Air quality comparison · Romania, 486 km apart
Cluj-Napoca vs Constanţa Air quality index (AQI) today
Cluj-Napoca has cleaner air than Constanţa right now: AQI 55 (Moderate) against 107 (Unhealthy for sensitive groups).
That puts them in different EPA bands, so the health advice differs today. But over the past 6 days, on modeled daily averages, Constanţa averaged AQI 37 against 74, and it was the cleaner of the two on 6 of those days. Cluj-Napoca has lost more forest since 2001. Cluj-Napoca has more tree cover.
Romania
AQI 55
Moderate
Cleaner right now
- PM2.5
- 11.4 µg/m³
- Main pollutant
- PM2.5
- Source
- Ground station
- Reading
- Nov 11, 20:00 local
Romania
AQI 107
Unhealthy for sensitive groups
Cleaner right now
- PM2.5
- 37.9 µg/m³2.5× WHO guideline
- Main pollutant
- PM2.5
- Source
- Ground station
- Reading
- Nov 11, 21:00 local
Updated . Lower is better on the US EPA index: 0–50 is Good, above 300 is Hazardous. Measured by Airleaf.
Cluj-Napoca55Constanţa107
Head to head
Cluj-Napoca vs Constanţa at a glance
Cluj-Napoca is ahead on 4 of 6 measures, and Constanţa on 2. The better figure in each row is marked.
| Cluj-Napoca | Constanţa | |
|---|---|---|
| Air quality nowUS AQI. Lower is better. | 55 (better) | 107 |
| PM2.5Fine particles, µg/m³. | 11.4 (better) | 37.9 |
| Past week's averageUS AQI, 6 days. | 74 | 37 (better) |
| Forest lost since 2001Within 10 km of the center. | 240 ha | 1 ha (better) |
| Tree coverWithin 2 km of the center. | 26.5% (better) | 19.3% |
| Trees still neededTo reach a healthy canopy. | 11.0K (better) | 48.3K |
Air quality today
What is the air like in Cluj-Napoca and Constanţa right now?
Cluj-Napoca has cleaner air than Constanţa right now: AQI 55 (Moderate) against 107 (Unhealthy for sensitive groups). PM2.5 is setting the index in both.
Constanţa's PM2.5 is about 2.5× the WHO's 24-hour guideline of 15 µg/m³.
Both readings come from nearby ground stations.
Cluj-NapocaConstanţa
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).
The past week
Which had cleaner air over the past 6 days?
But over the past 6 days, on modeled daily averages, Constanţa averaged AQI 37 against 74, and it was the cleaner of the two on 6 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
- Cluj-Napoca0Constanţa6
- Average AQI
- Cluj-Napoca74Constanţa37
- Worst day, AQI
- Cluj-Napoca95Constanţa57
The daily numbers (6 days)
| Day | Cluj-Napoca | Constanţa |
|---|---|---|
| Nov 5 | 69 | 27 |
| Nov 6 | 58 | 57 |
| Nov 7 | 63 | 26 |
| Nov 8 | 73 | 33 |
| Nov 9 | 86 | 37 |
| Nov 10 | 95 | 40 |
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 Cluj-Napoca and Constanţa today?
Cluj-Napoca (AQI 55, Moderate): Unusually sensitive people should consider limiting long outdoor exertion.
Constanţa (AQI 107, Unhealthy for sensitive groups): Sensitive groups should limit long or intense outdoor activity.
Exercise outdoors
- Cluj-Napoca
- Fine for most people; unusually sensitive people should take long or hard exercise easier.
- Constanţa
- Children, older adults and people with asthma or heart disease should cut down long or hard exercise.
Windows
- Cluj-Napoca
- Fine to open; close them if you are sensitive to pollution.
- Constanţa
- Close them to keep the outside air out.
Masks
- Cluj-Napoca
- Not needed for most people.
- Constanţa
- Sensitive groups: an N95 outdoors.
Air purifier
- Cluj-Napoca
- Worth running if you are sensitive.
- Constanţa
- Run one, especially in bedrooms.
Against everywhere else
How do Cluj-Napoca and Constanţa compare with the rest of the world?
Right now Cluj-Napoca's air is cleaner than 54% of the 5,420 places Airleaf tracks, and Constanţa's is cleaner than 20%. Within Romania, that is 95% and 26% of its 20 measured places.
Cleaner air than…
- Cluj-Napoca
- Beats 54%
- Constanţa
- Beats 20%
More tree cover than…
- Cluj-Napoca
- Beats 61%
- Constanţa
- Beats 45%
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, Cluj-Napoca or Constanţa?
Cluj-Napoca has lost more: about 240 ha of forest within 10 km of its center from 2001 to 2025, against 1 ha around Constanţa. 93 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: 2007, with 20 ha lost.
Worst year: 2004, with under 1 ha lost.
| Cluj-Napoca | Constanţa | |
|---|---|---|
| Forest lost since 2001Cleared, burned or logged. | 240 ha | 1 ha (better) |
| Cleared for goodTurned into farms, mines or towns. | 93 ha | under 1 ha (better) |
| Recent trend2021–2025 against the five years before. | Too little to call | Too little to call |
| Main known cause | Logging (58%) | Towns and roads (27%) |
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.
Cluj-Napoca
2017: satellite photo from August 2017 of a 5 × 5 km area in the city center.
Constanţa
2017: satellite photo from August 2017 of a 5 × 5 km area in the city center.
Trees
Which has more trees, Cluj-Napoca or Constanţa?
Cluj-Napoca has more tree cover: 26.5% of the land within 2 km of its center against 19.3% around Constanţa, or about 83,169 trees against 59,359.
The dark mark is each place's canopy target: 30% of the land, raised where air quality is poor.
| Cluj-Napoca | Constanţa | |
|---|---|---|
| Trees standingEstimated from the canopy area. | 83.2K (better) | 59.4K |
| Trees still neededTo reach the target. Fewer is better. | 11.0K (better) | 48.3K |
| CO₂ absorbed each yearBy the trees already standing. | 1.8M kg (better) | 1.3M kg |
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
Cluj-Napoca vs Constanţa: your questions answered
Is Cluj-Napoca cleaner than Constanţa?
On air quality, yes, right now: Cluj-Napoca reads AQI 55 against 107, a gap of 52 points on the US EPA index. This is a live reading rather than an annual average, so it can reverse within a day. But over the past 6 days, on modeled daily averages, Constanţa averaged AQI 37 against 74, and it was the cleaner of the two on 6 of those days.
Is it safe to exercise outdoors in Cluj-Napoca and Constanţa today?
In Cluj-Napoca, at AQI 55: Unusually sensitive people should consider limiting long outdoor exertion. In Constanţa, at AQI 107: Sensitive groups should limit long or intense outdoor activity.
Which has lost more forest, Cluj-Napoca or Constanţa?
Cluj-Napoca has lost more: about 240 ha of forest within 10 km of its center from 2001 to 2025, against 1 ha around Constanţa. 93 ha of that was cleared for good, for farms, mines or towns.
Which has more trees, Cluj-Napoca or Constanţa?
Cluj-Napoca has more tree cover: 26.5% of the land within 2 km of its center against 19.3% around Constanţa, or about 83,169 trees against 59,359. Both figures describe the same-sized circle of ground around each center, not the whole municipality.
How many more trees do Cluj-Napoca and Constanţa need?
Cluj-Napoca needs about 10,985 more to reach its canopy target of 30%, and Constanţa about 48,287 to reach 35%. The target starts at 30% of the land and rises where air quality is poor.
Are Cluj-Napoca and Constanţa 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 come from nearby ground stations. Nothing is adjusted for population, city limits or climate.
How often does the Cluj-Napoca vs Constanţa 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 19, 2026 and Sep 18, 2026), and the forest figures are published yearly.
Keep going
Compare them with somewhere else
Build your own
Compare Cluj-Napoca with somewhere else
This place
Cluj-Napoca