Portland Air Quality in 2024: Pollution Patterns
How air quality behaves in Portland: the latest measured AQI, which pollutants dominate, seasonal patterns, and the local drivers of pollution.
Current Air Quality
Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution.
Extra Protection for Portland Homes
Air quality in Portland is moderate (AQI 65), with fine particles (PM2.5) the main concern. A True-HEPA purifier gives sensitive groups — kids, seniors and anyone with asthma or allergies — cleaner air indoors on days like today.
Recommended: Levoit Vital 200S — True HEPA · washable pre-filter · rooms up to 1,875 sq ft
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Portland Air Quality in 2024
This page covers what shapes air quality in Portland over the course of a year: the pollutants that dominate locally, how conditions typically shift between seasons, and the local emission sources behind them. Measured 2024 annual statistics are published by EPA's Air Quality System, not here, so the AQI figure below is the latest observation available when this page was published.
View Current Portland Air Quality →Latest Measured Reading for Portland
The most recent EPA AirNow observation for the Southwest Coast reporting area puts Portland's AQI at 65 (Moderate), with fine particulate matter (PM2.5) as the dominant pollutant — typical for the Northeast region. Observed 6:00 AM EDT on August 9, 2026. Reported by Maine Dept. of Environmental Protection.
This is a single observation captured when the page was published, not a 2024 average. For measured annual and monthly statistics, use the EPA's Air Quality System reports.
How Portland Air Quality Shifts Through the Year
Mar–May: Usually Portland's cleanest stretch. Mild temperatures and better atmospheric mixing keep both ozone and particulates down.
Jun–Aug: Heat and sunlight drive higher ozone and, in the West, wildfire-smoke episodes. Afternoons are typically the worst time to be outside.
Sep–Nov: Air quality generally improves as temperatures drop, though early fall can still carry wildfire smoke in the Northeast region.
Dec–Feb: Cold-air temperature inversions can trap PM2.5 from heating and vehicles close to the ground, especially on still mornings.
Seasonal patterns above describe how pollution typically behaves in this region. They are not measured 2024 averages for Portland.
Is It Safe to Exercise Outside in Portland?
With Portland's AQI at 65 (Moderate), outdoor exercise is generally safe for most people. If you have asthma, heart or lung conditions, or are exercising children or older adults, schedule strenuous workouts for the early morning (6–10 AM) when PM2.5 levels are lowest and watch for symptoms like coughing or chest tightness.
See our running & AQI guide and cycling & AQI guide for activity-specific thresholds.
What's Causing Portland's Air Pollution?
In Portland, the leading pollutant is fine particulate matter (PM2.5). As part of the Northeast region, the main drivers of air pollution here are:
- •Dense urban vehicle traffic and congestion
- •Building heating systems burning oil and natural gas
- •Ozone and fine particulates transported from upwind states
- •Construction and demolition activity in growing metros
Dig deeper: Portland PM2.5 levels · Portland ozone levels
Air Purifier & Monitor Buying Guides
Not sure which device fits your needs? Our hands-on guides break down the best picks by use case.
PM2.5 Levels
Fine particulate matter data →
Ozone Levels
Ground-level ozone data →
Seasonal Guides
Air quality by season →
Health Effects
Learn about air pollution impacts →
Frequently Asked Questions About Portland Air Quality
What is the current air quality in Portland?
The current Air Quality Index (AQI) in Portland, ME is 65, which is considered moderate.
Is it safe to exercise outdoors in Portland?
Generally yes. With an AQI of 65, outdoor exercise is acceptable for most people. Sensitive individuals should monitor symptoms.
When is the best time of year to visit Portland for good air quality?
Spring and early fall typically offer the best air quality in Portland. Summer months may have elevated ozone levels, while winter can see higher PM2.5 from temperature inversions.
What causes air pollution in Portland?
Air pollution in Portland can come from vehicle emissions, industrial activity, construction, wildfires, and weather patterns. Local geography and seasonal factors also play a significant role.
Explore More Air Quality Data
Extra Protection for Portland Homes
Air quality in Portland is moderate (AQI 65), with fine particles (PM2.5) the main concern. A True-HEPA purifier gives sensitive groups — kids, seniors and anyone with asthma or allergies — cleaner air indoors on days like today.
Compare top-rated True-HEPA purifiers:
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