Air quality
Air quality in Hoàn Kiếm today
Updated
Unhealthy for Sensitive Groups (US AQI 104) People with heart or lung disease, older adults, children and teens should cut back on prolonged or heavy exertion outdoors. Model estimate for Mon, Oct 26, 7:00 am (00:00 UTC).
Live AQI, PM2.5, PM10 and ozone for Hoàn Kiếm, Hanoi, Vietnam, with a 48-hour forecast and the best time to be outside.
- US AQI now
- 104 Unhealthy for Sensitive Groups
- PM2.5
- 31 µg/m³ 2.1× WHO 24-h guideline
- PM10
- 33 µg/m³
- Ozone
- 81 µg/m³
- Dominant pollutant
- PM2.5 sub-index 104
- Best hour today
- 2:00 pm AQI 99
- European AQI
- 49
Air quality in Hoàn Kiếm right now
Right now the modelled US Air Quality Index for Hoàn Kiếm, Hanoi, Vietnam is 104, which falls in the "Unhealthy for Sensitive Groups" band (up to 150). People with heart or lung disease, older adults, children and teens should cut back on prolonged or heavy exertion outdoors.
The index is driven mainly by PM2.5, whose own sub-index is 104. Fine and coarse particles come from traffic, heating, industry, dust and smoke; they build up on calm nights and clear when wind or rain arrives.
PM2.5 is 31 µg/m³, 2.1 times the WHO 24-hour guideline of 15 µg/m³; PM10 is 33 µg/m³ against a guideline of 45; ozone is 81 µg/m³ (below the WHO 8-hour level of 100); nitrogen dioxide is 22 µg/m³ (below the 24-hour guideline of 25).
Also this hour: carbon monoxide 679 µg/m³.
Hoàn Kiếm AQI forecast: next 48 hours
Over the next 24 hours the AQI is forecast to range from 99 around Mon 2:00 pm to 158 around Mon 6:00 pm, from "Moderate" at best to "Unhealthy" at worst.
The following day is expected to be worse, averaging about 155 against 118 for the next 24 hours.
| Local time (Asia/Bangkok) | US AQI | Category | PM2.5 µg/m³ | PM10 µg/m³ | Ozone µg/m³ |
|---|---|---|---|---|---|
| Mon 7:00 am | 104 | Unhealthy for Sensitive Groups | 31.4 | 33 | 81 |
| Mon 10:00 am | 102 | Unhealthy for Sensitive Groups | 24 | 27 | 147 |
| Mon 1:00 pm | 100 | Moderate | 26.4 | 27 | 194 |
| Mon 4:00 pm | 142 | Unhealthy for Sensitive Groups | 32.1 | 33 | 168 |
| Mon 7:00 pm | 152 | Unhealthy | 33.9 | 35 | 87 |
| Mon 10:00 pm | 100 | Moderate | 65.9 | 70 | 28 |
| Tue 1:00 am | 114 | Unhealthy for Sensitive Groups | 87.8 | 91 | 7 |
| Tue 4:00 am | 124 | Unhealthy for Sensitive Groups | 74.7 | 75 | 25 |
| Tue 7:00 am | 133 | Unhealthy for Sensitive Groups | 76.4 | 77 | 30 |
| Tue 10:00 am | 147 | Unhealthy for Sensitive Groups | 52 | 53 | 167 |
| Tue 1:00 pm | 151 | Unhealthy | 38.4 | 39 | 199 |
| Tue 4:00 pm | 152 | Unhealthy | 37 | 38 | 182 |
| Tue 7:00 pm | 163 | Unhealthy | 81.7 | 82 | 67 |
| Tue 10:00 pm | 157 | Unhealthy | 99.7 | 101 | 44 |
| Wed 1:00 am | 160 | Unhealthy | 113.4 | 114 | 32 |
| Wed 4:00 am | 162 | Unhealthy | 96.9 | 97 | 26 |
| Wed 7:00 am | 164 | Unhealthy | 90.8 | 91 | 24 |
Every third hour of the CAMS forecast via Open-Meteo. US AQI uses rolling averages (24 h for particles, 8 h for ozone), so it moves more slowly than the hourly concentrations.
Best time to be outside in Hoàn Kiếm today
Between 6 am and 9 pm local time, the cleanest air today is forecast around 2:00 pm (AQI 99, Moderate) and the worst around 6:00 pm (AQI 158). That is a swing of 59 points, so a run or walk around 2:00 pm is noticeably better.
Hoàn Kiếm vs the rest of Vietnam
Across 68 Vietnam cities we track, the average US AQI right now is 84 (Moderate). Hoàn Kiếm at 104 is 20 points worse than average.
It ranks 67 of 68 from cleanest to most polluted; the cleanest is Phu Quoc (36) and the most polluted Mỹ Hào (118).
For context, the median across 3,909 cities worldwide is 57.
Air quality in cities near Hoàn Kiếm
| City | Distance | US AQI | Category | PM2.5 µg/m³ |
|---|---|---|---|---|
| Hanoi | 1 km | 118 | Unhealthy for Sensitive Groups | 36.2 |
| Hai Bà Trưng | 2 km | 118 | Unhealthy for Sensitive Groups | 36.2 |
| Ba Dinh | 3 km | 118 | Unhealthy for Sensitive Groups | 36.2 |
| Đống Đa | 3 km | 118 | Unhealthy for Sensitive Groups | 36.2 |
| Tương Mai | 4 km | 118 | Unhealthy for Sensitive Groups | 36.2 |
| Long Bien | 5 km | 118 | Unhealthy for Sensitive Groups | 36.2 |
| Cầu Giấy | 5 km | 118 | Unhealthy for Sensitive Groups | 36.2 |
| Tây Hồ | 6 km | 118 | Unhealthy for Sensitive Groups | 36.2 |
Model vs measured
We found no measured PM2.5 sensor cell within 25 km of Hoàn Kiếm, so the numbers on this page are model estimates. Models capture regional pollution well but can miss very local sources such as a busy road or a nearby fire.
Wildfire smoke
PM2.5 is forecast to reach 94 µg/m³ in the next 24 hours while NASA satellites detected 143 fire hotspots within 300 km in the last day (nearest about 30 km away). Smoke is a likely contributor: keep windows closed, run an air purifier or HVAC filter, and check the fire map before heading out.
Advice for sensitive groups
At 104, children, older adults, pregnant people and anyone with asthma, COPD or heart disease should limit time outdoors, especially strenuous activity. A well-fitted N95/FFP2 mask cuts particle exposure; it does not filter ozone.
What the US AQI numbers mean
| US AQI | Category | What it means |
|---|---|---|
| 0-50 | Good | Air quality is satisfactory and poses little or no risk; a good time for outdoor activity. |
| 51-100 | Moderate | Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors. |
| 101-150 | Unhealthy for Sensitive Groups | People with heart or lung disease, older adults, children and teens should cut back on prolonged or heavy exertion outdoors. |
| 151-200 | Unhealthy | Everyone should reduce prolonged or heavy exertion outdoors; sensitive groups should avoid it and keep windows closed. |
| 201-300 | Very Unhealthy | Health alert: everyone should avoid prolonged or heavy exertion outdoors, and sensitive groups should stay indoors. |
| 301-500 | Hazardous | Emergency conditions: everyone should avoid all outdoor physical activity and stay indoors with filtered air if possible. The scale tops out at 500; heavier dust or smoke is shown as 500. |
Values on this page are modelled by CAMS (Copernicus) and served by Open-Meteo; they are estimates for the area around the city centre, not readings from an official monitor.
Nearby cities
More for Hoàn Kiếm
Air quality elsewhere
Data: Open-Meteo Air Quality API, Copernicus Atmosphere Monitoring Service (CAMS), NASA FIRMS.