Worst air pollution Letchworth Garden City, today and tomorrow
Today (16 July): Air quality in Letchworth 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 Letchworth 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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Commuter traffic feeding onto the A303 adds a further, consistent contribution to local readings. Letchworth Garden City sits within Hertfordshire, and its air quality profile is driven mainly by road traffic and the density of the centre. Light prevailing breezes offer a degree of natural ventilation, keeping pollution broadly in line with comparable UK towns.
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
2.7/100
O3 (ozone):
Fair
31.6/100
SO2 (sulfur dioxide):
Good
0.4/100
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
10.4/100
PM10 (coarse particles):
Good
3.6/100
NO2 (nitrogen dioxide):
Good
3.6/100
O3 (ozone):
Fair
37.8/100
SO2 (sulfur dioxide):
Good
0.7/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
4.0/100
PM1 (ultrafine particles):
Good
9.3/100
Pollen forecast in Letchworth Garden City
View pollen forecastFrequently Asked Questions
Is air quality bad in Letchworth Garden City right now?
On 16 July 2026, overall air quality in Letchworth 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 Letchworth Garden City?
On 17 July 2026, air quality conditions in Letchworth 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 Letchworth Garden City?
You can roughly predict Letchworth Garden City's air quality just by knowing the time of year. The coldest months usually bring the worst readings, as heating and temperature inversions keep A303 emissions from dispersing normally. In summer, ozone can build up on sunny afternoons, though windier, warmer weather usually helps clear traffic-related pollution faster than in winter. The shoulder seasons generally bring the mildest readings of the year.
Are air quality levels in Letchworth 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