Air quality comparison · Tanzania, 431 km apart
Arusha vs Mwanza Air quality index (AQI) today
Mwanza has cleaner air than Arusha right now: AQI 21 (Good) against 90 (Moderate).
That puts them in different EPA bands, so the health advice differs today. Over the past 7 days, on modeled daily averages, Mwanza averaged AQI 34 against 42, and it was the cleaner of the two on 5 of those days. Arusha has lost more forest since 2001. Arusha has more tree cover.
Updated . Lower is better on the US EPA index: 0–50 is Good, above 300 is Hazardous. Measured by Airleaf.
Arusha90Mwanza21
Head to head
Arusha vs Mwanza at a glance
Mwanza is ahead on 4 of 6 measures, and Arusha on 2. The better figure in each row is marked.
| Arusha | Mwanza | |
|---|---|---|
| Air quality nowUS AQI. Lower is better. | 90 | 21 (better) |
| PM2.5Fine particles, µg/m³. | 25.6 | 3.2 (better) |
| Past week's averageUS AQI, 7 days. | 42 | 34 (better) |
| Forest lost since 2001Within 10 km of the center. | 771 ha | 28 ha (better) |
| Tree coverWithin 2 km of the center. | 31.4% (better) | 23.5% |
| Trees still neededTo reach a healthy canopy. | 0 (better) | 15.6K |
Air quality today
What is the air like in Arusha and Mwanza right now?
Mwanza has cleaner air than Arusha right now: AQI 21 (Good) against 90 (Moderate). PM2.5 is setting the index in both.
Arusha's PM2.5 is about 1.7× the WHO's 24-hour guideline of 15 µg/m³.
Both readings are model estimates, with no ground station close enough to either.
ArushaMwanza
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).
Arusha: Estimate · model corrected with 2 station cities within 225 km, e.g. Ongata Rongai and Ngong. Data: Open-Meteo / CAMS, corrected with 2 ground-station cities within 225 km, US EPA index.
Mwanza: Model estimate · no ground station nearby. Data: Open-Meteo / CAMS, US EPA index.
The past week
Which had cleaner air over the past 7 days?
Over the past 7 days, on modeled daily averages, Mwanza averaged AQI 34 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
- Arusha2Mwanza5
- Average AQI
- Arusha42Mwanza34
- Worst day, AQI
- Arusha50Mwanza48
The daily numbers (7 days)
| Day | Arusha | Mwanza |
|---|---|---|
| Nov 5 | 35 | 33 |
| Nov 6 | 32 | 48 |
| Nov 7 | 44 | 42 |
| Nov 8 | 46 | 48 |
| Nov 9 | 50 | 25 |
| Nov 10 | 38 | 20 |
| Nov 11 | 48 | 23 |
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 Arusha and Mwanza today?
Arusha (AQI 90, Moderate): Unusually sensitive people should consider limiting long outdoor exertion.
Mwanza (AQI 21, Good): Air quality is satisfactory for everyone.
Exercise outdoors
- Arusha
- Fine for most people; unusually sensitive people should take long or hard exercise easier.
- Mwanza
- A good day to be active outside.
Windows
- Arusha
- Fine to open; close them if you are sensitive to pollution.
- Mwanza
- Open them to air the house.
Masks
- Arusha
- Not needed for most people.
- Mwanza
- Not needed.
Air purifier
- Arusha
- Worth running if you are sensitive.
- Mwanza
- Not needed.
Against everywhere else
How do Arusha and Mwanza compare with the rest of the world?
Right now Arusha's air is cleaner than 26% of the 5,420 places Airleaf tracks, and Mwanza's is cleaner than 88%. Within Tanzania, that is 6% and 94% of its 34 measured places.
Cleaner air than…
- Arusha
- Beats 26%
- Mwanza
- Beats 88%
More tree cover than…
- Arusha
- Beats 71%
- Mwanza
- Beats 55%
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, Arusha or Mwanza?
Arusha has lost more: about 771 ha of forest within 10 km of its center from 2001 to 2025, against 28 ha around Mwanza. 18 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: 2001, with 202 ha lost.
Worst year: 2007, with 10 ha lost.
| Arusha | Mwanza | |
|---|---|---|
| Forest lost since 2001Cleared, burned or logged. | 771 ha | 28 ha (better) |
| Share of its forestOf what it had in 2000. | 19% | 10% (better) |
| Cleared for goodTurned into farms, mines or towns. | 18 ha (better) | 24 ha |
| Recent trend2021–2025 against the five years before. | Too little to call | Too little to call |
| Main known cause | Logging (96%) | Towns and roads (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.
Arusha
2017: satellite photo from February 2017 of a 5 × 5 km area about 7 km northeast of the city center.
Mwanza
2017: satellite photo from June 2017 of a 5 × 5 km area in the city center.
Trees
Which has more trees, Arusha or Mwanza?
Arusha has more tree cover: 31.4% of the land within 2 km of its center against 23.5% around Mwanza, or about 98,646 trees against 56,256.
The dark mark is each place's canopy target: 30% of the land, raised where air quality is poor.
| Arusha | Mwanza | |
|---|---|---|
| Trees standingEstimated from the canopy area. | 98.6K (better) | 56.3K |
| Trees still neededTo reach the target. Fewer is better. | 0 (better) | 15.6K |
| CO₂ absorbed each yearBy the trees already standing. | 2.2M kg (better) | 1.2M 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
Arusha vs Mwanza: your questions answered
Is Mwanza cleaner than Arusha?
On air quality, yes, right now: Mwanza reads AQI 21 against 90, a gap of 69 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, Mwanza averaged AQI 34 against 42, and it was the cleaner of the two on 5 of those days.
Is it safe to exercise outdoors in Arusha and Mwanza today?
In Arusha, at AQI 90: Unusually sensitive people should consider limiting long outdoor exertion. In Mwanza, at AQI 21: Air quality is satisfactory for everyone.
Which has lost more forest, Arusha or Mwanza?
Arusha has lost more: about 771 ha of forest within 10 km of its center from 2001 to 2025, against 28 ha around Mwanza. 18 ha of that was cleared for good, for farms, mines or towns.
Which has more trees, Arusha or Mwanza?
Arusha has more tree cover: 31.4% of the land within 2 km of its center against 23.5% around Mwanza, or about 98,646 trees against 56,256. Both figures describe the same-sized circle of ground around each center, not the whole municipality.
How many more trees do Arusha and Mwanza need?
Arusha needs about 0 more to reach its canopy target of 30%, and Mwanza about 15,560 to reach 30%. The target starts at 30% of the land and rises where air quality is poor.
Are Arusha and Mwanza 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 Arusha vs Mwanza 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 17, 2026), and the forest figures are published yearly.
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