Worst air pollution St. Johns - Portland, today and tomorrow
Today (15 July): Air quality in St. Johns is medium. AQI and O3 are medium; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 7:00 AM (O3: 41.5/100).
Tomorrow (16 July 2026): Air quality in St. Johns is fair. AQI worsens to fair; O3 increases to fair; all other pollutants stay as today. Pollution peaks around 4:00 AM (O3: 36.7/100). Airmine updates local air quality forecasts four times daily.
For long term forecasts and maps, see the Airmine app
Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
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Portland's St. Johns air quality reflects the North Portland neighbourhood adjacent to the St. Johns Bridge and the Columbia River industrial corridor, with vehicle traffic on N Lombard Street and the surrounding industrial legacy and residential character contributing local sources. The Columbia River provides limited ventilation, while the surrounding industrial corridor's background emissions and the neighbourhood's working-class character maintain moderate to above-average North Portland readings throughout most of the year.
Today - 15 July | Pollution peaks at 07:00
AQI:
Medium
41.5/100
PM2.5 (fine particles):
Good
5.6/100
PM10 (coarse particles):
Good
2.9/100
NO2 (nitrogen dioxide):
Good
7.2/100
O3 (ozone):
Medium
41.5/100
SO2 (sulfur dioxide):
Good
0.7/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
6.5/100
PM1 (ultrafine particles):
Good
4.6/100
Levels show the poorest local air quality during the day
Tomorrow - 16 July | Pollution peaks at 04:00
AQI:
Fair
36.7/100
PM2.5 (fine particles):
Good
5.2/100
PM10 (coarse particles):
Good
2.0/100
NO2 (nitrogen dioxide):
Good
3.4/100
O3 (ozone):
Fair
36.7/100
SO2 (sulfur dioxide):
Good
0.7/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
5.0/100
PM1 (ultrafine particles):
Good
4.9/100
Other Landmarks in Portland
Frequently Asked Questions
Is air quality bad in St. Johns right now?
On 15 July 2026, overall air quality in St. Johns is medium. AQI is the main air quality indicator at 41.5/100. Pollution peaks around 7:00 AM (O3: 41.5/100).
Will air quality be worse tomorrow in St. Johns?
On 16 July 2026, air quality conditions in St. Johns will be worse than today, with AQI forecast at fair at 36.7/100. Pollution peaks around 4:00 AM (O3: 36.7/100).
When is air pollution at its worst in St. Johns?
This neighborhood in Portland sees air quality shift through the year: spring is often the freshest stretch, sandwiched between winter rain and summer fire season, but by late summer, wildfire smoke can override the region's usual clean-air advantage for days at a time. Coastal areas see relatively little of the smoke that can settle into inland valleys during fire season.
Are air quality levels in St. Johns 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