City report · Aland Islands
Mariehamn Air quality today
Air quality in Mariehamn currently reads AQI 33 (Good): Air quality is satisfactory for everyone.
AQI 33
Air quality right now
Good
- PM2.5, fine particles (µg/m³)
- 5.8
- tree cover
- 58.2%
- trees in this area
- 114K
- more trees needed
- 0
Measured across a 2 km radius around Mariehamn, Åland (12.57 km²), from a satellite image of Sep 14, 2026. Lower AQI is better: 0–50 is Good, above 300 is Hazardous.
Mariehamn · AQI 33 (Good)
Mariehamn's tree count comes to 113,727 trees across 7.82 km² of land, already at or above the 30% tree-cover level considered healthy for this area.
Air quality detail
Air quality in Mariehamn today: AQI 33, Good
Main pollutant: PM2.5 · Observed Nov 10, 16:00 local time via Open-Meteo / CAMS, corrected with 4 ground-station cities within 145 km, US EPA index. Values in µg/m³.
Estimate · model corrected with 4 station cities within 145 km, e.g. Uppsala and Sollentuna
Health signal
Air quality is satisfactory for everyone.
PM2.5
5.8
PM10
7.0
NO₂
3.1
O₃
64.0
SO₂
0.2
CO
178.0
- 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 Mariehamn's daily AQI at 15 on average, from 8 on Nov 4 to an hourly peak of 42 on Nov 10.
Where Mariehamn stands: the most polluted cities in the world right now · the cleanest
Tree cover detail
Tree cover in Mariehamn: Healthy tree cover
58.2% tree cover against a 30% healthy-neighborhood target, across 7.82 km² of land.
Trees in this area
113,727
Target trees
113,727
More trees needed
0
CO₂ if planted / yr
0 kg
Deforestation · 2001–2025
How much forest has Mariehamn lost?
Since 2001, the area within 10 km of Mariehamn has lost about 3,340 hectares of forest (about 4,700 football pitches): 27% of the forest it had in 2000. Most of it was lost to logging, so much of it can grow back. About 243 hectares (7.3%) was deforestation: forest cleared for good for farms, mines or towns.
2017: satellite photo from August 2017 of a 5 × 5 km area about 7 km northwest of the city center.
- Forest lost since 2001
- 3,340 haabout 4,700 football pitches
- Share of its forest
- 27%of what there was in 2000
- Cleared for good
- 243 hadeforestation: turned into farms, mines or towns
Forest loss has stayed about the same: about 172 hectares a year in 2021–2025, against 206 hectares a year in 2016–2020. The worst year was 2019, when about 493 hectares of forest were lost.
Mariehamn's full deforestation reportHectares of forest lost each year
Show the figures as a table
| Year | Cleared for good | Can grow back | Total |
|---|---|---|---|
| 2001 | 10 ha | 55 ha | 64 ha |
| 2002 | 7 ha | 46 ha | 53 ha |
| 2003 | 8 ha | 46 ha | 54 ha |
| 2004 | 7 ha | 159 ha | 166 ha |
| 2005 | 20 ha | 109 ha | 129 ha |
| 2006 | under 1 ha | under 1 ha | under 1 ha |
| 2007 | under 1 ha | 46 ha | 46 ha |
| 2008 | 20 ha | 232 ha | 252 ha |
| 2009 | 5 ha | 88 ha | 92 ha |
| 2010 | 20 ha | 71 ha | 91 ha |
| 2011 | 13 ha | 71 ha | 84 ha |
| 2012 | 17 ha | 105 ha | 122 ha |
| 2013 | 9 ha | 80 ha | 89 ha |
| 2014 | 5 ha | 76 ha | 81 ha |
| 2015 | 2 ha | 122 ha | 124 ha |
| 2016 | 22 ha | 89 ha | 111 ha |
| 2017 | 5 ha | 160 ha | 165 ha |
| 2018 | 12 ha | 129 ha | 141 ha |
| 2019 | 12 ha | 481 ha | 493 ha |
| 2020 | 8 ha | 111 ha | 119 ha |
| 2021 | 11 ha | 246 ha | 257 ha |
| 2022 | 11 ha | 183 ha | 194 ha |
| 2023 | 6 ha | 193 ha | 199 ha |
| 2024 | 5 ha | 109 ha | 114 ha |
| 2025 | 9 ha | 88 ha | 98 ha |
What is causing deforestation around Mariehamn?
- Loggingcan grow back93% · 3,090 ha
- Towns and roadscleared for good6.3% · 211 ha
Also: farms, pasture and plantations, wildfires, mining and energy, 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
- 11,400 ha
- Forest in 2020
- 10,300 ha
- Overall change
- −1,110 haless forest than in 2000
Comparing satellite maps from 2000 and 2020, the forest around Mariehamn shrank from about 11,400 hectares to 10,300 hectares, a net loss of about 1,110 hectares (−9.7%). New forest grew on about 357 hectares, but 1,460 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 Mariehamn
What is the air quality (AQI) in Mariehamn right now?
The latest reading for Mariehamn shows an AQI of 33 (Good), observed Nov 10, 16:00 local time via Open-Meteo / CAMS, corrected with 4 ground-station cities within 145 km, US EPA index. The main pollutant is PM2.5. Air quality is satisfactory for everyone.
Is it safe to exercise outside in Mariehamn today?
At AQI 33 (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 Mariehamn been like this week?
Over the last 7 days, the CAMS air-quality model put Mariehamn's daily AQI at 15 on average, from 8 on Nov 4 to an hourly peak of 42 on Nov 10. No day averaged above 100, the level where the air turns unhealthy for sensitive groups.
How much forest has the area around Mariehamn lost since 2001?
Since 2001, the area within 10 km of Mariehamn has lost about 3,340 hectares of forest (about 4,700 football pitches): 27% of the forest it had in 2000. Most of it was lost to logging, so much of it can grow back. About 243 hectares (7.3%) was deforestation: forest cleared for good for farms, mines or towns. Forest loss has stayed about the same: about 172 hectares a year in 2021–2025, against 206 hectares a year in 2016–2020. Comparing satellite maps from 2000 and 2020, the forest around Mariehamn shrank from about 11,400 hectares to 10,300 hectares, a net loss of about 1,110 hectares (−9.7%). New forest grew on about 357 hectares, but 1,460 hectares were lost.
What is the tree count in Mariehamn?
Mariehamn has an estimated 113,727 trees across the 7.82 km² of land measured — 58.2% tree cover, already past the 30% tree-cover target set for this area.
How many more trees does Mariehamn need?
Mariehamn has already reached its tree-cover target, so no additional trees are needed to close the gap.
How are Mariehamn's air quality and tree cover measured?
Air quality comes from ground monitoring stations via OpenAQ where one reports nearby, and otherwise, as here, from the Open-Meteo / CAMS model, which may differ from street-level monitors. 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 Mariehamn; the tree count is an estimate derived from that cover.
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