Air quality comparison · Algeria, 339 km apart
Blida vs Constantine Air quality index (AQI) today
Blida and Constantine are level right now: both read AQI 54 (Moderate).
Over the past 6 days, on modeled daily averages, Blida averaged AQI 39 against 42, and it was the cleaner of the two on 5 of those days. Blida has lost more forest since 2001. Blida has more tree cover.
Algeria
AQI 54
Moderate
Cleaner right now
- PM2.5
- 11.7 µg/m³
- Main pollutant
- PM2.5
- Source
- Model estimate
- Reading
- Nov 10, 20:00 local
Algeria
AQI 54
Moderate
Cleaner right now
- PM2.5
- 11.7 µg/m³
- Main pollutant
- PM2.5
- Source
- Model estimate
- Reading
- Nov 11, 06:00 local
Updated . Lower is better on the US EPA index: 0–50 is Good, above 300 is Hazardous. Measured by Airleaf.
Blida54Constantine54
Head to head
Blida vs Constantine at a glance
Blida is ahead on 3 of 6 measures, and Constantine on 1. The better figure in each row is marked.
| Blida | Constantine | |
|---|---|---|
| Air quality nowUS AQI. Lower is better. | 54 | 54 |
| PM2.5Fine particles, µg/m³. | 11.7 | 11.7 |
| Past week's averageUS AQI, 6 days. | 39 (better) | 42 |
| Forest lost since 2001Within 10 km of the center. | 1,410 ha | 170 ha (better) |
| Tree coverWithin 2 km of the center. | 27.5% (better) | 21.9% |
| Trees still neededTo reach a healthy canopy. | 7.9K (better) | 25.4K |
Air quality today
What is the air like in Blida and Constantine right now?
Blida and Constantine are level right now: both read AQI 54 (Moderate). PM2.5 is setting the index in both.
Both readings are model estimates, with no ground station close enough to either.
BlidaConstantine
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).
Blida: Model estimate · no ground station nearby. Data: Open-Meteo / CAMS, US EPA index.
Constantine: Model estimate · no ground station nearby. Data: Open-Meteo / CAMS, US EPA index.
The past week
Which had cleaner air over the past 6 days?
Over the past 6 days, on modeled daily averages, Blida averaged AQI 39 against 42, and it was the cleaner of the two on 5 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
- Blida5Constantine1
- Average AQI
- Blida39Constantine42
- Worst day, AQI
- Blida44Constantine49
The daily numbers (6 days)
| Day | Blida | Constantine |
|---|---|---|
| Nov 5 | 36 | 40 |
| Nov 6 | 35 | 42 |
| Nov 7 | 41 | 40 |
| Nov 8 | 37 | 43 |
| Nov 9 | 39 | 40 |
| Nov 10 | 44 | 49 |
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 Blida and Constantine today?
Unusually sensitive people should consider limiting long outdoor exertion. Both are in the same EPA band today (Moderate), so the advice is the same.
Exercise outdoors
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.
Air purifier
Worth running if you are sensitive.
Against everywhere else
How do Blida and Constantine compare with the rest of the world?
Right now Blida's air is cleaner than 56% of the 5,420 places Airleaf tracks, and Constantine's is cleaner than 56%. Within Algeria, that is 23% and 23% of its 40 measured places.
Cleaner air than…
- Blida
- Beats 56%
- Constantine
- Beats 56%
More tree cover than…
- Blida
- Beats 63%
- Constantine
- Beats 51%
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, Blida or Constantine?
Blida has lost more: about 1,410 ha of forest within 10 km of its center from 2001 to 2025, against 170 ha around Constantine. 190 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: 2025, with 371 ha lost.
Worst year: 2009, with 38 ha lost.
| Blida | Constantine | |
|---|---|---|
| Forest lost since 2001Cleared, burned or logged. | 1,410 ha | 170 ha (better) |
| Share of its forestOf what it had in 2000. | 12% (better) | 22% |
| Cleared for goodTurned into farms, mines or towns. | 190 ha | 22 ha (better) |
| Recent trend2021–2025 against the five years before. | Speeding up | Too little to call |
| Main known cause | Wildfires (85%) | Wildfires (73%) |
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.
Blida
2017: satellite photo from September 2017 of a 5 × 5 km area about 3 km southeast of the city center.
Constantine
2017: satellite photo from July 2017 of a 5 × 5 km area in the city center.
Trees
Which has more trees, Blida or Constantine?
Blida has more tree cover: 27.5% of the land within 2 km of its center against 21.9% around Constantine, or about 86,394 trees against 68,801.
The dark mark is each place's canopy target: 30% of the land, raised where air quality is poor.
| Blida | Constantine | |
|---|---|---|
| Trees standingEstimated from the canopy area. | 86.4K (better) | 68.8K |
| Trees still neededTo reach the target. Fewer is better. | 7.9K (better) | 25.4K |
| CO₂ absorbed each yearBy the trees already standing. | 1.9M kg (better) | 1.5M 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
Blida vs Constantine: your questions answered
Is Blida cleaner than Constantine?
On air quality they are level right now: both read 54 on the US EPA index. Air quality changes through the day, so this can separate within hours. Over the past 6 days, on modeled daily averages, Blida averaged AQI 39 against 42, and it was the cleaner of the two on 5 of those days.
Is it safe to exercise outdoors in Blida and Constantine today?
The advice is the same for both today. Unusually sensitive people should consider limiting long outdoor exertion. Blida reads AQI 54 and Constantine reads AQI 54.
Which has lost more forest, Blida or Constantine?
Blida has lost more: about 1,410 ha of forest within 10 km of its center from 2001 to 2025, against 170 ha around Constantine. 190 ha of that was cleared for good, for farms, mines or towns.
Which has more trees, Blida or Constantine?
Blida has more tree cover: 27.5% of the land within 2 km of its center against 21.9% around Constantine, or about 86,394 trees against 68,801. Both figures describe the same-sized circle of ground around each center, not the whole municipality.
How many more trees do Blida and Constantine need?
Blida needs about 7,854 more to reach its canopy target of 30%, and Constantine about 25,447 to reach 30%. The target starts at 30% of the land and rises where air quality is poor.
Are Blida and Constantine 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 Blida vs Constantine 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 9, 2026), and the forest figures are published yearly.
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