Air quality comparison · Japan, 251 km apart
Nagoya vs Yokohama Air quality index (AQI) today
Nagoya has cleaner air than Yokohama right now: AQI 33 (Good) against 56 (Moderate).
That puts them in different EPA bands, so the health advice differs today. Over the past 6 days, on modeled daily averages, Nagoya averaged AQI 49 against 73, and it was the cleaner of the two on 6 of those days. Yokohama has lost more forest since 2001. Yokohama has more tree cover.
Updated . Lower is better on the US EPA index: 0–50 is Good, above 300 is Hazardous. Measured by Airleaf.
Nagoya33Yokohama56
Head to head
Nagoya vs Yokohama at a glance
Nagoya is ahead on 4 of 6 measures, and Yokohama on 2. The better figure in each row is marked.
| Nagoya | Yokohama | |
|---|---|---|
| Air quality nowUS AQI. Lower is better. | 33 (better) | 56 |
| PM2.5Fine particles, µg/m³. | 6 (better) | 12 |
| Past week's averageUS AQI, 6 days. | 49 (better) | 73 |
| Forest lost since 2001Within 10 km of the center. | 9 ha (better) | 19 ha |
| Tree coverWithin 2 km of the center. | 9.0% | 17.9% (better) |
| Trees still neededTo reach a healthy canopy. | 61.8K | 31.7K (better) |
Air quality today
What is the air like in Nagoya and Yokohama right now?
Nagoya has cleaner air than Yokohama right now: AQI 33 (Good) against 56 (Moderate). PM2.5 is setting the index in both.
Both readings come from nearby ground stations.
NagoyaYokohama
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).
Nagoya: Ground station · Nagoya (名古屋), 0 m away · median of 3 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).
Yokohama: Ground station · Yokohama (横浜), 1.6 km away. Data: World Air Quality Index Project, Kanagawa Prefectural Environmental Science Research Center, Environmental Monitoring Information Division (神奈川県環境科学センター 環境監視情報課), Japan Atmospheric Environmental Regional Observation System (環境省大気汚染物質広域監視システム).
The past week
Which had cleaner air over the past 6 days?
Over the past 6 days, on modeled daily averages, Nagoya averaged AQI 49 against 73, 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
- Nagoya6Yokohama0
- Average AQI
- Nagoya49Yokohama73
- Worst day, AQI
- Nagoya67Yokohama107
The daily numbers (6 days)
| Day | Nagoya | Yokohama |
|---|---|---|
| Nov 5 | 56 | 72 |
| Nov 6 | 54 | 107 |
| Nov 7 | 31 | 61 |
| Nov 8 | 44 | 68 |
| Nov 9 | 67 | 68 |
| Nov 10 | 40 | 61 |
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 Nagoya and Yokohama today?
Nagoya (AQI 33, Good): Air quality is satisfactory for everyone.
Yokohama (AQI 56, Moderate): Unusually sensitive people should consider limiting long outdoor exertion.
Exercise outdoors
- Nagoya
- A good day to be active outside.
- Yokohama
- Fine for most people; unusually sensitive people should take long or hard exercise easier.
Windows
- Nagoya
- Open them to air the house.
- Yokohama
- Fine to open; close them if you are sensitive to pollution.
Masks
- Nagoya
- Not needed.
- Yokohama
- Not needed for most people.
Air purifier
- Nagoya
- Not needed.
- Yokohama
- Worth running if you are sensitive.
Against everywhere else
How do Nagoya and Yokohama compare with the rest of the world?
Right now Nagoya's air is cleaner than 76% of the 5,420 places Airleaf tracks, and Yokohama's is cleaner than 52%. Within Japan, that is 50% and 2% of its 207 measured places.
Cleaner air than…
- Nagoya
- Beats 76%
- Yokohama
- Beats 52%
More tree cover than…
- Nagoya
- Beats 19%
- Yokohama
- Beats 41%
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, Nagoya or Yokohama?
Yokohama has lost more: about 19 ha of forest within 10 km of its center from 2001 to 2025, against 9 ha around Nagoya. 14 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: 2010, with 2 ha lost.
Worst year: 2004, with 3 ha lost.
| Nagoya | Yokohama | |
|---|---|---|
| Forest lost since 2001Cleared, burned or logged. | 9 ha (better) | 19 ha |
| Share of its forestOf what it had in 2000. | 1.4% | 1.4% (better) |
| Cleared for goodTurned into farms, mines or towns. | 6 ha (better) | 14 ha |
| Recent trend2021–2025 against the five years before. | Too little to call | Too little to call |
| Main known cause | Towns and roads (67%) | Towns and roads (72%) |
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.
Nagoya
2017: satellite photo from August 2017 of a 5 × 5 km area in the city center.
Yokohama
2017: satellite photo from July 2017 of a 5 × 5 km area in the city center.
Trees
Which has more trees, Nagoya or Yokohama?
Yokohama has more tree cover: 17.9% of the land within 2 km of its center against 9.0% around Nagoya, or about 46,956 trees against 26,493.
The dark mark is each place's canopy target: 30% of the land, raised where air quality is poor.
| Nagoya | Yokohama | |
|---|---|---|
| Trees standingEstimated from the canopy area. | 26.5K | 47.0K (better) |
| Trees still neededTo reach the target. Fewer is better. | 61.8K | 31.7K (better) |
| CO₂ absorbed each yearBy the trees already standing. | 583K kg | 1.0M 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
Nagoya vs Yokohama: your questions answered
Is Nagoya cleaner than Yokohama?
On air quality, yes, right now: Nagoya reads AQI 33 against 56, a gap of 23 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, Nagoya averaged AQI 49 against 73, and it was the cleaner of the two on 6 of those days.
Is it safe to exercise outdoors in Nagoya and Yokohama today?
In Nagoya, at AQI 33: Air quality is satisfactory for everyone. In Yokohama, at AQI 56: Unusually sensitive people should consider limiting long outdoor exertion.
Which has lost more forest, Nagoya or Yokohama?
Yokohama has lost more: about 19 ha of forest within 10 km of its center from 2001 to 2025, against 9 ha around Nagoya. 14 ha of that was cleared for good, for farms, mines or towns.
Which has more trees, Nagoya or Yokohama?
Yokohama has more tree cover: 17.9% of the land within 2 km of its center against 9.0% around Nagoya, or about 46,956 trees against 26,493. Both figures describe the same-sized circle of ground around each center, not the whole municipality.
How many more trees do Nagoya and Yokohama need?
Nagoya needs about 61,817 more to reach its canopy target of 30%, and Yokohama about 31,741 to reach 30%. The target starts at 30% of the land and rises where air quality is poor.
Are Nagoya and Yokohama 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 Nagoya vs Yokohama 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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