A new study examining pollution levels across a 16-year span found that while general pollution levels from sources such as cars and industry have significantly declined, recent increases in wildfire smoke air pollution have offset those gains and could be contributing to negative outcomes for pregnant women and babies such as low birth weight and preterm births.  

Published by Frontiers in Environmental Health, the study included data from about 64.5 million pregnancies between 2003 and 2019, covering more than 2,800 counties in 48 states. Even in regions that are not strongly associated with wildfire, such as the southeast region of the U.S., wildfire pollution rates grew substantially during that time period. The study did not account for any movement between counties or regions during pregnancy, or whether pregnant people used any protection against smoke such as masks, air filters or temporary relocation.

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Wildfire pollution is included in the same type of pollution as exhaust from cars or industrial outputs, but the study authors looked at two models of pollutants, one of which removed all fire-related pollution to determine how much of it was correlated with wildfire. Over the study period, about 65% of the days that recorded pollution levels above the National Ambient Air Quality Standard could be attributed to wildfire smoke.

Menglu Liang, leading author of the study and assistant clinical professor of biostatistics at the University of Maryland, said in a news release that efforts to reduce other forms of pollution have not been in vain.

“Those gains have genuinely protected pregnant people and unborn babies, and without them, exposures today would be considerably worse,” Liang said. “What our findings show is that wildfire smoke is offsetting a growing share of these hard-won improvements.”

The study time period does not include some of the most recent, most explosive wildfire seasons in the United States and Canada, such as 2020, 2024 and this year. By mid-July this year, there were more than 800 wildfires burning across Canada, leading to hazardous levels of wildfire smoke across parts of the Midwest and northeast, and in late July, a rash of wildfires across Oregon created hazardous air over much of the northwest. 

Recent reports show Oregon is on track to have its worst fire season on record, with nearly 1.8 million acres already burned and at least two months left of the peak season. The previous record was set in 2024, with 1.9 million acres burned.

The study found that some regions were disproportionately affected by the smoke, including in the Northwest, where rates of pollution from wildfire more than doubled over that period. The study noted that the burdens were highest in low-income, rural areas with significant populations of American Indian and Alaska Native communities, and areas with maternity care shortages.

 Recent studies have correlated wildfire smoke exposure with an increased risk of preterm birth, low birth weight and other negative outcomes such as stillbirth and some congenital anomalies. Scientists believe the body’s inflammatory responses to wildfire smoke can be harmful to the placenta, which is central to fetal survival, and some of the pollutants could cross the placental barrier and affect fetal growth and development.

“These outcomes matter well beyond the delivery room and harms experienced before birth can echo for decades,” Liang said in the release. “That makes prenatal exposure a particular public health concern.”

Stateline reporter Kelcie Moseley-Morris can be reached at kmoseley@stateline.org.

For the second time in three years, noxious clouds of wildfire smoke are smothering Wisconsin, dangerously degrading air quality and restricting people’s ability to go outside. In Madison, smoke began drifting in during the early morning hours on Thursday. By sunrise, the stench of burning forests had settled in and coated the Badger State’s capitol city in a gray smog, compounding a multi-day heatwave bringing temperatures to nearly 100 degrees Fahrenheit.

The smoke originated from 17 wildfires in the Superior National Forest caused by lightning strikes in far northeastern Minnesota. Severe drought and heat fueled the fires, threatening a 1.1 million acre forest that is the most visited wilderness area in the U.S. Rangers are searching for 6,000 to 10,000 people who might be in an area that has been evacuated because of the fires, PBS reported. Officials have cancelled all Boundary Water canoe permits, and closed public access to the Boundary Waters Canoe Area Wilderness as part of a 3.9 million acre closure covering the entire Superior National Forest.

In Wisconsin, the fallout has been far-reaching. A statewide air quality advisory has been issued by the Department of Natural Resources (DNR), with the air expected to remain unhealthy until at least Friday. 

Local health departments from Milwaukee to Kenosha are warning residents to avoid the outdoors as much as possible, especially children, older people, pregnant women and those with respiratory ailments like asthma and heart disease. Even healthy people may experience eye irritation, coughing, sore throats or shortness of breath due to exposure to the smoke. 

“While breathing problems and respiratory health dangers are often considered the biggest health impact from wildfire smoke, it’s important to recognize the impact on cardiovascular health as well,” said Dr. Art Coffey, a board member of the Milwaukee American Heart Association and a ProHealth Care cardiologist. “Wildfire smoke contains a lot of pollutants including fine, microscopic particles linked to cardiovascular risk. As these fires continue to burn, that contaminated smoke is traveling many miles beyond the immediately affected area.” 

A press release from the American Heart Association warns that smoke exposure can increase the risk of sudden cardiac arrest and increase burdens on local emergency services. One study in the Journal of the American Heart Association found that heavy wildfire smoke exposure increased the risk of out-of-hospital cardiac arrests by 70%, with that risk elevated among both men and women, particularly in adults from 35-64 years of age and those in high-poverty communities.

In a new analysis, the environmental advocacy group Clean Wisconsin estimated that 250 premature deaths occur each year in Wisconsin due to wildfire smoke exposure. The environmental group warns that these trends are likely to worsen. From 2010 to 2020, Clean Wisconsin stated, wildfire smoke caused unhealthy air quality conditions in the state for less than one day per year. Since 2020, however, wildfire smoke has caused unhealthy air in Wisconsin for an average of nine days per year. The smoke also carries particulate matter which is so small that it can penetrate the lungs deeply and cross into the blood stream, potentially leading to heart disease, cancer, dementia, blood clots, stroke and early death.

Milwaukee’s health and public works departments have suspended or modified some services. Garbage and recycling collection is suspended until further notice, and the city’s drop-off centers are also closed. The city tow lot closed Thursday afternoon. Air quality in the Milwaukee area is considered dangerous, and people are advised to stay inside, run air conditioning, use portable air cleaners or air filters, wear N95 masks or similar protection if they have to go outside, and to check on their neighbors and loved ones. 

Milwaukee County Executive David Crowley  said in a statement that this has become “the worst air quality on record for our community,” adding, “I encourage everyone to take this situation seriously, limit time outdoors when possible, and follow guidance from public health officials.”

All beer gardens, splash pads, outdoor and indoor pools and wading pools have closed in Milwaukee County parks. Residents rely on some of these services to cope with the high temperatures, but the smoke makes their continued operation unsafe. The Milwaukee County Zoo has also had to move some animals inside and cancel attractions and programming.

The Irwin A. and Robert D. Goodman Pool in Madison in Madison is also closed. In Kenosha, two park pools have closed as well as a municipal golf course, bulk and recycling and compost drop-off sites. A local “Peanut Butter & Jam concert” has also been canceled until further notice.

Climate change, the elephant trumpeting in the room

Experts and advocates stress the connection between repeated wildfire smoke emergencies and climate change, which creates the heatwaves and extreme drought conditions which set the stage for massive blazes.

“Increasingly smoky skies underscore the importance of a rapid transition to clean energy rather than building more polluting fossil fuel infrastructure that further contributes to climate change,” Dr. Paul Matthewson, science program director for Clean Wisconsin, said in a statement. “The faster we can reduce our greenhouse gas emissions and slow climate change, the more summer days we will be able to enjoy outside without worrying about whether the air is safe to breathe.” 

“The wildfire smoke blanketing Wisconsin is a reminder that climate change is not a distant threat,” said Peg Shaeffer, spokesperson for Midwest Environmental Advocates. “It is already harming public health and disrupting our daily lives. While no single fire can be attributed solely to climate change, we know that a warming climate is making large wildfires more frequent and more severe.”

Chelsea Chandler, Clean Wisconsin’s climate, energy and air program director, said, “This is hurting everybody — our kids on the playground, farmers, construction workers.” Chandler added, “The public health threat we are all enduring must be a wakeup call…Wisconsin is moving in the wrong direction. Our energy companies are doubling down on burning dangerous fossil fuels to meet soaring AI data center demand, adding to the hazardous air pollution we breathe and damaging our climate. Wisconsinites are paying the price.”

Chandler said that Wisconsin needs to rapidly employ several policies including:

• Rapidly shutting down Wisconsin’s remaining coal power plants
• Ending investments in fossil fuel-burning infrastructure, such as new methane gas plants and oil pipelines
• Dramatically increasing funding for programs to help Wisconsinites save energy and money
• Investing in public transit and electric vehicle charging infrastructure
• Supporting large-scale wind and solar development
• Removing barriers to rooftop and community solar
• Cultivating  farming practices that truly store carbon in the soil and restore soil health

“These ideas are not new; in fact, many other states are already taking action,” said Chandler. “For example, Wisconsin is last in the Midwest when it comes to wind energy production, far behind our neighbors…We’ve got to realize that Wisconsin is not an island. No community is safe from the impacts of climate change. The question is, what are we — and our state leaders — doing to help?”

It’s a question young people, especially those who have grown up in an era of climate emergency, ask their elders with increasing audacity. Last year, a group of young Wisconsinites attempted to take the government to court, asking the state to eliminate laws that worsen the climate crisis and accusing those in power of robbing them of their right to a safe and stable future due to policies which contribute to climate change. In April, a Dane County judge dismissed the case, saying that although she was sympathetic to the children, that what they demanded was a political question beyond judicial review. 

“Needless to say, we strongly disagree,” said Shaeffer. Midwest Environmental Advocates, which represented the children in the court action. “These kids deserve more than sympathy. They deserve to have their day in court.” 

The children involved in the case had suffered the effects of wildfire smoke exposure in recent years, Shaeffer said in an emailed statement to the Wisconsin Examiner. One 18-year-old girl named Madeline has asthma, and must stay indoors and avoid  the smoke to avoid flare-ups,  preventing her from biking, hiking or running outdoors. Another 16-year-old named Indy must stay indoors for weeks on end due to his asthma. Caroline, a 9-year-old girl, said she feels “trapped” when heat and smoke prevent her from playing outside. Those kinds of experiences were also shared by 18-year-old Lucy, who quit the cross-country ski team because practices were cancelled due to a lack of snow in the winter and smoke in the summer. 16-year-old Ted must do farm chores when smoke is heavy in the air. And 12-year-old Elia suffers migraines which are worsened by the heat and smoke. 

President Donald Trump has repeatedly called climate change a hoax and a scam. Under both his administrations, climate policies ground to a halt as fossil fuel companies were given carte blanche to “drill baby drill,” as Trump is fond of saying.

“These are the real, lived experiences of Wisconsin young people whose health and wellbeing are being harmed by state laws that exacerbate climate change,” said Shaeffer. “We believe the court has both the authority and the obligation to address that harm.”

Last week, for a brief, beautiful span of days, all three of our young-adult daughters were immersed in nature, reveling in the delicious freedom of summertime. One, a camp counselor, was leading a group on a two-week trek through Yellowstone National Park. She sent us photos of the mountains, campfires, sweaty, grinning campers, a herd of bison they encountered by the side of the road. The other two sisters were on a canoe trip in the Boundary Waters Canoe Area Wilderness. They paddled from lake to lake, fell asleep to the sound of loons, woke up early to plunge in the crystal clear water.

Just as all three girls were ending their trips, more than a dozen wildfires swept through the Superior National Forest, prompting the Forest Service to close all entry points to the Boundary Waters. Some visitors were stranded. Eight Forest Service rangers paddled in to rescue people throughout the 150-mile stretch of wilderness on the U.S.-Canadian border. Our daughter who led the trip to Yellowstone returned to her base camp in Grand Marais, Minnesota, to learn that further trips have been canceled. A group of campers who were stuck in the Boundary Waters had to be rescued by helicopter. The smoke was chokingly thick. “It feels like the apocalypse,” she texted.

In Madison we woke up Thursday morning to the stinging haze of wildfire smoke blanketing the city, drifting down on us from the same forest fires.

The abrupt end of summer’s idyll is a heartache, not just for the immediate shock, but for what it means — a world on fire, a feeling of dread of the losses to come. There is no escape from the rapidly accelerating disasters caused by climate change. All of us are touched by it in our interconnected world. Yet somehow, we can’t get our act together to respond. As a country, we seem determined to kid ourselves about what we are seeing with our own eyes. Wisconsin U.S. Rep. Tom Tiffany, the Republican candidate for governor, has called warnings about extreme weather triggered by climate change “doomsaying, sky-is-falling rhetoric.”

Last summer, Tiffany and fellow Wisconsin Republican U.S. Rep. Glenn Grothman, along with three of their Republican colleagues from Minnesota wrote a letter to the Canadian embassy to complain that wildfire smoke was ruining summer across the Midwest.

“In our neck of the woods, summer months are the best time of the year to spend time outdoors recreating, enjoying time with family, and creating new memories, but this wildfire smoke makes it difficult to do all those things,” Tiffany and his colleagues wrote, demanding to know what the Canadians planned to do about it. Tens of thousands of Canadians were being displaced by raging fires at the time. “With all the technology that we have at our disposal, both in preventing and fighting wildfires, this worrisome trend can be reversed if proper action is taken,” Tiffany and his colleagues wrote.

Wildfires are getting worse because of climate change. The problem is particularly acute for Canada, where the Arctic region is rapidly warming and hotter, drier summers are turning forest land into a tinderbox, where a stray lightning strike can start a conflagration. The same thing is happening in the Superior National Forest this summer, where the fires are caused by lightning and the hot, dry conditions that are not letting up.

Instead of working to mitigate the threat, the Trump administration has dismantled the arm of the U.S. Environmental Protection Agency that researches wildfires and other climate-related threats, as well as the Forest Service’s firefighting teams. In 2025, the Forest Service lost nearly 6,000 employees. Trump’s fiscal year 2027 budget aims to cut the Forest Service budget by 75%. 

Tiffany’s scolding letter to Canada aside, the policies he has supported under Trump have directly increased fire hazards. To the eight rangers now searching the Boundary Waters for people trapped by the fires, the Forest Service office in Minnesota is hoping to add back some of the staff they’ve lost to Trump’s ill-advised reorganization and cuts. 

“We are actively trying through our existing staff to reach out to former staff that have retired or moved to another position off-forest that still have firefighting skills and credentials,” Forest Service spokesperson Christine Kolinski told the Minnesota Star Tribune. 

This summer’s fires are more than just a wake-up call. They are a five-alarm emergency alert. We are losing so much so fast. We all have a stake in facing it and acting now. It does no good to pretend the disaster isn’t happening or to blame our neighbors, as if they could fix things for us by getting out their rakes. The least we can demand of our political leaders is that they stop dismantling the only tools we have to fight the incineration of our world. We owe that much to every kid who looks forward to every future summer.