MUSCATINE, Iowa — November was a bad month for air quality in Muscatine — at least when it came to sulfur dioxide.

As measured by the Iowa Department of Natural Resources’ Ambient Air Monitoring Group, the air quality index for Nov. 10 was off the charts.

The DNR’s measurement at a monitoring station in Musser Park that day showed 308.8 parts per billion for sulfur dioxide, or SO2, which works out to an air-quality index of more than 200.

That’s such a large measurement that the DNR said an air quality index is not defined for one-hour SO2 values greater than 304 parts per billion, or an air-quality index of 200.

The exceedence level for SO2 is 75.5 parts per billion, according to the National Ambient Air Quality Standards.

According to the Centers for Disease Control and Prevention website, sulfur dioxide in the air results primarily from activities associated with the burning of fossil fuels such as coal and oil at power plants or from copper smelting.

Possible health effects include breathing difficulties and burning in the nose and throat.

Jessica Brackett, executive director of Clean Air Muscatine, or CLAM, said that federal and state air quality monitoring agencies — the federal Environmental Protection Agency and the DNR — are working with area businesses and utilities in an effort to improve Muscatine’s air quality. The EPA has set a February 2013 deadline for the DNR to develop a plan for reducing air pollution in Iowa.

Through Nov. 22, Muscatine exceeded National Ambient Air Quality Standards 35 times, virtually all the result of SO2 measurements.

In 2011 — the record year for exceedences — Muscatine exceeded the standards 36 times.

Muscatine had not experienced a PM2.5 exceedence (the smaller version of particulate matter, which can penetrate deep into the lungs) since April 29, which was before the countywide system was put in place.

“I check those, and I haven’t received any for Muscatine County since April,” Kelly said.

In April, CLAM held a workshop to help residents establish what’s called a Bucket Brigade, which uses homemade instruments to help generate data about which toxins are present in the air and, according to a CLAM media release, “gain a broader understanding of Muscatine air quality.”

Seven particle air samples throughout Muscatine and neighboring counties have been taken to date, Brackett said. Samples were analyzed for small particles.

Mark Chernaik, a staff scientist with Environmental Law Alliance Worldwide, an Oregon-based public interest group, said this of the Bucket Brigade testing: “The average air quality of the dataset exceeds both the U.S. EPA National Ambient Air Quality Standard and the World Health Organization’s annual air quality standards to PM2.5.”

“Our community has been promised air quality will improve,” Brackett said. “Testing done by Clean Air Muscatine shows additional pollutants that have not previously been brought to the attention of our community, and Iowa DNR testing shows this year’s exceedences have nearly reached the record high set in 2011.”