Air quality comparison · Kenya, 56 km apart
Mwala vs Thika Air quality index (AQI) today
Mwala has cleaner air than Thika right now: AQI 52 (Moderate) against 62 (Moderate).
Both sit in the same EPA band, so the health advice is the same for each today. Over the past 6 days, on modeled daily averages, Mwala averaged AQI 33 against 37, and it was the cleaner of the two on 5 of those days. Thika has lost more forest since 2001. Thika has more tree cover.
Updated . Lower is better on the US EPA index: 0–50 is Good, above 300 is Hazardous. Measured by Airleaf.
Mwala52Thika62
Head to head
Mwala vs Thika at a glance
Mwala is ahead on 4 of 6 measures, and Thika on 2. The better figure in each row is marked.
| Mwala | Thika | |
|---|---|---|
| Air quality nowUS AQI. Lower is better. | 52 (better) | 62 |
| PM2.5Fine particles, µg/m³. | 8.7 (better) | 16.7 |
| Past week's averageUS AQI, 6 days. | 33 (better) | 37 |
| Forest lost since 2001Within 10 km of the center. | 34 ha (better) | 303 ha |
| Tree coverWithin 2 km of the center. | 8.4% | 25.2% (better) |
| Trees still neededTo reach a healthy canopy. | 67.9K | 15.0K (better) |
Air quality today
What is the air like in Mwala and Thika right now?
Mwala has cleaner air than Thika right now: AQI 52 (Moderate) against 62 (Moderate). PM2.5 is setting the index in both.
Thika's PM2.5 is about 1.1× the WHO's 24-hour guideline of 15 µg/m³.
Both readings are model estimates, with no ground station close enough to either.
MwalaThika
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).
Mwala: Estimate · model corrected with 5 station cities within 85 km, e.g. Ruiru and Nairobi. Data: Open-Meteo / CAMS, corrected with 5 ground-station cities within 85 km, US EPA index.
Thika: Estimate · model corrected with 4 station cities within 45 km, e.g. Ruiru and Kiambu. Data: Open-Meteo / CAMS, corrected with 4 ground-station cities within 45 km, US EPA index.
The past week
Which had cleaner air over the past 6 days?
Over the past 6 days, on modeled daily averages, Mwala averaged AQI 33 against 37, 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
- Mwala5Thika1
- Average AQI
- Mwala33Thika37
- Worst day, AQI
- Mwala40Thika46
The daily numbers (6 days)
| Day | Mwala | Thika |
|---|---|---|
| Nov 5 | 32 | 36 |
| Nov 6 | 36 | 39 |
| Nov 7 | 40 | 46 |
| Nov 8 | 28 | 34 |
| Nov 9 | 24 | 33 |
| Nov 10 | 39 | 36 |
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 Mwala and Thika 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 Mwala and Thika compare with the rest of the world?
Right now Mwala's air is cleaner than 58% of the 5,420 places Airleaf tracks, and Thika's is cleaner than 45%. Within Kenya, that is 68% and 56% of its 26 measured places.
Cleaner air than…
- Mwala
- Beats 58%
- Thika
- Beats 45%
More tree cover than…
- Mwala
- Beats 17%
- Thika
- Beats 58%
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, Mwala or Thika?
Thika has lost more: about 303 ha of forest within 10 km of its center from 2001 to 2025, against 34 ha around Mwala. 221 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 6 ha lost.
Worst year: 2001, with 46 ha lost.
| Mwala | Thika | |
|---|---|---|
| Forest lost since 2001Cleared, burned or logged. | 34 ha (better) | 303 ha |
| Share of its forestOf what it had in 2000. | 14% (better) | 19% |
| Cleared for goodTurned into farms, mines or towns. | 30 ha (better) | 221 ha |
| Recent trend2021–2025 against the five years before. | Too little to call | Too little to call |
| Main known cause | Farms, pasture and plantations (89%) | Farms, pasture and plantations (68%) |
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.
Mwala
2017: satellite photo from January 2017 of a 5 × 5 km area in the city center.
Thika
2017: satellite photo from January 2017 of a 5 × 5 km area about 6 km northwest of the city center.
Trees
Which has more trees, Mwala or Thika?
Thika has more tree cover: 25.2% of the land within 2 km of its center against 8.4% around Mwala, or about 78,931 trees against 26,389.
The dark mark is each place's canopy target: 30% of the land, raised where air quality is poor.
| Mwala | Thika | |
|---|---|---|
| Trees standingEstimated from the canopy area. | 26.4K | 78.9K (better) |
| Trees still neededTo reach the target. Fewer is better. | 67.9K | 15.0K (better) |
| CO₂ absorbed each yearBy the trees already standing. | 581K kg | 1.7M 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
Mwala vs Thika: your questions answered
Is Mwala cleaner than Thika?
On air quality, yes, right now: Mwala reads AQI 52 against 62, a gap of 10 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 6 days, on modeled daily averages, Mwala averaged AQI 33 against 37, and it was the cleaner of the two on 5 of those days.
Is it safe to exercise outdoors in Mwala and Thika today?
The advice is the same for both today. Unusually sensitive people should consider limiting long outdoor exertion. Mwala reads AQI 52 and Thika reads AQI 62.
Which has lost more forest, Mwala or Thika?
Thika has lost more: about 303 ha of forest within 10 km of its center from 2001 to 2025, against 34 ha around Mwala. 221 ha of that was cleared for good, for farms, mines or towns.
Which has more trees, Mwala or Thika?
Thika has more tree cover: 25.2% of the land within 2 km of its center against 8.4% around Mwala, or about 78,931 trees against 26,389. Both figures describe the same-sized circle of ground around each center, not the whole municipality.
How many more trees do Mwala and Thika need?
Mwala needs about 67,858 more to reach its canopy target of 30%, and Thika about 15,034 to reach 30%. The target starts at 30% of the land and rises where air quality is poor.
Why can two places 56 km apart read differently?
Air changes over short distances with traffic, industry, wind and hills, and each reading comes from the nearest ground stations or, where there are none, from a regional model. A gap of a few points between neighbors is within normal variation, while a gap that crosses an EPA band is worth noticing.
Are Mwala and Thika 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 Mwala vs Thika 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 24, 2026 and Sep 24, 2026), and the forest figures are published yearly.
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