Short answer. Check UK air quality and sign up for alerts on Defra's Check air quality service 1, or call 0800 556677 2. The Daily Air Quality Index (DAQI) runs from 1, low, to 10, very high, with forecasts up to 5 days ahead 2. On High or Very High days, try to reduce your exposure; people with heart or lung conditions and older people should adapt physically demanding outdoor activities 9.
Where can I check air quality right now?
On the government's Check air quality service: search a local area and sign up for air pollution alerts 1. Be Ready also gives a free phone line, 0800 556677 2. In Northern Ireland, DAERA's Northern Ireland Air site shows current levels and a five-day forecast, and its Air Aware service sends free SMS alerts to people with chronic conditions such as asthma or heart disease: text "Air" to 079 8440 5722 4.
What do the index levels mean?
The DAQI has four bands, each with a colour 8. Defra's health advice for each band 9:
| Band | Levels | Most people | Adults and children with heart or lung conditions |
|---|---|---|---|
| Low (green) | 1-3 | Continue your usual outdoor activities | Follow your doctor or nurse's usual advice about physically demanding activities and managing your condition |
| Moderate (yellow) | 4-6 | Continue your usual outdoor activities; if you have symptoms, try to reduce your exposure | Try to adapt physically demanding activities outdoors, especially if your symptoms get worse |
| High (red) | 7-9 | Try to reduce your exposure, especially if you have symptoms | Adapt physically demanding activities outdoors, especially if your symptoms get worse; older people too |
| Very High (purple) | 10 | Try to reduce your exposure, especially if you have symptoms | Adapt physically demanding activities outdoors, especially if your symptoms get worse; older people too |
The DAQI for a place is based on the highest level of five pollutants: PM2.5, PM10, nitrogen dioxide, ozone and sulphur dioxide 8. Use the highest level forecast for the day 2. The index is a daily index: it cannot be shown for shorter periods such as 3 hours 3. For other countries' scales, see what an air quality index means.
How polluted is the air on average?
Above the World Health Organization guidelines. The median UK city had about 8 µg/m³ of fine particles (PM2.5) a year in 2021-2023 5, against a WHO guideline of 5 7. For nitrogen dioxide, the regional background was about 14 µg/m³ 6, against a WHO guideline of 10 7. That NO2 figure is a regional background over roughly 80 km: a busy street is higher. Be Ready calls poor air quality "one of the greatest environmental risks to public health in the UK" 2.
What should I do on a bad air day?
Follow the band advice above 9. Be Ready adds 2:
- at high and very high levels, try to reduce your exposure, especially if you have symptoms;
- if you have a lung or heart condition, follow your agreed management plan, such as an asthma action plan, and ask your doctor or nurse for one if you have none;
- make sure family, friends and neighbours at higher risk know what to do;
- consult your vet about pets or livestock.
Speak to your doctor or nurse if you have new symptoms, if your symptoms get worse, or if they do not get better after a week 9. Our guides cover air pollution episodes, people most at risk, children, ozone days, wildfire smoke, masks for smoke and a clean-air room at home.
Frequently asked questions
What is a high DAQI in the UK?
7 to 9 is High and 10 is Very High 8.
Who is most at risk from air pollution?
People who live or work in areas of higher pollution, people with heart or lung conditions such as asthma, pregnant people, babies and children, and older adults 2.
Does the forecast show pollution on my street?
No. The Met Office forecast uses a 12 km grid and represents background air away from roads and city centres 3.
Can I get alerts by text?
In Northern Ireland, yes, through Air Aware 4. Elsewhere, the Check air quality service offers air pollution alerts 1.
A household plan can note who in your home is at risk and what to do on a High day.
Sources
- Department for Environment, Food & Rural Affairs (Defra) — Check air quality — https://check-air-quality.service.gov.uk/ (accessed 2026-10-27)
- Cabinet Office (GOV.UK Be Ready) — Poor air quality and pollution — https://beready.campaign.gov.uk/be-informed-about-hazards/poor-air-quality-and-pollution/ (accessed 2026-10-27)
- Met Office — Air pollution — https://www.metoffice.gov.uk/weather/guides/air-quality (accessed 2026-10-27)
- Department of Agriculture, Environment and Rural Affairs (DAERA) — Northern Ireland Air — https://www.airqualityni.co.uk/ (accessed 2026-10-27)
- Atmospheric Composition Analysis Group, Washington University in St. Louis — Surface PM2.5, V6.GL.02.04 (CC BY 4.0) — https://sites.wustl.edu/acag/datasets/surface-pm2-5/ (accessed 2026-10-27)
- Copernicus Atmosphere Monitoring Service — CAMS global reanalysis (EAC4) — https://ads.atmosphere.copernicus.eu/ (accessed 2026-10-27)
- World Health Organization — WHO global air quality guidelines (2021) — https://www.who.int/publications/i/item/9789240034228 (accessed 2026-10-27)
- Department for Environment, Food & Rural Affairs (Defra) — Using the Daily Air Quality Index (DAQI) — https://www.gov.uk/government/publications/health-effects-of-air-pollution/using-the-daily-air-quality-index-daqi (accessed 2026-10-27)
- Department for Environment, Food & Rural Affairs (Defra) — Health advice for the Daily Air Quality Index (DAQI) — https://www.gov.uk/government/publications/health-effects-of-air-pollution/health-advice-for-the-daily-air-quality-index-daqi (accessed 2026-10-27)
Turn this into action
Your plan for United Kingdom, worked out for your household.
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- The nuclear plants and zones around your home
- Phaenyx Safe: one tap to tell your people you are safe
Sources
- Department for Environment, Food & Rural Affairs (Defra) · Check air quality checked 2026-10-27
- Cabinet Office (GOV.UK Be Ready) · Poor air quality and pollution checked 2026-10-27
- Met Office · Air pollution checked 2026-10-27
- Department of Agriculture, Environment and Rural Affairs (DAERA) · Northern Ireland Air checked 2026-10-27
- Atmospheric Composition Analysis Group, Washington University in St. Louis · Surface PM2.5, V6.GL.02.04 (2021-2023 mean, median of UK cities) checked 2026-10-27
- Copernicus Atmosphere Monitoring Service · CAMS global reanalysis (EAC4), NO2 2021-2023 mean, median of UK cities checked 2026-10-27
- World Health Organization · WHO global air quality guidelines (2021) checked 2026-10-27
- Department for Environment, Food & Rural Affairs (Defra) · Using the Daily Air Quality Index (DAQI) checked 2026-10-27
- Department for Environment, Food & Rural Affairs (Defra) · Health advice for the Daily Air Quality Index (DAQI) checked 2026-10-27