Worst air pollution International Rose Test Garden - Portland, today and tomorrow
Today (9 August): Air quality in International Rose Test Garden is fair. AQI and O3 are fair; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 6:00 AM (O3: 37.5/100).
Tomorrow (10 August 2026): Air quality in International Rose Test Garden is fair. All pollutants stay as today. Pollution peaks around 8:00 AM (O3: 35.9/100). Airmine updates local air quality forecasts four times daily.
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Portland's International Rose Test Garden air quality benefits from the Washington Park's elevated hillside position at 150 metres, with the elevated position providing marginally better dispersal than the flat Willamette Valley floor below. The extraordinary 4.5-acre rose garden's open hillside position and the consistent Willamette Valley westerly winds provide natural ventilation, while summer wildfire smoke is the primary seasonal concern and the garden generally maintains good to moderate conditions throughout most non-wildfire periods.
Today - 9 August | Pollution peaks at 06:00
AQI:
Fair
37.5/100
PM2.5 (fine particles):
Good
7.7/100
PM10 (coarse particles):
Good
5.0/100
NO2 (nitrogen dioxide):
Good
13.0/100
O3 (ozone):
Fair
37.5/100
SO2 (sulfur dioxide):
Good
0.8/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
9.7/100
PM1 (ultrafine particles):
Good
5.3/100
Levels show the poorest local air quality during the day
Tomorrow - 10 August | Pollution peaks at 08:00
AQI:
Fair
35.9/100
PM2.5 (fine particles):
Good
9.9/100
PM10 (coarse particles):
Good
6.3/100
NO2 (nitrogen dioxide):
Good
16.2/100
O3 (ozone):
Fair
35.9/100
SO2 (sulfur dioxide):
Good
0.7/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
6.8/100
PM1 (ultrafine particles):
Good
7.6/100
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Frequently Asked Questions
Is air quality bad in International Rose Test Garden right now?
On 9 August 2026, overall air quality in International Rose Test Garden is fair. AQI is the main air quality indicator at 37.5/100. Pollution peaks around 6:00 AM (O3: 37.5/100).
Will air quality be worse tomorrow in International Rose Test Garden?
On 10 August 2026, air quality conditions in International Rose Test Garden will be similar to today, with AQI forecast at fair at 35.9/100. Pollution peaks around 8:00 AM (O3: 35.9/100).
When is air pollution at its worst in International Rose Test Garden?
Conditions at International Rose Test Garden vary noticeably across the seasons — the wet winter and spring months are generally the cleanest, with regular rain limiting particulate buildup, whereas 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 International Rose Test Garden 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: 10 August 2026 at 02:34 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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