Worst air pollution Downtown Sisters - Sisters, today and tomorrow
Today (9 August): Air quality in Downtown Sisters is fair. PM10 and PM1 are fair; AQI, PM2.5, NO2, and O3 are medium; SO2, CO, and HCHO are good. Pollution peaks around 12:00 AM (NO2: 58.0/100).
Tomorrow (10 August 2026): Air quality in Downtown Sisters is poor. AQI worsens to poor; PM2.5 increases to fair; NO2 increases to poor; O3 increases to fair; all other pollutants stay as today. Pollution peaks around 11:00 PM (NO2: 79.2/100). 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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Downtown Sisters, situated at the town's small Western-themed downtown beneath the Cascade peaks, sees the same seasonal air quality swings that shape the rest of Sisters. Any local variation tends to be minor compared with the seasonal swings seen across the wider city.
Today - 9 August | Pollution peaks at 00:00
AQI:
Medium
58.0/100
PM2.5 (fine particles):
Medium
41.1/100
PM10 (coarse particles):
Fair
30.0/100
NO2 (nitrogen dioxide):
Medium
58.0/100
O3 (ozone):
Medium
40.9/100
SO2 (sulfur dioxide):
Good
13.5/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
10.2/100
PM1 (ultrafine particles):
Fair
29.3/100
Levels show the poorest local air quality during the day
Tomorrow - 10 August | Pollution peaks at 23:00
AQI:
Poor
79.2/100
PM2.5 (fine particles):
Fair
32.6/100
PM10 (coarse particles):
Fair
22.3/100
NO2 (nitrogen dioxide):
Poor
79.2/100
O3 (ozone):
Fair
34.0/100
SO2 (sulfur dioxide):
Good
10.6/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
8.2/100
PM1 (ultrafine particles):
Fair
23.1/100
Other Landmarks in Sisters
Frequently Asked Questions
Is air quality bad in Downtown Sisters right now?
On 9 August 2026, overall air quality in Downtown Sisters is fair. PM10 is the main pollutant at 30.0/100. Pollution peaks around 12:00 AM (NO2: 58.0/100).
Will air quality be worse tomorrow in Downtown Sisters?
On 10 August 2026, air quality conditions in Downtown Sisters will be worse than today, with AQI forecast at poor at 79.2/100. Pollution peaks around 11:00 PM (NO2: 79.2/100).
When is air pollution at its worst in Downtown Sisters?
Conditions at Downtown Sisters vary noticeably across the seasons. Typically, the wet winter and spring months are generally the cleanest, with regular rain limiting particulate buildup, while the driest weeks of late summer bring the greatest risk of smoke drifting in from regional wildfires. Winter temperature inversions can briefly trap wood-smoke in low-lying valleys, but these episodes are usually short-lived.
Are air quality levels in Downtown Sisters 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: 9 August 2026 at 20:27 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.
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