This page lists the 2005 season daily peak 8-hour-averaged ozone concentrations at MassDEP monitors across Massachusetts, colored according to health-based Air Quality Index categories (see Ozone Health Guidelines for an explanation of the colors). Values shown are preliminary. Quality assurance checks may, for a small number of values, result in slight changes.

Ozone concentrations are reported in parts per billion (PPB). For example, a concentration of 38 means there was an average of 38 parts of ozone for every billion parts of air on that day at that location. "M" denotes that data is missing for that day at that location because of equipment or network problems, or a newly installed monitor not being operational yet.

Monthly Ozone Data

May 2005
MS Excel 20 KB | PDF 13 KB

June 2005
MS Excel 19 KB | PDF 13 KB

July 2005
MS Excel 18 KB | PDF 13 KB

August 2005
MS Excel 18 KB | PDF 13 KB

September 2005
MS Excel 19 KB | PDF 13 KB