Short answer. Vietnam's official index, VN_AQI, runs from 0-50 (good, green) to 301-500 (hazardous, brown), with advice for each level (Decision 1459/QĐ-TCMT, 2019) 1. Hourly readings by station are on cem.gov.vn 2. Above 150 (bad), everyone should cut strenuous outdoor activity; at 301 and above, stay indoors with doors and windows shut 1. Average fine-particle levels are well above the WHO guideline 34.
Where can I check air quality right now?
The Northern Environmental Monitoring Centre, part of the Department of Environment of the Ministry of Agriculture and Environment, shows an hourly "VN_AQI giờ" table by station on cem.gov.vn 2.
What do the index levels mean?
| VN_AQI | Air quality | Colour | Advice for everyone | Advice for sensitive people |
|---|---|---|---|---|
| 0-50 | Good (Tốt) | green | outdoor activity freely | outdoor activity freely |
| 51-100 | Moderate (Trung bình) | yellow | outdoor activity freely | watch for cough or shortness of breath; outdoor activity still possible |
| 101-150 | Poor (Kém) | orange | if eyes hurt, cough or sore throat, consider less outdoor activity | cut strenuous activity and time outdoors; asthma medicine may be needed more often |
| 151-200 | Bad (Xấu) | red | cut strenuous outdoor activity, avoid long exercise, rest more indoors | stay indoors and cut strenuous activity; if you must go out, wear a proper mask |
| 201-300 | Very bad (Rất xấu) | purple | keep outdoor activity to a minimum and move it indoors; mask if you must go out | stay indoors and cut strenuous activity |
| 301-500 | Hazardous (Nguy hại) | brown | everyone stay indoors, doors and windows shut; mask if you must go out | same |
All levels and advice: Decision 1459/QĐ-TCMT 1. Sensitive people are older people, children and people with respiratory or heart disease 1.
How polluted is the air on average?
From satellite-based estimates, the population-weighted median of annual fine particles (PM2.5, 2021-2023) in Vietnamese cities is about 33 µg/m³ 3, more than six times the WHO guideline of 5 µg/m³ 4. It is a regional background: a busy street can be higher.
What should I do on a bad air day?
Follow the advice for your level above 1. Phaenyx found no national pollution alert system on an official source. See /guides/clean-air-room, /guides/masks-for-smoke and /guides/sensitive-people-polluted-air.
Frequently asked questions
What is a good AQI in Vietnam?
0 to 50 is good; 51 to 100 is moderate 1.
What does VN_AQI 200 mean?
151-200 is "bad": everyone should cut strenuous outdoor activity, and sensitive people should stay indoors 1.
Where is the official air quality data?
On cem.gov.vn, table "VN_AQI giờ" 2.
Preparedness index: Vietnam ranks joint 52nd of 67, 45.5/100 · full ranking
Sources · 4
- Tổng cục Môi trường (now Cục Môi trường), file hosted by Trung tâm quan trắc môi trường miền Bắc · Quyết định 1459/QĐ-TCMT ngày 12/11/2019 ban hành Hướng dẫn kỹ thuật tính toán và công bố chỉ số chất lượng không khí Việt Nam (VN_AQI) checked 2026-11-13
- Trung tâm quan trắc môi trường miền Bắc, Cục Môi trường (Bộ Nông nghiệp và Môi trường) · Trung tâm quan trắc môi trường miền Bắc (home page, VN_AQI giờ) checked 2026-11-13
- Atmospheric Composition Analysis Group (ACAG), Washington University in St. Louis · Surface PM2.5, V6.GL.02.04 (annual means 2021-2023) checked 2026-11-13
- World Health Organization · WHO global air quality guidelines (2021) checked 2026-11-13