Worst air pollution Llanrwst, today and tomorrow
Today (20 September): Air quality in Llanrwst is good. AQI, PM2.5, PM10, NO2, O3, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 9:00 AM (PM10: 18.0/100).
Tomorrow (21 September 2026): Air quality in Llanrwst is fair. AQI worsens to fair; NO2 increases to fair; PM1 increases to fair; all other pollutants stay as today. Pollution peaks around 9:00 AM (NO2: 23.0/100). Airmine updates local air quality forecasts four times daily.
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Llanrwst sits within Conwy, and its air quality profile is driven mainly by road traffic and the density of the centre. Residential heating and light industry add a modest seasonal contribution, though inland breezes from the surrounding countryside keep overall levels moderate. The M4 sees the heaviest traffic, and that shows up clearly in local roadside monitoring.
Today - 20 September | Pollution peaks at 09:00
AQI:
Good
18.0/100
PM2.5 (fine particles):
Good
16.7/100
PM10 (coarse particles):
Good
18.0/100
NO2 (nitrogen dioxide):
Good
11.3/100
O3 (ozone):
Good
16.5/100
SO2 (sulfur dioxide):
Good
1.2/100
CO (carbon monoxide):
Good
0.7/100
HCHO (formaldehyde):
Good
2.8/100
PM1 (ultrafine particles):
Good
12.0/100
Levels show the poorest local air quality during the day
Tomorrow - 21 September | Pollution peaks at 09:00
AQI:
Fair
23.0/100
PM2.5 (fine particles):
Good
19.1/100
PM10 (coarse particles):
Good
18.2/100
NO2 (nitrogen dioxide):
Fair
23.0/100
O3 (ozone):
Good
18.2/100
SO2 (sulfur dioxide):
Good
1.9/100
CO (carbon monoxide):
Good
0.7/100
HCHO (formaldehyde):
Good
4.4/100
PM1 (ultrafine particles):
Fair
21.9/100
Pollen forecast in Llanrwst
View pollen forecastFrequently Asked Questions
Is air quality bad in Llanrwst right now?
On 20 September 2026, overall air quality in Llanrwst is good. AQI is the main air quality indicator at 18.0/100. Pollution peaks around 9:00 AM (PM10: 18.0/100).
Will air quality be worse tomorrow in Llanrwst?
On 21 September 2026, air quality conditions in Llanrwst will be worse than today, with AQI forecast at fair at 23.0/100. Pollution peaks around 9:00 AM (NO2: 23.0/100).
When is air pollution at its worst in Llanrwst?
Ask a local in Llanrwst and they'll tell you air quality changes noticeably from season to season. Winter mornings can be the trickiest, with cold, still conditions trapping M4 traffic fumes and smoke from home fires close to the ground. Come summer, it's ozone rather than particulates that's the bigger concern, especially on still, sunny days. Most of spring and autumn stays fairly steady, right in the middle of those two extremes.
Are air quality levels in Llanrwst 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.
Why doesn’t the forecast always reflect wildfire impacts?
Airmine’s forecast uses CAMS (Copernicus Atmosphere Monitoring Service) as its background atmospheric model. While CAMS includes wildfire emissions, these are derived from satellite observations and are not available in real time. During rapidly evolving wildfire events, there may therefore be a delay before increased emissions are incorporated into the model. As a result, the forecast may temporarily underestimate PM₂.₅ and other pollutants associated with wildfire smoke.
During rapidly evolving wildfire events, CAMS may lag by approximately 1–2 days before increased wildfire emissions are fully represented, which can lead to temporary underestimation of PM₂.₅ concentrations in Airmine’s forecast.
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Data provided by Airmine — Last update: 20 September 2026 at 14:33 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.
Disclaimer: Forecasts are provided for informational purposes only and should not be relied upon as medical advice. Actual pollen and air quality conditions may vary from the forecast. If you have allergies, asthma, or another medical condition, consult a healthcare professional. Please see our Terms of Service for important information about limitations of liability.
Some text on this page may be generated or summarised using artificial intelligence (AI). Wherever possible, AI-generated content is enriched with Airmine's proprietary data to improve its accuracy and relevance. However, AI-generated content may still contain errors, omissions, or inaccuracies.
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