mi (2 km) radius around City Central, Gresham, OR, USA (4.9 sq mi), from a satellite image of Sep 8, 2026. Lower AQI is better: 0–50 is Good, above 300 is Hazardous.
Gresham · AQI 9 (Good)
Gresham's tree count comes to 149,226 trees across 4.9 sq mi (12.57 km²), already at or above the 30% tree-cover level considered healthy for this area.
Air quality detail
Air quality in Gresham today: AQI 9, Good
Main pollutant: PM2.5 · Observed Nov 11, 07:00 local time via OpenAQ ground stations, US EPA index. Values in µg/m³.
Ground station · Damascus, 5.5 mi (8.8 km) away
Health signal
Air quality is satisfactory for everyone.
PM2.5
1.7
PM10
—
NO₂
—
O₃
—
SO₂
—
CO
—
Data: OpenAQ · AirGradient
- 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 Gresham's daily AQI at 39 on average, from 12 on Nov 10 to an hourly peak of 79 on Nov 5.
Where Gresham stands: the most polluted cities in the world right now · the cleanest
Tree cover detail
Tree cover in Gresham: Healthy tree cover
47.5% tree cover against a 30% healthy-neighborhood target, across 4.9 sq mi (12.57 km²).
Trees in this area
149,226
Target trees
149,226
More trees needed
0
CO₂ if planted / yr
0 kg
Deforestation · 2001–2025
How much forest has Gresham lost?
Since 2001, the area within 10 km of Gresham has lost about 1,310 acres (528 hectares) of forest (about 990 football fields): 6.3% of the forest it had in 2000. Most of it (83%) was deforestation, forest cleared for good, mainly for towns and roads.
2017: satellite photo from August 2017 of a 5 × 5 km area about 6 km southwest of the city center.
- Forest lost since 2001
- 1,310 acres (528 ha)about 990 football fields
- Share of its forest
- 6.3%of what there was in 2000
- Cleared for good
- 1,090 acres (439 ha)deforestation: turned into farms, mines or towns
The worst year was 2005, when about 219 acres (89 hectares) of forest were lost.
Acres of forest lost each year
Show the figures as a table
| Year | Cleared for good | Can grow back | Total |
|---|---|---|---|
| 2001 | 17 acres (7 ha) | under 1 ha | 19 acres (8 ha) |
| 2002 | 33 acres (13 ha) | 4 acres (2 ha) | 37 acres (15 ha) |
| 2003 | 53 acres (21 ha) | 12 acres (5 ha) | 65 acres (26 ha) |
| 2004 | 71 acres (29 ha) | 9 acres (4 ha) | 79 acres (32 ha) |
| 2005 | 150 acres (61 ha) | 69 acres (28 ha) | 219 acres (89 ha) |
| 2006 | 50 acres (20 ha) | 14 acres (6 ha) | 64 acres (26 ha) |
| 2007 | 46 acres (19 ha) | 4 acres (2 ha) | 50 acres (20 ha) |
| 2008 | 34 acres (14 ha) | 4 acres (2 ha) | 38 acres (15 ha) |
| 2009 | 33 acres (13 ha) | 16 acres (6 ha) | 49 acres (20 ha) |
| 2010 | 3 acres (1 ha) | under 1 ha | 4 acres (2 ha) |
| 2011 | 23 acres (9 ha) | 6 acres (2 ha) | 28 acres (11 ha) |
| 2012 | 16 acres (6 ha) | under 1 ha | 18 acres (7 ha) |
| 2013 | 10 acres (4 ha) | 4 acres (2 ha) | 14 acres (6 ha) |
| 2014 | 33 acres (13 ha) | 12 acres (5 ha) | 45 acres (18 ha) |
| 2015 | 38 acres (15 ha) | 3 acres (1 ha) | 41 acres (17 ha) |
| 2016 | 43 acres (18 ha) | 3 acres (1 ha) | 46 acres (19 ha) |
| 2017 | 83 acres (34 ha) | 13 acres (5 ha) | 96 acres (39 ha) |
| 2018 | 78 acres (32 ha) | 3 acres (1 ha) | 81 acres (33 ha) |
| 2019 | 35 acres (14 ha) | 5 acres (2 ha) | 41 acres (16 ha) |
| 2020 | 23 acres (9 ha) | under 1 ha | 25 acres (10 ha) |
| 2021 | 45 acres (18 ha) | 7 acres (3 ha) | 52 acres (21 ha) |
| 2022 | 62 acres (25 ha) | 3 acres (1 ha) | 65 acres (26 ha) |
| 2023 | 29 acres (12 ha) | 10 acres (4 ha) | 40 acres (16 ha) |
| 2024 | 66 acres (27 ha) | 7 acres (3 ha) | 73 acres (30 ha) |
| 2025 | 12 acres (5 ha) | 5 acres (2 ha) | 17 acres (7 ha) |
What is causing deforestation around Gresham?
- Towns and roadscleared for good66% · 860 acres (348 ha)
- Farms, pasture and plantationscleared for good17% · 226 acres (92 ha)
- Loggingcan grow back15% · 190 acres (77 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
- 36,500 acres (14,800 ha)
- Forest in 2020
- 37,600 acres (15,200 ha)
- Overall change
- +1,130 acres (456 ha)more forest than in 2000
Comparing satellite maps from 2000 and 2020, the forest around Gresham grew from about 36,500 acres (14,800 hectares) to 37,600 acres (15,200 hectares), a net gain of about 1,130 acres (456 hectares) (+3.1%). New forest grew on about 1,890 acres (766 hectares), while 764 acres (309 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
In the same region
Measured cities near Gresham
Same 2 km radius, same index — so they compare directly.
- Portland19.3 km
United States
- Tree cover
- 21%
- Air quality
- 44
- Vancouver23.8 km
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- Tree cover
- 36%
- Air quality
- 48
- Hillsboro43.6 km
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- Tree cover
- 41%
- Air quality
- 43
- Salem77.8 km
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- Tree cover
- 42%
- Air quality
- 51
- Eugene168.9 km
United States
- Tree cover
- 37%
- Air quality
- 64
- Tacoma195.1 km
United States
- Tree cover
- 19%
- Air quality
- 38
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Frequently asked
Questions about Gresham
What is the air quality (AQI) in Gresham right now?
The latest reading for Gresham shows an AQI of 9 (Good), measured Nov 11, 07:00 local time by the Damascus ground monitoring station, 5.5 mi (8.8 km) away, via OpenAQ. The main pollutant is PM2.5. Air quality is satisfactory for everyone.
Is it safe to exercise outside in Gresham today?
At AQI 9 (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 Gresham been like this week?
Over the last 7 days, the CAMS air-quality model put Gresham's daily AQI at 39 on average, from 12 on Nov 10 to an hourly peak of 79 on Nov 5. No day averaged above 100, the level where the air turns unhealthy for sensitive groups.
How much forest has the area around Gresham lost since 2001?
Since 2001, the area within 10 km of Gresham has lost about 1,310 acres (528 hectares) of forest (about 990 football fields): 6.3% of the forest it had in 2000. Most of it (83%) was deforestation, forest cleared for good, mainly for towns and roads. Comparing satellite maps from 2000 and 2020, the forest around Gresham grew from about 36,500 acres (14,800 hectares) to 37,600 acres (15,200 hectares), a net gain of about 1,130 acres (456 hectares) (+3.1%). New forest grew on about 1,890 acres (766 hectares), while 764 acres (309 hectares) were lost.
What is the tree count in Gresham?
Gresham has an estimated 149,226 trees across the 4.9 sq mi (12.57 km²) measured — 47.5% tree cover, already past the 30% tree-cover target set for this area.
How many more trees does Gresham need?
Gresham has already reached its tree-cover target, so no additional trees are needed to close the gap.
How are Gresham's air quality and tree cover measured?
Air quality is measured by ground monitoring stations near City Central, 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 1.2 mi (2 km) radius around City Central; the tree count is an estimate derived from that cover.
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