Air Quality in South Portland, Maine — Live

Live readings from PurpleAir sensors across South Portland — with free alerts when the air quality index changes enough to matter.

Live South Portland AQI from nearby PurpleAir sensors loads when this page opens in a browser, along with a live sensor map covering South Portland and Portland, Cape Elizabeth, Scarborough, Westbrook.

South Portland's air is genuinely good most of the year. The city sits on the western edge of Casco Bay, and the sea breeze off the water tends to clear out whatever haze builds up on a hot afternoon. What makes South Portland's air story different from most New England towns isn't smoke - it's the working waterfront. More than 120 petroleum storage tanks line the shore here, part of the terminal that has fed the Portland-Montreal Pipe Line since 1941, and residents living near them have spent years asking state regulators a simple question: is the air actually safe to breathe.

Canairy watches the sensors around your home, your kids' school, and everywhere else you care about, and tells you in plain English when the air changes enough to matter.

South Portland's real air story is a tank farm, not a fire season

The waterfront terminal that anchors South Portland's economy stores crude oil in a cluster of tanks along the shore - more than 120 of them citywide - built to feed the 236-mile Portland-Montreal Pipe Line to Quebec refineries. Tank farms like this breathe: as oil moves in and out, volatile compounds including benzene and naphthalene can vent off, and for the neighborhoods closest to the shoreline that has been a documented concern for years, not a hypothetical one.

It came to a head in 2019. At an April 16 South Portland City Council workshop, residents said they were smelling odors from the petroleum storage facilities and wanted air monitoring inside city limits; Portland officials raised the identical complaint about the same facilities that August. Maine's Department of Environmental Protection agreed to help and stood up the South Portland/Portland VOC Monitoring Project, built specifically to measure the volatile organic compounds behind those odors and answer, in the agency's own words, whether the air is safe to breathe.

Why South Portland fought over tar sands instead of wildfire smoke

The same tank farm produced the city's biggest environmental fight of the last decade. After a 2013 ballot measure to block Canadian tar sands crude narrowly failed, the City Council passed a revised Clear Skies Ordinance in July 2014 banning the bulk loading of crude oil onto tankers at the waterfront terminal. The worry wasn't abstract: exporting heavier tar sands crude would have required heating the storage tanks to keep it liquid, meaning more emissions from a facility that already sat close to homes. The pipeline company spent roughly $650,000 fighting the ordinance in court; South Portland won the final round in 2021.

That fight is the opposite of the wildfire story that dominates air-quality pages for a lot of the country. There's no fire season to track here, and no smoke plume that blankets the whole city for a week. The exposure that worries South Portland residents is hyper-local - tied to specific streets near the tank farm, like Ferry Village and Knightville along Mill Creek - rather than a citywide event that reads the same for everyone.

The geography that keeps most days clear

South Portland sits low - about 59 feet at its highest point - on a small, flat peninsula bordered by Portland across the harbor, Cape Elizabeth and Scarborough to the south, and Westbrook inland to the west. There's no mountain ring or valley floor here to trap air the way it does in a lot of Western cities; Casco Bay's open water and onshore breeze do much of the work of clearing the air on their own. The Portland Jetport's main runway actually sits within South Portland's city limits - one more reminder that this is a working peninsula, not a quiet suburb.

Maine's environmental agency notes that ozone runs highest in the warmer months statewide and that fine-particle pollution can rise at any time of year, so summer is still worth watching even without a wildfire season. Because South Portland's real pollution risk is site-specific rather than citywide, a single official monitor miles away won't tell you much about the block you actually live on - which is the reason to check the sensor nearest your own street instead of one citywide number.

South Portland air quality FAQ

What is the air quality in South Portland right now?

This page shows the current AQI for South Portland, calculated from PurpleAir sensors across the city and updated continuously. The map below shows every live sensor, so you can check the reading closest to your own neighborhood.

Why does part of South Portland smell like petroleum?

South Portland's waterfront is home to more than 120 petroleum storage tanks feeding the Portland-Montreal Pipe Line, and volatile organic compounds like benzene and naphthalene can vent off them. After residents raised the issue at a 2019 City Council workshop, Maine's Department of Environmental Protection launched the South Portland/Portland VOC Monitoring Project to measure those emissions directly rather than rely on a single distant monitor.

What was South Portland's tar sands fight about?

In July 2014, the City Council passed the Clear Skies Ordinance banning the loading of crude oil onto tankers at the waterfront terminal, largely to stop the export of heavier Canadian tar sands crude. Processing that oil would have meant heating storage tanks near residential neighborhoods, raising the risk of more emissions - the pipeline company fought the ordinance in court for years before South Portland won in 2021.

What AQI level is unhealthy?

Under the US EPA scale, AQI 0-50 is Good and 51-100 is Moderate. From 101 the air is Unhealthy for Sensitive Groups - kids, older adults, and people with asthma or heart conditions - and above 150 it's Unhealthy for everyone. Canairy translates these numbers into a plain-English verdict, like whether to close the windows or move a workout indoors.

Where does Canairy's South Portland data come from?

Readings come from PurpleAir's network of laser particle sensors across South Portland and surrounding towns, cross-referenced with government monitors and the Google Air Quality API. You can see every sensor behind your numbers on the live map - there's no black box.

Is Canairy free?

Yes. The Canairy app is free to download and includes live air quality for all your saved places, plain-English verdicts, and free push alerts when the air crosses your threshold. A paid plan adds extras like SMS text alerts.

Get Canairy free on Google Play.