Air quality comparison · Vietnam, 28 km apart
Hoa Lư vs Nam Định Air quality index (AQI) today
Hoa Lư has cleaner air than Nam Định right now: AQI 47 (Good) against 58 (Moderate).
That puts them in different EPA bands, so the health advice differs today. Over the past 6 days, on modeled daily averages, Hoa Lư averaged AQI 67 against 68, and it was the cleaner of the two on 1 of those days. Hoa Lư has lost more forest since 2001. Nam Định has more tree cover.
Updated . Lower is better on the US EPA index: 0–50 is Good, above 300 is Hazardous. Measured by Airleaf.
Hoa Lư47Nam Định58
Head to head
Hoa Lư vs Nam Định at a glance
Hoa Lư and Nam Định are level, each ahead on 3 of 6 measures. The better figure in each row is marked.
| Hoa Lư | Nam Định | |
|---|---|---|
| Air quality nowUS AQI. Lower is better. | 47 (better) | 58 |
| PM2.5Fine particles, µg/m³. | 9.5 (better) | 11 |
| Past week's averageUS AQI, 6 days. | 67 (better) | 68 |
| Forest lost since 2001Within 10 km of the center. | 66 ha | 10 ha (better) |
| Tree coverWithin 2 km of the center. | 27.5% | 29.0% (better) |
| Trees still neededTo reach a healthy canopy. | 7.5K | 3.0K (better) |
Air quality today
What is the air like in Hoa Lư and Nam Định right now?
Hoa Lư has cleaner air than Nam Định right now: AQI 47 (Good) against 58 (Moderate). PM2.5 is setting the index in both.
Both readings are model estimates, with no ground station close enough to either.
Hoa LưNam Định
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).
Hoa Lư: Estimate · model corrected with 5 station cities within 105 km, e.g. Duong Hao and Gia Lâm. Data: Open-Meteo / CAMS, corrected with 5 ground-station cities within 105 km, US EPA index.
Nam Định: Estimate · model corrected with 5 station cities within 85 km, e.g. Duong Hao and Gia Lâm. Data: Open-Meteo / CAMS, corrected with 5 ground-station cities within 85 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, Hoa Lư averaged AQI 67 against 68, and it was the cleaner of the two on 1 of those days. The two are close enough that the air model behind these daily figures barely separates them, so their lines nearly overlap.
- Cleaner days
- Hoa Lư1Nam Định0
- Average AQI
- Hoa Lư67Nam Định68
- Worst day, AQI
- Hoa Lư77Nam Định77
The daily numbers (6 days)
| Day | Hoa Lư | Nam Định |
|---|---|---|
| Nov 5 | 77 | 77 |
| Nov 6 | 77 | 77 |
| Nov 7 | 67 | 67 |
| Nov 8 | 68 | 68 |
| Nov 9 | 55 | 55 |
| Nov 10 | 60 | 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 Hoa Lư and Nam Định today?
Hoa Lư (AQI 47, Good): Air quality is satisfactory for everyone.
Nam Định (AQI 58, Moderate): Unusually sensitive people should consider limiting long outdoor exertion.
Exercise outdoors
- Hoa Lư
- A good day to be active outside.
- Nam Định
- Fine for most people; unusually sensitive people should take long or hard exercise easier.
Windows
- Hoa Lư
- Open them to air the house.
- Nam Định
- Fine to open; close them if you are sensitive to pollution.
Masks
- Hoa Lư
- Not needed.
- Nam Định
- Not needed for most people.
Air purifier
- Hoa Lư
- Not needed.
- Nam Định
- Worth running if you are sensitive.
Against everywhere else
How do Hoa Lư and Nam Định compare with the rest of the world?
Right now Hoa Lư's air is cleaner than 64% of the 5,420 places Airleaf tracks, and Nam Định's is cleaner than 50%. Within Vietnam, that is 60% and 30% of its 114 measured places.
Cleaner air than…
- Hoa Lư
- Beats 64%
- Nam Định
- Beats 50%
More tree cover than…
- Hoa Lư
- Beats 63%
- Nam Định
- Beats 67%
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, Hoa Lư or Nam Định?
Hoa Lư has lost more: about 66 ha of forest within 10 km of its center from 2001 to 2025, against 10 ha around Nam Định. 50 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: 2017, with 16 ha lost.
Worst year: 2001, with 2 ha lost.
| Hoa Lư | Nam Định | |
|---|---|---|
| Forest lost since 2001Cleared, burned or logged. | 66 ha | 10 ha (better) |
| Share of its forestOf what it had in 2000. | 2.6% (better) | 7.4% |
| Cleared for goodTurned into farms, mines or towns. | 50 ha | 2 ha (better) |
| Recent trend2021–2025 against the five years before. | Too little to call | Too little to call |
| Main known cause | Mining and energy (58%) | Towns and roads (13%) |
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.
Hoa Lư
2017: satellite photo from December 2017 of a 5 × 5 km area about 7 km southwest of the city center.
Nam Định
2017: satellite photo from December 2017 of a 5 × 5 km area in the city center.
Trees
Which has more trees, Hoa Lư or Nam Định?
Nam Định has more tree cover: 29.0% of the land within 2 km of its center against 27.5% around Hoa Lư, or about 87,189 trees against 82,765.
The dark mark is each place's canopy target: 30% of the land, raised where air quality is poor.
| Hoa Lư | Nam Định | |
|---|---|---|
| Trees standingEstimated from the canopy area. | 82.8K | 87.2K (better) |
| Trees still neededTo reach the target. Fewer is better. | 7.5K | 3.0K (better) |
| CO₂ absorbed each yearBy the trees already standing. | 1.8M kg | 1.9M 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
Hoa Lư vs Nam Định: your questions answered
Is Hoa Lư cleaner than Nam Định?
On air quality, yes, right now: Hoa Lư reads AQI 47 against 58, a gap of 11 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, Hoa Lư averaged AQI 67 against 68, and it was the cleaner of the two on 1 of those days.
Is it safe to exercise outdoors in Hoa Lư and Nam Định today?
In Hoa Lư, at AQI 47: Air quality is satisfactory for everyone. In Nam Định, at AQI 58: Unusually sensitive people should consider limiting long outdoor exertion.
Which has lost more forest, Hoa Lư or Nam Định?
Hoa Lư has lost more: about 66 ha of forest within 10 km of its center from 2001 to 2025, against 10 ha around Nam Định. 50 ha of that was cleared for good, for farms, mines or towns.
Which has more trees, Hoa Lư or Nam Định?
Nam Định has more tree cover: 29.0% of the land within 2 km of its center against 27.5% around Hoa Lư, or about 87,189 trees against 82,765. Both figures describe the same-sized circle of ground around each center, not the whole municipality.
How many more trees do Hoa Lư and Nam Định need?
Hoa Lư needs about 7,524 more to reach its canopy target of 30%, and Nam Định about 3,007 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 Hoa Lư and Nam Định 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 Hoa Lư vs Nam Định 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 4, 2026 and Sep 9, 2026), and the forest figures are published yearly.
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