Air quality comparison · North Korea, 148 km apart
Hamhŭng vs Sunch’ŏn Air quality index (AQI) today
Hamhŭng has cleaner air than Sunch’ŏn right now: AQI 57 (Moderate) against 156 (Unhealthy).
That puts them in different EPA bands, so the health advice differs today. Over the past 7 days, on modeled daily averages, Hamhŭng averaged AQI 40 against 69, and it was the cleaner of the two on 7 of those days. Hamhŭng has lost more forest since 2001. Sunch’ŏn has more tree cover.
Updated . Lower is better on the US EPA index: 0–50 is Good, above 300 is Hazardous. Measured by Airleaf.
Hamhŭng57Sunch’ŏn156
Head to head
Hamhŭng vs Sunch’ŏn at a glance
Hamhŭng is ahead on 4 of 6 measures, and Sunch’ŏn on 2. The better figure in each row is marked.
| Hamhŭng | Sunch’ŏn | |
|---|---|---|
| Air quality nowUS AQI. Lower is better. | 57 (better) | 156 |
| PM2.5Fine particles, µg/m³. | 11.7 (better) | 69.4 |
| Past week's averageUS AQI, 7 days. | 40 (better) | 69 |
| Forest lost since 2001Within 10 km of the center. | 12 ha | 4 ha (better) |
| Tree coverWithin 2 km of the center. | 13.2% | 18.6% (better) |
| Trees still neededTo reach a healthy canopy. | 50.1K (better) | 59.6K |
Air quality today
What is the air like in Hamhŭng and Sunch’ŏn right now?
Hamhŭng has cleaner air than Sunch’ŏn right now: AQI 57 (Moderate) against 156 (Unhealthy). PM2.5 is setting the index in both.
Sunch’ŏn's PM2.5 is about 4.6× the WHO's 24-hour guideline of 15 µg/m³.
Both readings are model estimates, with no ground station close enough to either.
HamhŭngSunch’ŏn
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).
Hamhŭng: Estimate · model corrected with 5 station cities within 245 km, e.g. Chuncheon-si and Kaesŏng. Data: Open-Meteo / CAMS, corrected with 5 ground-station cities within 245 km, US EPA index.
Sunch’ŏn: Estimate · model corrected with 2 station cities within 165 km, e.g. Sinuiju and Dandong. Data: Open-Meteo / CAMS, corrected with 2 ground-station cities within 165 km, US EPA index.
The past week
Which had cleaner air over the past 7 days?
Over the past 7 days, on modeled daily averages, Hamhŭng averaged AQI 40 against 69, 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
- Hamhŭng7Sunch’ŏn0
- Average AQI
- Hamhŭng40Sunch’ŏn69
- Worst day, AQI
- Hamhŭng73Sunch’ŏn109
The daily numbers (7 days)
| Day | Hamhŭng | Sunch’ŏn |
|---|---|---|
| Nov 5 | 73 | 109 |
| Nov 6 | 24 | 50 |
| Nov 7 | 27 | 40 |
| Nov 8 | 25 | 42 |
| Nov 9 | 40 | 58 |
| Nov 10 | 36 | 80 |
| Nov 11 | 58 | 105 |
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 Hamhŭng and Sunch’ŏn today?
Hamhŭng (AQI 57, Moderate): Unusually sensitive people should consider limiting long outdoor exertion.
Sunch’ŏn (AQI 156, Unhealthy): Everyone should limit long outdoor exertion; sensitive groups more so.
Exercise outdoors
- Hamhŭng
- Fine for most people; unusually sensitive people should take long or hard exercise easier.
- Sunch’ŏn
- Everyone should cut down long or hard exercise; sensitive groups should avoid it.
Windows
- Hamhŭng
- Fine to open; close them if you are sensitive to pollution.
- Sunch’ŏn
- Keep them closed.
Masks
- Hamhŭng
- Not needed for most people.
- Sunch’ŏn
- Wear an N95 outdoors.
Air purifier
- Hamhŭng
- Worth running if you are sensitive.
- Sunch’ŏn
- Run one.
Against everywhere else
How do Hamhŭng and Sunch’ŏn compare with the rest of the world?
Right now Hamhŭng's air is cleaner than 51% of the 5,420 places Airleaf tracks, and Sunch’ŏn's is cleaner than 9%. Within North Korea, that is 64% and 7% of its 29 measured places.
Cleaner air than…
- Hamhŭng
- Beats 51%
- Sunch’ŏn
- Beats 9%
More tree cover than…
- Hamhŭng
- Beats 30%
- Sunch’ŏn
- Beats 43%
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, Hamhŭng or Sunch’ŏn?
Hamhŭng has lost more: about 12 ha of forest within 10 km of its center from 2001 to 2025, against 4 ha around Sunch’ŏn. 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.
Worst year: 2004, with 10 ha lost.
Worst year: 2002, with 1 ha lost.
| Hamhŭng | Sunch’ŏn | |
|---|---|---|
| Forest lost since 2001Cleared, burned or logged. | 12 ha | 4 ha (better) |
| Share of its forestOf what it had in 2000. | 2.6% | 1.1% (better) |
| 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 | Wildfires (84%) | Logging (53%) |
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.
Hamhŭng
2017: satellite photo from August 2017 of a 5 × 5 km area in the city center.
Sunch’ŏn
2017: satellite photo from June 2017 of a 5 × 5 km area in the city center.
Trees
Which has more trees, Hamhŭng or Sunch’ŏn?
Sunch’ŏn has more tree cover: 18.6% of the land within 2 km of its center against 13.2% around Hamhŭng, or about 51,772 trees against 39,396.
The dark mark is each place's canopy target: 30% of the land, raised where air quality is poor.
| Hamhŭng | Sunch’ŏn | |
|---|---|---|
| Trees standingEstimated from the canopy area. | 39.4K | 51.8K (better) |
| Trees still neededTo reach the target. Fewer is better. | 50.1K (better) | 59.6K |
| CO₂ absorbed each yearBy the trees already standing. | 867K kg | 1.1M 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
Hamhŭng vs Sunch’ŏn: your questions answered
Is Hamhŭng cleaner than Sunch’ŏn?
On air quality, yes, right now: Hamhŭng reads AQI 57 against 156, a gap of 99 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, Hamhŭng averaged AQI 40 against 69, and it was the cleaner of the two on 7 of those days.
Is it safe to exercise outdoors in Hamhŭng and Sunch’ŏn today?
In Hamhŭng, at AQI 57: Unusually sensitive people should consider limiting long outdoor exertion. In Sunch’ŏn, at AQI 156: Everyone should limit long outdoor exertion; sensitive groups more so.
Which has lost more forest, Hamhŭng or Sunch’ŏn?
Hamhŭng has lost more: about 12 ha of forest within 10 km of its center from 2001 to 2025, against 4 ha around Sunch’ŏn. under 1 ha of that was cleared for good, for farms, mines or towns.
Which has more trees, Hamhŭng or Sunch’ŏn?
Sunch’ŏn has more tree cover: 18.6% of the land within 2 km of its center against 13.2% around Hamhŭng, or about 51,772 trees against 39,396. Both figures describe the same-sized circle of ground around each center, not the whole municipality.
How many more trees do Hamhŭng and Sunch’ŏn need?
Hamhŭng needs about 50,140 more to reach its canopy target of 30%, and Sunch’ŏn about 59,566 to reach 40%. The target starts at 30% of the land and rises where air quality is poor.
Are Hamhŭng and Sunch’ŏn 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. Both readings are model estimates, with no ground station close enough to either. Nothing is adjusted for population, city limits or climate.
How often does the Hamhŭng vs Sunch’ŏn 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 3, 2026 and Sep 18, 2026), and the forest figures are published yearly.
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