Cherokee Chronicle Times

Northwest Iowa air quality unhealthy for some

Wildfire smoke from Canada


Air quality in Northwest Iowa became unhealthy for sensitive groups over the past month because of Canadian wildfire smoke that drifted into the Midwest.  

The Iowa Department of Natural Resources reported “exceedances” of the National Ambient Air Quality Standard (NAAQS) for ozone at two sites in Northwest Iowa and six sites across Iowa last week. NAAQS is essentially a measurement of air quality against public health standards.

Air quality in Buena Vista and Cherokee counties exceeded the NAAQS for five out of the last 14 days, according to a review of DNR air quality monitoring data. 

“Smoke from the fires has been evident across much of the state recently and elevated particulate and ozone levels may be a concern over the next several days,” reads a statement released last Wednesday by the DNR, which encouraged vulnerable populations to limit outdoor activity. 

Air quality conditions were ripe for ozone formation, a series of chemical reactions that create a smog-like haze that irritates respiratory systems. Ozone, one of six pollutants in the NAAQS, is especially harmful to asthmatics, those with respiratory difficulties or heart disease, the elderly, children and pregnant women, according to the DNR. Todd Russell, a DNR official in the state agency’s ambient air quality monitoring bureau, acknowledged the month of May in Iowa is a “tough month” for air quality because wind speeds decrease, temperatures increase and crop cover isn’t sufficient to “scrub the ozone out of the air.” Essentially sunlight and heat catalyze ground-level ozone formation. 

“It’s not terribly unusual we see elevated (pollution),” Russell said. “But I really think the primary difference at this point would be the (wildfire) smoke.”

⇒ MORE: Iowa Air Quality Index

Ozone levels in Northwest Iowa spiked when the fires started raging earlier this month. A haze became visible over the Storm Lake area May 18; the air quality index for Northwest Iowa on that day registered 107, meaning the ozone levels exceeded the NAAQS by at least one part per billion. At such levels, at-risk groups are recommended to limit outdoor activity. 

The fires are still raging. Canada is in the midst of a mega fire season, with many months to go. The Washington Post reported five million acres have been scorched so far this year, not far from the annual average of 6 million scorched acres. But this year’s total has already surpassed totals from many previous years, and the fires are more widespread. Blazes have been reported all across the country. Temperatures are running three to five degrees above average. 

“In the last week are two, there’s fires going on all over Northern Alberta, Saskatchewan, even in the Northwest Territories,” said Russell when asked about the source of the haze. “And that’s primarily where they’re (from).”

Russell noted there is no way to estimate the scope of pollution that was blown into the Midwest, but the air quality index at most locations in Iowa have doubled since May 18. The day before, the index registered a score of 58, as analyzed by the Emmetsburg air quality monitor. 

The DNR’s prediction models show the area returning to “moderate” levels of pollution, or an air quality index score between 50 to 100. 

The DNR’s estimated ozone pollution levels in Buena Vista and Cherokee counties are believed to be accurate, despite a lack of monitoring equipment in the area. Researchers at the University of Iowa have said Northwest Iowa lies in “no man’s land” in terms of air quality monitoring because there are only two monitors: Emmetsburg and a forest area in Pisgah that measures upwind pollution from the Omaha metropolitan area. DNR officials have cited high operating costs as the reason why there are no monitors in Northwest Iowa outside of Emmetsburg. Russell asserted the ozone data measured by the Emmetsburg monitor reflects ozone levels in Buena Vista and Cherokee Counties because ozone is a “regional pollutant.”

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