What is the air quality trend in Portland?

Over the past 15 days, Portland had an average AQI of 28 based on station measurements. The worst day was 2026-05-18 with AQI 44.

How is Portland air quality measured?

Air quality in Portland is measured by ground-level monitoring stations that report PM2.5 and PM10 concentrations hourly. CERNS.IO aggregates readings from nearby stations and converts PM2.5 to the US EPA Air Quality Index (AQI) scale.

Air Quality History for Portland, United States

Name: Portland Air Quality History
Creator: CERNS.IO
License: https://creativecommons.org/licenses/by/4.0/

Historical PM2.5 and AQI trend from monitoring stations near Portland, United States.

Current AQI
Good CAMS model

48 Hours 7 Days 14 Days 20 Days

CSV JSON

Air Quality Index Station

201h

PM2.5 Station

201h · 1 station

Temperature GFS model

56pt

Precipitation GFS model

mm/day

Daily Summary Station

Date	AQI	Range	PM2.5 avg	Hours	Stations
2026-05-30	26	7–42	6.4 µg/m³	5h	1
2026-05-29	33	8–65	8.1 µg/m³	14h	1
2026-05-28	26	11–51	6.3 µg/m³	16h	1
2026-05-27	26	9–40	6.3 µg/m³	14h	1
2026-05-26	20	7–35	4.8 µg/m³	13h	1
2026-05-25	26	6–58	6.4 µg/m³	14h	1
2026-05-24	20	8–33	4.7 µg/m³	13h	1
2026-05-23	22	8–31	5.1 µg/m³	17h	1
2026-05-22	23	14–45	5.5 µg/m³	15h	1
2026-05-21	29	4–52	7.0 µg/m³	17h	1
2026-05-20	34	11–46	8.1 µg/m³	10h	1
2026-05-19	30	10–61	7.4 µg/m³	15h	1
2026-05-18	44	17–90	11.4 µg/m³	17h	1
2026-05-17	43	23–56	10.4 µg/m³	14h	1
2026-05-16	19	2–43	4.6 µg/m³	7h	1

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