Air quality comparison · Japan, 28 km apart
Okazaki vs Toyohashi Air quality index (AQI) today
Toyohashi has cleaner air than Okazaki right now: AQI 9 (Good) against 34 (Good).
Both sit in the same EPA band, so the health advice is the same for each today. Over the past 7 days, on modeled daily averages, both averaged AQI 45. Okazaki has lost more forest since 2001. Okazaki has more tree cover.
Updated . Lower is better on the US EPA index: 0–50 is Good, above 300 is Hazardous. Measured by Airleaf.
Okazaki34Toyohashi9
Head to head
Okazaki vs Toyohashi at a glance
Toyohashi is ahead on 3 of 6 measures, and Okazaki on 2. The better figure in each row is marked.
| Okazaki | Toyohashi | |
|---|---|---|
| Air quality nowUS AQI. Lower is better. | 34 | 9 (better) |
| PM2.5Fine particles, µg/m³. | 6.1 | 1.4 (better) |
| Past week's averageUS AQI, 7 days. | 45 | 45 |
| Forest lost since 2001Within 10 km of the center. | 300 ha | 77 ha (better) |
| Tree coverWithin 2 km of the center. | 12.0% (better) | 5.2% |
| Trees still neededTo reach a healthy canopy. | 56.2K (better) | 75.4K |
Air quality today
What is the air like in Okazaki and Toyohashi right now?
Toyohashi has cleaner air than Okazaki right now: AQI 9 (Good) against 34 (Good). PM2.5 is setting the index in both.
Okazaki is read from a nearby ground station and Toyohashi is a model estimate, so the two are not quite like for like.
OkazakiToyohashi
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).
Okazaki: Ground station · Okazaki (岡崎), 800 m away · median of 2 stations. Data: World Air Quality Index Project, Japan Atmospheric Environmental Regional Observation System (環境省大気汚染物質広域監視システム), Aichi air pollution continuous monitoring results (愛知県大気汚染常時監視結果).
Toyohashi: Estimate · model corrected with 56 station cities within 225 km, e.g. Okazaki and Nishio. Data: Open-Meteo / CAMS, corrected with 56 ground-station cities within 225 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, both averaged AQI 45. The two are close enough that the air model behind these daily figures barely separates them, so their lines nearly overlap.
- Cleaner days
- Okazaki0Toyohashi0
- Average AQI
- Okazaki45Toyohashi45
- Worst day, AQI
- Okazaki65Toyohashi65
The daily numbers (7 days)
| Day | Okazaki | Toyohashi |
|---|---|---|
| Nov 5 | 52 | 52 |
| Nov 6 | 44 | 44 |
| Nov 7 | 27 | 27 |
| Nov 8 | 36 | 36 |
| Nov 9 | 65 | 65 |
| Nov 10 | 47 | 47 |
| Nov 11 | 44 | 44 |
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 Okazaki and Toyohashi today?
Air quality is satisfactory for everyone. Both are in the same EPA band today (Good), so the advice is the same.
Exercise outdoors
A good day to be active outside.
Windows
Open them to air the house.
Masks
Not needed.
Air purifier
Not needed.
Against everywhere else
How do Okazaki and Toyohashi compare with the rest of the world?
Right now Okazaki's air is cleaner than 75% of the 5,420 places Airleaf tracks, and Toyohashi's is cleaner than 96%. Within Japan, that is 49% and 89% of its 207 measured places.
Cleaner air than…
- Okazaki
- Beats 75%
- Toyohashi
- Beats 96%
More tree cover than…
- Okazaki
- Beats 26%
- Toyohashi
- Beats 11%
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, Okazaki or Toyohashi?
Okazaki has lost more: about 300 ha of forest within 10 km of its center from 2001 to 2025, against 77 ha around Toyohashi. 275 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 44 ha lost.
Worst year: 2010, with 8 ha lost.
| Okazaki | Toyohashi | |
|---|---|---|
| Forest lost since 2001Cleared, burned or logged. | 300 ha | 77 ha (better) |
| Share of its forestOf what it had in 2000. | 3.3% | 1.9% (better) |
| Cleared for goodTurned into farms, mines or towns. | 275 ha | 45 ha (better) |
| Recent trend2021–2025 against the five years before. | Too little to call | Too little to call |
| Main known cause | Towns and roads (83%) | Towns and roads (44%) |
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.
Okazaki
2017: satellite photo from September 2017 of a 5 × 5 km area about 7 km north of the city center.
Toyohashi
2017: satellite photo from June 2017 of a 5 × 5 km area in the city center.
Trees
Which has more trees, Okazaki or Toyohashi?
Okazaki has more tree cover: 12.0% of the land within 2 km of its center against 5.2% around Toyohashi, or about 37,435 trees against 15,814.
The dark mark is each place's canopy target: 30% of the land, raised where air quality is poor.
| Okazaki | Toyohashi | |
|---|---|---|
| Trees standingEstimated from the canopy area. | 37.4K (better) | 15.8K |
| Trees still neededTo reach the target. Fewer is better. | 56.2K (better) | 75.4K |
| CO₂ absorbed each yearBy the trees already standing. | 824K kg (better) | 348K 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
Okazaki vs Toyohashi: your questions answered
Is Toyohashi cleaner than Okazaki?
On air quality, yes, right now: Toyohashi reads AQI 9 against 34, a gap of 25 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, both averaged AQI 45.
Is it safe to exercise outdoors in Okazaki and Toyohashi today?
The advice is the same for both today. Air quality is satisfactory for everyone. Okazaki reads AQI 34 and Toyohashi reads AQI 9.
Which has lost more forest, Okazaki or Toyohashi?
Okazaki has lost more: about 300 ha of forest within 10 km of its center from 2001 to 2025, against 77 ha around Toyohashi. 275 ha of that was cleared for good, for farms, mines or towns.
Which has more trees, Okazaki or Toyohashi?
Okazaki has more tree cover: 12.0% of the land within 2 km of its center against 5.2% around Toyohashi, or about 37,435 trees against 15,814. Both figures describe the same-sized circle of ground around each center, not the whole municipality.
How many more trees do Okazaki and Toyohashi need?
Okazaki needs about 56,153 more to reach its canopy target of 30%, and Toyohashi about 75,418 to reach 30%. The target starts at 30% of the land and rises where air quality is poor.
Why can two places 28 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 Okazaki and Toyohashi 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. Okazaki is read from a nearby ground station and Toyohashi is a model estimate, so the two are not quite like for like. Nothing is adjusted for population, city limits or climate.
How often does the Okazaki vs Toyohashi 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 (Aug 24, 2026 and Aug 24, 2026), and the forest figures are published yearly.
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