Worst air pollution Welwyn Garden City, today and tomorrow
Today (16 July): Air quality in Welwyn Garden City is fair. AQI and O3 are fair; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 4:00 PM (O3: 31.6/100).
Tomorrow (17 July 2026): Air quality in Welwyn Garden City is fair. All pollutants stay as today. Pollution peaks around 3:00 PM (O3: 37.8/100). Airmine updates local air quality forecasts four times daily.
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Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
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Welwyn Garden City's position in Hertfordshire means air quality is mostly determined by local road traffic and the compact scale of the centre. Residential heating and light industry add a modest seasonal contribution, though moist Atlantic fronts keep overall levels moderate. Rush-hour queues near the A46 are usually when readings climb the most.
Today - 16 July | Pollution peaks at 16:00
AQI:
Fair
31.6/100
PM2.5 (fine particles):
Good
6.8/100
PM10 (coarse particles):
Good
2.4/100
NO2 (nitrogen dioxide):
Good
2.9/100
O3 (ozone):
Fair
31.6/100
SO2 (sulfur dioxide):
Good
0.5/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
2.8/100
PM1 (ultrafine particles):
Good
6.0/100
Levels show the poorest local air quality during the day
Tomorrow - 17 July | Pollution peaks at 15:00
AQI:
Fair
37.8/100
PM2.5 (fine particles):
Good
10.5/100
PM10 (coarse particles):
Good
3.6/100
NO2 (nitrogen dioxide):
Good
3.9/100
O3 (ozone):
Fair
37.8/100
SO2 (sulfur dioxide):
Good
0.8/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
4.0/100
PM1 (ultrafine particles):
Good
9.3/100
Pollen forecast in Welwyn Garden City
View pollen forecastFrequently Asked Questions
Is air quality bad in Welwyn Garden City right now?
On 16 July 2026, overall air quality in Welwyn Garden City is fair. AQI is the main air quality indicator at 31.6/100. Pollution peaks around 4:00 PM (O3: 31.6/100).
Will air quality be worse tomorrow in Welwyn Garden City?
On 17 July 2026, air quality conditions in Welwyn Garden City will be similar to today, with AQI forecast at fair at 37.8/100. Pollution peaks around 3:00 PM (O3: 37.8/100).
When is air pollution at its worst in Welwyn Garden City?
Air quality in Welwyn Garden City isn't the same all year round — it really shifts with the seasons. Winter mornings can be the trickiest, with cold, still conditions trapping A46 traffic fumes and smoke from home fires close to the ground. Summer brings a different issue — stronger sunlight can push up ozone levels on hot, sunny days, even though traffic pollution itself often disperses more easily.
Are air quality levels in Welwyn Garden City based on measurements or forecasts?
It is forecasts derived by downscaling forecasts provided by EU’s Copernicus Atmosphere Monitoring Service (CAMS) by taking into account local conditions such as traffic patterns. CAMS bases its forecast on satellite measurements of particles and chemical compounds in the atmosphere. Airmine’s services were developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team.
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Data provided by Airmine — Last update: 16 July 2026 at 10:33 CEST (Data is updated four times daily.)
This forecast is produced independently using Airmine's own atmospheric data and models.
Unless explicitly made clear, the content on this site has not been paid for by external organisations and is Airmine's sole responsibility.
For long term forecasts and maps, see the Airmine app