Current Air Quality Data

The Air Quality Index (AQI) information below reflects the rolling average at each site. Since Ozone has an 8-hour health standard the rolling average is the average of the current hour and the preceding 7 hours. Particle Pollution has a 24-hour health standard; therefore the rolling average is the average of the current hour and the preceding 23 hours. Select a monitoring station from the tables or a region on the map to view detailed ozone or particle pollution data. This is "preliminary" data, which means some of the values may change after they undergo additional quality assurance reviews during the next several weeks, before being reported as "final" data to the EPA. More about interpreting the data

Special status notes:

Cold Weather Statement for Particle Pollution: 1) At this time of year clear nights with little or no wind can allow capping of pollutants near the ground (called a nocturnal inversion). If there is also little vertical mixing during the day Particle Pollution levels will likely remain high long enough that the average for the day is Moderate. Urban areas and Valleys are most prone to these higher levels of pollutants. If you have a heart or lung disease you will want to check the forecast nearly every day through the winter months. 2) Coarse particles are a problem during high traffic times near roadways that have dried out after being heavily sanded.

NOTES: Ozone and Particle pollution data can also be viewed on Google Earth from data and forecasts ME DEP submits to EPA’s AIRNOW program. Data is displayed using AQI color categories to represent the highest of either ozone or particle pollution for current data and the forecast. Some sites in Maine are run by other entities who submit their data directly to AIRNOW so this tool allows you to view that data along with the ME DEP data.

Air Monitoring Stations

Northern Region
Location	Pollutant	Air Quality
Ashland	Ozone	Good
Greenville	Particle	Good

Western Mtns Region
Location	Pollutant	Air Quality
Lovell	Ozone	Closed

Western Interior Region
Location	Pollutant	Air Quality
Durham	Ozone	Closed
Gardiner	Ozone	Closed
Lewiston	Particle	Good
Shapleigh Ball Park	Ozone	Closed
West Buxton	Ozone	Good

Eastern Interior Region
Location	Pollutant	Air Quality
Bangor	Particle	Good
Holden	Ozone	Closed
Penobscot Nation	Ozone	Good

Southwest Coast Region
Location	Pollutant	Air Quality
Bowdoinham	Ozone	Closed
Cape Elizabeth	Ozone	Closed
Kennebunkport	Ozone	Closed
Portland Deering Oaks	Particle	Good

Mid-Coast Region
Location	Pollutant	Air Quality
McFarland Hill	Ozone	Good
McFarland Hill	Particle	Good
Port Clyde	Ozone	Closed

Downeast Region
Location	Pollutant	Air Quality
Jonesport	Ozone	Closed
Sipayik (Pleasant Point - Passamaquoddy	Ozone	Good

High Elevation Region
Location	Pollutant	Air Quality
Cadillac	Ozone	Closed

Map of Maine displaying the various air quality regions and the monitoring stations contained within.

Interpreting the data

See Air Quality Index for more information regarding Air Quality Index values.

This page is scheduled to be updated hourly. The updates should appear within a few minutes after the half-hour mark. It's always a good idea to check the "last update time."

We also provide the unedited hourly concentrations. This is Raw data which has not been converted to the Air Quality Index. Ozone values are reported in parts per billion (ppb). Particle pollution values are reported in micrograms per cubic meter (µg/m³).

The hourly pollutant values, shown in the graphs, are based on the national Air Quality Index (AQI). The AQI is computed from data collected by a network of air monitoring sites. The AQI converts the pollutant concentrations to a value easily compared to the health standard of each pollutant.

8-hour Ozone and 24-hour Particle Pollution concentrations with an AQI over 100 have exceeded the health standard.

The color-coding is based on the AQI. Green indicates values in the "good" range; yellow in the "moderate" range; orange in the "unhealthy for sensitive groups" range; red in the "unhealthy" range, and purple in the "very unhealthy" range. An X indicates suspect data.

Please note that Maine Air Quality Forecasters issue PM2.5 forecasts for a 24-hour (midnight to midnight) block. Therefore, the current rolling average may be higher than the midnight to midnight AQI value. This often occurs when particle values climb late one day and decrease early the next. The midnight to midnight AQI for both days may be Good even though several rolling averages reached the Moderate level. When Maine's Air Quality Forecasters believe this is likely to happen, it will often be included in the forecast details section of the Air Quality Forecast page.