Hanoi air quality today
Live AQI for Hanoi (Hà Nội), taken from the monitoring station nearest the city centre and refreshed while this page is open. Below: what the level means for your health, why the air here behaves the way it does, and the questions people ask most.
Station Hanoi, Vietnam (Hà Nội) · ~4 km away · updated 18:00 26/07/2026 (UTC+7) · Source: WAQI (aqicn.org)
Who this level affects
Most people, including children and older adults.
What to do right now
- Outdoor exercise is a good choice today.
- Open windows to air the house out.
Why Hanoi's air behaves this way
Hanoi sits in the middle of the Red River Delta, on low, flat ground with no hills to channel wind. When the air is still, whatever is emitted stays roughly where it was emitted, so the city's readings track the weather as closely as they track the amount of pollution released.
When it gets worse, and why
Roughly October through March is the hardest stretch. Cold, dry air arriving from the north creates a temperature inversion: a layer of warmer air sits on top of the cold air near the ground and acts like an upturned lid holding dust underneath. Readings are therefore usually highest late at night and early in the morning, easing once the sun is strong enough to break that lid around midday.
Main pollution sources in Hanoi
- City traffic: very dense motorbike and car use, with long rush-hour congestion
- Construction sites and the material trucks serving them
- Rice-straw burning in the outlying districts after each harvest
- Craft villages and small workshops mixed into peri-urban neighbourhoods
What the AQI numbers mean
Aiora uses the US-EPA AQI bands, the same scale the monitoring network reports on. Each band below shows who it affects and what to do at that level.
Who it affects: Most people, including children and older adults.
What to do: Outdoor exercise is a good choice today. Open windows to air the house out.
Who it affects: People with asthma or heart conditions may notice mild symptoms.
What to do: Keep long, hard outdoor sessions shorter. Watch for coughing or tightness and ease off if it appears.
Who it affects: Sensitive groups: asthma, COPD, heart disease, pregnancy, children, older adults.
What to do: Move hard exercise indoors. Wear a well-fitting mask on the street. Run an air purifier in the room you sleep in.
Who it affects: Everyone can feel this; people with asthma or heart disease feel it first.
What to do: Avoid outdoor exercise. Keep windows shut and filter indoor air. Keep reliever medication within reach if you have asthma.
Who it affects: Everyone, with a serious risk for sensitive groups.
What to do: Stay indoors as much as you can. Seal gaps around windows and doors. Seek care if breathing gets hard.
Who it affects: Everyone, at emergency level.
What to do: Stay indoors. Use an air purifier continuously. Get medical help for any breathing difficulty.
Frequently asked questions
Why is Hanoi's air usually worst in winter?
Not because more is emitted in winter, but because the air is trapped. The inversion that forms on cold, dry days stops dust from rising and dispersing, so the same amount of emission produces a much higher reading than it would in the rainy, windy summer.
When is the best time to exercise outdoors in Hanoi?
During the inversion season the early-morning slot many people prefer often coincides with the day's peak reading. Late morning or early afternoon is usually easier on the lungs. Check the number on this page before heading out rather than keeping a fixed routine.
Where does this data come from?
Readings come from public monitoring stations via the World Air Quality Index Project (aqicn.org), with additional station coverage from OpenAQ and forecasts from Open-Meteo. The number is the station's measurement, not an estimate by Aiora.
Get an alert before the air turns bad
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Station data: World Air Quality Index Project (aqicn.org) · OpenAQ · Open-Meteo