Air quality comparison · Vietnam, 1222 km apart
Cần Thơ vs Hanoi Air quality index (AQI) today
Cần Thơ has cleaner air than Hanoi right now: AQI 31 (Good) against 162 (Unhealthy).
That puts them in different EPA bands, so the health advice differs today. Over the past 7 days, on modeled daily averages, Cần Thơ averaged AQI 69 against 82, and it was the cleaner of the two on 5 of those days. Cần Thơ has lost more forest since 2001. Cần Thơ has more tree cover.
Updated . Lower is better on the US EPA index: 0–50 is Good, above 300 is Hazardous. Measured by Airleaf.
Cần Thơ31Hanoi162
Head to head
Cần Thơ vs Hanoi at a glance
Cần Thơ is ahead on 5 of 6 measures, and Hanoi on 1. The better figure in each row is marked.
| Cần Thơ | Hanoi | |
|---|---|---|
| Air quality nowUS AQI. Lower is better. | 31 (better) | 162 |
| PM2.5Fine particles, µg/m³. | 4.7 (better) | 71 |
| Past week's averageUS AQI, 7 days. | 69 (better) | 82 |
| Forest lost since 2001Within 10 km of the center. | 50 ha | 11 ha (better) |
| Tree coverWithin 2 km of the center. | 22.0% (better) | 18.7% |
| Trees still neededTo reach a healthy canopy. | 19.6K (better) | 65.6K |
Air quality today
What is the air like in Cần Thơ and Hanoi right now?
Cần Thơ has cleaner air than Hanoi right now: AQI 31 (Good) against 162 (Unhealthy). PM2.5 is setting the index in both.
Hanoi's PM2.5 is about 4.7× the WHO's 24-hour guideline of 15 µg/m³.
Hanoi is read from a nearby ground station and Cần Thơ is a model estimate, so the two are not quite like for like.
Cần ThơHanoi
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).
Cần Thơ: Estimate · model corrected with 4 station cities within 145 km, e.g. Can Giuoc and Ho Chi Minh City. Data: Open-Meteo / CAMS, corrected with 4 ground-station cities within 145 km, US EPA index.
Hanoi: Ground station · Số 1 đường Giải Phóng - phường Bạch Mai - ĐHBK , 2.1 km away · median of 3 stations. Data: OpenAQ · Hanoi Air Quality Monitoring Network, World Air Quality Index Project, UNIS - United Nations International School Of Hanoi.
The past week
Which had cleaner air over the past 7 days?
Over the past 7 days, on modeled daily averages, Cần Thơ averaged AQI 69 against 82, 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
- Cần Thơ5Hanoi2
- Average AQI
- Cần Thơ69Hanoi82
- Worst day, AQI
- Cần Thơ76Hanoi147
The daily numbers (7 days)
| Day | Cần Thơ | Hanoi |
|---|---|---|
| Nov 5 | 69 | 73 |
| Nov 6 | 70 | 80 |
| Nov 7 | 76 | 77 |
| Nov 8 | 71 | 91 |
| Nov 9 | 70 | 44 |
| Nov 10 | 70 | 61 |
| Nov 11 | 60 | 147 |
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 Cần Thơ and Hanoi today?
Cần Thơ (AQI 31, Good): Air quality is satisfactory for everyone.
Hanoi (AQI 162, Unhealthy): Everyone should limit long outdoor exertion; sensitive groups more so.
Exercise outdoors
- Cần Thơ
- A good day to be active outside.
- Hanoi
- Everyone should cut down long or hard exercise; sensitive groups should avoid it.
Windows
- Cần Thơ
- Open them to air the house.
- Hanoi
- Keep them closed.
Masks
- Cần Thơ
- Not needed.
- Hanoi
- Wear an N95 outdoors.
Air purifier
- Cần Thơ
- Not needed.
- Hanoi
- Run one.
Against everywhere else
How do Cần Thơ and Hanoi compare with the rest of the world?
Right now Cần Thơ's air is cleaner than 79% of the 5,420 places Airleaf tracks, and Hanoi's is cleaner than 7%. Within Vietnam, that is 63% and 0% of its 114 measured places.
Cleaner air than…
- Cần Thơ
- Beats 79%
- Hanoi
- Beats 7%
More tree cover than…
- Cần Thơ
- Beats 51%
- Hanoi
- Beats 43%
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, Cần Thơ or Hanoi?
Cần Thơ has lost more: about 50 ha of forest within 10 km of its center from 2001 to 2025, against 11 ha around Hanoi. 30 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 8 ha lost.
Worst year: 2005, with 3 ha lost.
| Cần Thơ | Hanoi | |
|---|---|---|
| Forest lost since 2001Cleared, burned or logged. | 50 ha | 11 ha (better) |
| Cleared for goodTurned into farms, mines or towns. | 30 ha | 4 ha (better) |
| Recent trend2021–2025 against the five years before. | Too little to call | Too little to call |
| Main known cause | Towns and roads (35%) | Towns and roads (34%) |
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.
Cần Thơ
2017: satellite photo from March 2017 of a 5 × 5 km area in the city center.
Hanoi
2017: satellite photo from December 2017 of a 5 × 5 km area in the city center.
Trees
Which has more trees, Cần Thơ or Hanoi?
Cần Thơ has more tree cover: 22.0% of the land within 2 km of its center against 18.7% around Hanoi, or about 53,910 trees against 57,632.
The dark mark is each place's canopy target: 30% of the land, raised where air quality is poor.
| Cần Thơ | Hanoi | |
|---|---|---|
| Trees standingEstimated from the canopy area. | 53.9K | 57.6K (better) |
| Trees still neededTo reach the target. Fewer is better. | 19.6K (better) | 65.6K |
| CO₂ absorbed each yearBy the trees already standing. | 1.2M kg | 1.3M 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
Cần Thơ vs Hanoi: your questions answered
Is Cần Thơ cleaner than Hanoi?
On air quality, yes, right now: Cần Thơ reads AQI 31 against 162, a gap of 131 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, Cần Thơ averaged AQI 69 against 82, and it was the cleaner of the two on 5 of those days.
Is it safe to exercise outdoors in Cần Thơ and Hanoi today?
In Cần Thơ, at AQI 31: Air quality is satisfactory for everyone. In Hanoi, at AQI 162: Everyone should limit long outdoor exertion; sensitive groups more so.
Which has lost more forest, Cần Thơ or Hanoi?
Cần Thơ has lost more: about 50 ha of forest within 10 km of its center from 2001 to 2025, against 11 ha around Hanoi. 30 ha of that was cleared for good, for farms, mines or towns.
Which has more trees, Cần Thơ or Hanoi?
Cần Thơ has more tree cover: 22.0% of the land within 2 km of its center against 18.7% around Hanoi, or about 53,910 trees against 57,632. Both figures describe the same-sized circle of ground around each center, not the whole municipality.
How many more trees do Cần Thơ and Hanoi need?
Cần Thơ needs about 19,604 more to reach its canopy target of 30%, and Hanoi about 65,645 to reach 40%. The target starts at 30% of the land and rises where air quality is poor.
Are Cần Thơ and Hanoi 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. Hanoi is read from a nearby ground station and Cần Thơ 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 Cần Thơ vs Hanoi 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 (Apr 24, 2026 and Aug 10, 2026), and the forest figures are published yearly.
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