Air quality comparison · Mongolia, 189 km apart
Darhan vs Ulan Bator Air quality index (AQI) today
Darhan has cleaner air than Ulan Bator right now: AQI 23 (Good) against 153 (Unhealthy).
That puts them in different EPA bands, so the health advice differs today. Over the past 7 days, on modeled daily averages, Darhan averaged AQI 24 against 133, and it was the cleaner of the two on 7 of those days. Ulan Bator has lost more forest since 2001. Ulan Bator has more tree cover.
Mongolia
AQI 23
Good
Cleaner right now
- PM2.5
- 3.6 µg/m³
- Main pollutant
- PM2.5
- Source
- Model estimate
- Reading
- Nov 12, 11:00 local
Mongolia
AQI 153
Unhealthy
Cleaner right now
- PM2.5
- 57.9 µg/m³3.9× WHO guideline
- Main pollutant
- PM2.5
- Source
- Ground station
- Reading
- Nov 13, 00:00 local
Updated . Lower is better on the US EPA index: 0–50 is Good, above 300 is Hazardous. Measured by Airleaf.
Darhan23Ulan Bator153
Head to head
Darhan vs Ulan Bator at a glance
Darhan is ahead on 5 of 6 measures, and Ulan Bator on 1. The better figure in each row is marked.
| Darhan | Ulan Bator | |
|---|---|---|
| Air quality nowUS AQI. Lower is better. | 23 (better) | 153 |
| PM2.5Fine particles, µg/m³. | 3.6 (better) | 57.9 |
| Past week's averageUS AQI, 7 days. | 24 (better) | 133 |
| Forest lost since 2001Within 10 km of the center. | under 1 ha (better) | 559 ha |
| Tree coverWithin 2 km of the center. | 1.1% | 3.7% (better) |
| Trees still neededTo reach a healthy canopy. | 90.8K (better) | 114K |
Air quality today
What is the air like in Darhan and Ulan Bator right now?
Darhan has cleaner air than Ulan Bator right now: AQI 23 (Good) against 153 (Unhealthy). PM2.5 is setting the index in both.
Ulan Bator's PM2.5 is about 3.9× the WHO's 24-hour guideline of 15 µg/m³.
Ulan Bator is read from a nearby ground station and Darhan is a model estimate, so the two are not quite like for like.
DarhanUlan Bator
Concentrations at the same moment as the index above, for the pollutants both places report. Lower is better. The dark marks on the PM2.5 and PM10 rows show the WHO's 24-hour guidelines (15 and 45 µg/m³).
Darhan: Model estimate · no ground station nearby. Data: Open-Meteo / CAMS, US EPA index.
Ulan Bator: Ground station · Bumbugur, 1.8 km away. Data: OpenAQ · AirGradient, Andy.
The past week
Which had cleaner air over the past 7 days?
Over the past 7 days, on modeled daily averages, Darhan averaged AQI 24 against 133, and it was the cleaner of the two on 7 of those days. A single reading can catch a city on a bad afternoon; the week says whether it was the weather or the place.
- Cleaner days
- Darhan7Ulan Bator0
- Average AQI
- Darhan24Ulan Bator133
- Worst day, AQI
- Darhan44Ulan Bator147
The daily numbers (7 days)
| Day | Darhan | Ulan Bator |
|---|---|---|
| Nov 6 | 43 | 137 |
| Nov 7 | 44 | 103 |
| Nov 8 | 27 | 141 |
| Nov 9 | 13 | 114 |
| Nov 10 | 10 | 145 |
| Nov 11 | 23 | 141 |
| Nov 12 | 11 | 147 |
Daily averages from the CAMS atmospheric model for both places, so the week compares like with like. They can differ from today's reading at the top of the page wherever that comes from a ground station.
What it means today
Is it safe to go outside in Darhan and Ulan Bator today?
Darhan (AQI 23, Good): Air quality is satisfactory for everyone.
Ulan Bator (AQI 153, Unhealthy): Everyone should limit long outdoor exertion; sensitive groups more so.
Exercise outdoors
- Darhan
- A good day to be active outside.
- Ulan Bator
- Everyone should cut down long or hard exercise; sensitive groups should avoid it.
Windows
- Darhan
- Open them to air the house.
- Ulan Bator
- Keep them closed.
Masks
- Darhan
- Not needed.
- Ulan Bator
- Wear an N95 outdoors.
Air purifier
- Darhan
- Not needed.
- Ulan Bator
- Run one.
Against everywhere else
How do Darhan and Ulan Bator compare with the rest of the world?
Right now Darhan's air is cleaner than 85% of the 5,420 places Airleaf tracks, and Ulan Bator's is cleaner than 11%. Within Mongolia, that is 50% and 0% of its 5 measured places.
Cleaner air than…
- Darhan
- Beats 85%
- Ulan Bator
- Beats 11%
More tree cover than…
- Darhan
- Beats 2%
- Ulan Bator
- Beats 7%
Includes model estimates as well as station readings, so it can differ from our most polluted and cleanest air rankings, which use station readings only.
Deforestation · 2001–2025
Which has lost more forest, Darhan or Ulan Bator?
Ulan Bator has lost more: about 559 ha of forest within 10 km of its center from 2001 to 2025, against under 1 ha around Darhan. under 1 ha of that was cleared for good, for farms, mines or towns.
Measured within 10 km of each center, from the yearly satellite maps of forest loss: a wider circle than the one for tree cover, because forest is usually lost at a city's edges.
No forest lost in any year.
Worst year: 2008, with 177 ha lost.
| Darhan | Ulan Bator | |
|---|---|---|
| Forest lost since 2001Cleared, burned or logged. | under 1 ha (better) | 559 ha |
| Cleared for goodTurned into farms, mines or towns. | under 1 ha | under 1 ha |
| Recent trend2021–2025 against the five years before. | Too little to call | Too little to call |
| Main known cause | Not classified | Wildfires (97%) |
Satellite timelapses
Watch both change, year by year
A clear satellite photo a year of the land around each city. Press play, turn on the forest cleared since the first year, or drag the before and after.
Darhan
2017: satellite photo from September 2017 of a 5 × 5 km area in the city center.
Ulan Bator
2017: satellite photo from June 2017 of a 5 × 5 km area in the city center.
Trees
Which has more trees, Darhan or Ulan Bator?
Ulan Bator has more tree cover: 3.7% of the land within 2 km of its center against 1.1% around Darhan, or about 11,624 trees against 3,456.
The dark mark is each place's canopy target: 30% of the land, raised where air quality is poor.
| Darhan | Ulan Bator | |
|---|---|---|
| Trees standingEstimated from the canopy area. | 3.5K | 11.6K (better) |
| Trees still neededTo reach the target. Fewer is better. | 90.8K (better) | 114K |
| CO₂ absorbed each yearBy the trees already standing. | 76.0K kg | 256K kg (better) |
Tree cover on the satellite image
The same 2 km radius around each center, with the tree cover the satellite found marked on it.
Reading these numbers
How this comparison is made
Air quality index
The US EPA index, computed from current pollutant concentrations: ground stations where a place has them nearby, and the CAMS atmospheric model everywhere else. It moves hour to hour, so it is a snapshot rather than a verdict on either place. The guideline marks are from the WHO's 2021 air quality guidelines.
Trees and forest
Tree cover is the share of ground under canopy within 2 km of each center, read from Sentinel-2 satellite imagery at 10 m detail. It measures that circle, not the whole municipality, which is what makes the two comparable. Forest loss comes from the University of Maryland's Global Forest Change maps.
More on the method on the About Airleaf page.
Frequently asked
Darhan vs Ulan Bator: your questions answered
Is Darhan cleaner than Ulan Bator?
On air quality, yes, right now: Darhan reads AQI 23 against 153, a gap of 130 points on the US EPA index. This is a live reading rather than an annual average, so it can reverse within a day. Over the past 7 days, on modeled daily averages, Darhan averaged AQI 24 against 133, and it was the cleaner of the two on 7 of those days.
Is it safe to exercise outdoors in Darhan and Ulan Bator today?
In Darhan, at AQI 23: Air quality is satisfactory for everyone. In Ulan Bator, at AQI 153: Everyone should limit long outdoor exertion; sensitive groups more so.
Which has lost more forest, Darhan or Ulan Bator?
Ulan Bator has lost more: about 559 ha of forest within 10 km of its center from 2001 to 2025, against under 1 ha around Darhan. under 1 ha of that was cleared for good, for farms, mines or towns.
Which has more trees, Darhan or Ulan Bator?
Ulan Bator has more tree cover: 3.7% of the land within 2 km of its center against 1.1% around Darhan, or about 11,624 trees against 3,456. Both figures describe the same-sized circle of ground around each center, not the whole municipality.
How many more trees do Darhan and Ulan Bator need?
Darhan needs about 90,792 more to reach its canopy target of 30%, and Ulan Bator about 114,040 to reach 40%. The target starts at 30% of the land and rises where air quality is poor.
Are Darhan and Ulan Bator measured the same way?
The method is the same: the US EPA index for air, and Sentinel-2 satellite imagery at 10 m detail over an identical radius for trees. Ulan Bator is read from a nearby ground station and Darhan is a model estimate, so the two are not quite like for like. Nothing is adjusted for population, city limits or climate.
How often does the Darhan vs Ulan Bator comparison update?
The air readings refresh about once an hour, and each reading's local time is shown at the top of the page. Tree cover comes from the latest clear satellite image of each area (Sep 15, 2026 and Sep 15, 2026), and the forest figures are published yearly.
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