City report · Semnan, Iran
Semnan Air quality today
Air quality in Semnan currently reads AQI 52 (Moderate): Unusually sensitive people should consider limiting long outdoor exertion.
Air quality right now
AQI 52
Moderate
- PM2.5, fine particles (µg/m³)
- 11.6
- tree cover
- 2.8%
- trees in this area
- 8.8K
- more trees needed
- 85.5K
Measured across a 2 km radius around Semnan, Semnan Province, Iran (12.57 km²), from a satellite image of Sep 25, 2026. Lower AQI is better: 0–50 is Good, above 300 is Hazardous.
Semnan · AQI 52 (Moderate)
Semnan's tree count comes to 8,796 trees across 12.57 km², 27 points below the 30% tree-cover level considered healthy for this area, so roughly 85,451 more trees would close the gap.
Air quality detail
Air quality in Semnan today: AQI 52, Moderate
Main pollutant: PM2.5 · Observed Nov 10, 20:30 local time via Open-Meteo / CAMS, US EPA index. Values in µg/m³.
Model estimate · no ground station nearby
Health signal
Unusually sensitive people should consider limiting long outdoor exertion.
PM2.5
11.6
PM10
16.3
NO₂
33.5
O₃
28.0
SO₂
3.5
CO
443.0
- Outdoor exercise
- Fine for most people; unusually sensitive people should take long or hard exercise easier
- Windows
- Fine to open; close them if you are sensitive to pollution
- Mask
- Not needed for most people
- Air purifier
- Worth running if you are sensitive
Over the last 7 days, the CAMS air-quality model put Semnan's daily AQI at 43 on average, from 14 on Nov 10 to an hourly peak of 83 on Nov 4.
Where Semnan stands: the most polluted cities in the world right now · the cleanest
Tree cover detail
Tree cover in Semnan: Critically low
2.8% tree cover against a 30% healthy-neighborhood target, across 12.57 km².
Trees in this area
8,796
Target trees
94,247
More trees needed
85,451
CO₂ if planted / yr
1,880 t
Deforestation · 2001–2025
How much forest has Semnan lost?
There was almost no forest around Semnan in 2000, so there has been almost nothing to lose since. Only fairly dense woodland counts as forest in these maps, so scattered street and garden trees don't show up here.
2017: satellite photo from July 2017 of a 5 × 5 km area in the city center.
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. Images: contains modified Copernicus Sentinel data. How it's measured
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Frequently asked
Questions about Semnan
What is the air quality (AQI) in Semnan right now?
The latest reading for Semnan shows an AQI of 52 (Moderate), observed Nov 10, 20:30 local time via Open-Meteo / CAMS, US EPA index. The main pollutant is PM2.5. Unusually sensitive people should consider limiting long outdoor exertion.
Is it safe to exercise outside in Semnan today?
At AQI 52 (Moderate): fine for most people; unusually sensitive people should take long or hard exercise easier. Windows: fine to open; close them if you are sensitive to pollution. Masks: not needed for most people. The reading changes through the day, so check again before a long run or ride.
What has the air quality in Semnan been like this week?
Over the last 7 days, the CAMS air-quality model put Semnan's daily AQI at 43 on average, from 14 on Nov 10 to an hourly peak of 83 on Nov 4. No day averaged above 100, the level where the air turns unhealthy for sensitive groups.
How much forest has the area around Semnan lost since 2001?
There was almost no forest around Semnan in 2000, so there has been almost nothing to lose since. Only fairly dense woodland counts as forest in these maps, so scattered street and garden trees don't show up here.
What is the tree count in Semnan?
Semnan has an estimated 8,796 trees across the 12.57 km² measured — 2.8% tree cover, 27 percentage points short of the 30% tree-cover target set for this area.
How many more trees does Semnan need?
Semnan needs roughly 85,451 more trees to close a 27-point shortfall against its 30% tree-cover target — about 1,880 t of extra CO₂ absorbed per year once grown.
How are Semnan'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 Semnan; the tree count is an estimate derived from that cover.
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