Is the air quality good in Hanoi?
On December 2 at 9:30 PM PT, Hanoi, Vietnam, recorded poor air quality with an AQI of 208, classified as very unhealthy.
These conditions can negatively affect health for everyone, with especially high risks for children, older adults, pregnant people, and anyone with heart or lung disease (1).
Air quality is dynamic and, like the weather, can change frequently. Hanoi ranks as 4th most polluted major city in the world on Wednesday morning.
Click here for a real-time air quality map of Hanoi.
While air quality conditions in Hanoi today are poor, It is important to note that the average PM2.5 concentration in 2024 for Hanoi was 45 µg/m³. This corresponds to an AQI of 125 (“unhealthy for sensitive groups”) and was 8 times the WHO annual guideline of 5 µg/m³.
Hanoi, Vietnam was the 4th most polluted major city on December 2 at 9:30 PM PT. Source: IQAir.
When will air quality improve in Hanoi?
Air quality is forecasted to improve gradually later in the day as some of the trapped pollutants begin to disperse.
Hourly air quality forecast for Hanoi, Vietnam on December 2. Source: IQAir.
However, regional forecasts from national environment authorities warn that from late November into early December, weather conditions in northern Vietnam are highly unfavorable for dispersing pollution. This means that while short term improvements are possible over the next day or so, episodes of elevated pollution are likely to recur throughout the early winter period.
Air quality map of Hanoi, Vietnam on December 2. Source: IQAir.
What is causing poor air quality in Hanoi?
The current poor air quality in Hanoi is driven by a combination of unfavorable winter weather patterns and multiple pollution sources. Seasonal temperature inversions, light winds, and persistent fog trap fine particulate matter near the ground, preventing pollutants from dispersing and allowing smog to build up over the city and surrounding provinces (2).
Key contributors to the air pollution include:
- Industrial emissions from steel mills, coal fired power plants, cement factories, chemical producers, fertilizer plants, and other heavy industries in northern Vietnam, which are being required to run emission controls at full efficiency and to reduce output on high AQI days (3).
- Exhaust from road traffic and aging vehicles, especially trucks and material transport vehicles that emit visible black smoke or travel without proper covering, which are being targeted for stricter enforcement during this episode.
- Dust and particulate matter from construction sites and major transport projects, where authorities have ordered perimeter screening, mist spraying, and vehicle washing, with suspension of work on days with hazardous air (4).
- Open burning of trash, crop residues, and other waste in and around Hanoi, which local governments have been instructed to detect and stop using remote monitoring tools and field inspections.
- Household and small scale combustion sources, including the use of honeycomb charcoal stoves and other high emission fuels in residential and craft village settings, which city directives now aim to phase out or tightly control.
Together with stagnant winter air, these sources generate high levels of fine particulate pollution (PM2.5) and other pollutants, leading to repeated smog events and AQI readings in the unhealthy to very unhealthy range across Hanoi and nearby provinces (5).
How can I protect myself from poor air quality?
- Get a free air quality app for real-time air quality alerts and forecasts.
- Shut doors and windows and set the HVAC to recirculate mode.
- Contribute to your community’s outdoor air quality data.
- Stay indoors when air quality is poor; if you do need to go outdoors, wear a KN95/FFP2 mask.
- Run a high-performance air purifier to filter particles, gases, and other pollutants.
