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NOTE: The levels for each pollutant in the graphs, tables, and downloadable files from this page are the MAX value for a given day. To find the average values go to the Trends by Pollutant tab. This does not apply to the 24 and 48 hour graphs, which show the value for each hour.
- - - - this line is the Federal Standard (or if showing AQI, the level Unhealthy for Sensitive Subgroups)
Show AQI - click box to display different pollutants in common units of the Air Quality Index (AQI).

Data Disclaimer -- raw vs. final data
Download options explained and graph FAQs

Download Air Monitoring Data

You can download recent raw (unvalidated) air monitoring data by using the graphing tool above to select the data and then selecting one of the download format buttons beneath the graph. This data, however, has NOT been through any quality assurance review and is NOT final valid data. In addition, the hourly data available through the graphing tool is only available for the past 48 hours - older data is in summary form only.

Validated Data - MassDEP submits its final validated air monitoring data to EPA's AQS database. EPA provides a query tool where you can download data from MassDEP and other states, territories, or tribes that perform air monitoring: EPA Air Data - Download Data This is part of EPA's Air Data website. Instructions for using EPA's query tool are available at that site.

Although EPA's AQS website calls the data "raw" the Massachusetts air monitoring data in AQS has gone through quality assurance review by MassDEP air monitoring staff. Because this review takes about 3 months, the data in AQS is not the most recent. If you need the most recent data available (or have another type of special data request), please contact MassDEP's Air Assessment Branch at: Ann.Sorensen@MassMail.State.MA.US

Long-term Trends by Pollutant

MassDEP has monitored some pollutants for more than 20 years. You can find summaries of long-term historic data at the following links and in the Annual Air Quality Reports.