Canadian Wildfires Choke U.S. Air

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Wildfires are tearing through Canada, as of June 5, 2025, there are approximately 203 active wildfires burning across Canada, with 102 classified as "out of control," according to the Canadian Interagency Forest Fire Centre. From British Columbia to Manitoba, these fires have forced 25,000 residents to evacuate and are now impacting air quality across the United States. Smoke has drifted into northern Minnesota, Wisconsin, the Upper Peninsula of Michigan, and parts of the Northeast and Southeast, triggering air quality alerts in multiple states.

“The smoke is not containable. It goes where it goes,” says Susan Anenberg, chair of environmental and occupational health at George Washington University, highlighting its far-reaching impact.

The Air Quality Index (AQI) in affected areas has spiked, with readings in places like New York City hitting "unhealthy" levels (AQI 169) in past events. This poor air quality stems from fine particulate matter (PM2.5), tiny particles less than 2.5 micrometers wide — about one-seventieth the width of a human hair. These particles, along with toxic chemicals like benzene, formaldehyde, and polycyclic aromatic hydrocarbons (PAHs), make wildfire smoke particularly dangerous.

CBS Canadian Wildfire 2025 air quality may June 4

“Wildfire smoke is quite a complex mixture,” explains Dr. Vijay Limaye, a climate and health scientist at the National Resources Defense Council. “It’s made up of fine particles and gases that can penetrate deeply and wreak havoc on the body.” Unlike typical air pollution, wildfire smoke can be up to 10 times more harmful due to its unique chemical makeup, including metals and synthetic compounds from burned structures.

Read until the end for a list of health conditions made worse by wildfire.

Wildfire health risks spike inflammation

The health risks are severe. Short-term exposure can cause coughing, wheezing, and eye irritation, while prolonged exposure is linked to heart attacks, strokes, and lung cancer.

A 2021 California study found wildfire PM2.5 caused more inflammation than other pollution sources. “We breathe in smoke, and it gets into our bloodstream,” says Dr. Neha Solanki, a pulmonologist at Cleveland Clinic. “The particles stick, and the immune system activates, creating inflammation.” Vulnerable groups — children, older adults, pregnant women, and those with asthma or heart conditions, face heightened risks.

For example, Chicago resident Maria Gonzalez shared, “Last summer, the smoke made my asthma so bad I couldn’t leave the house for days. It was like breathing through a straw.”

How to protect yourself from wildfire smoke

To protect yourself, experts recommend staying indoors with windows closed, using air conditioning, and employing portable air purifiers with HEPA filters, which can reduce indoor particle levels by up to 85%, per the EPA.

“You want the biggest purifier you can afford,” advises Dr. Barbara Mann, a pulmonologist at Mount Sinai. N95 respirators, when worn correctly, offer significant protection outdoors, unlike cloth or surgical masks, which fail to filter fine particles. The CDC cautions that N95s may not fit children and can be challenging for those with certain lung conditions.

For those exposed, natural remedies may help detoxify the body. Dr. Lisa Nagy, an environmental medicine specialist, suggests, “Hydration is key — drink plenty of water to flush toxins.” Antioxidant-rich foods like berries, leafy greens, and turmeric can combat inflammation. Herbal teas, such as nettle or dandelion, may support liver function, aiding detoxification.

“I started drinking green tea and eating more kale after the smoke hit,” says Minneapolis resident James Carter. “It helped me feel less sluggish.” While these remedies lack extensive research for wildfire smoke specifically, they align with general detoxification principles.

As a mass of unexplained fiercer wildfires occurs throughout the U.S. and Canada in recent years due to forestry mismanagement, the threat to air quality and public health grows. With no end in sight for Canada’s wildfire season, proactive measures are essential to protect your health from this invisible threat.

White boy with asthma using an oxygen mask

Health conditions made worse by wildfire smoke

Exposure to wildfire smoke can make a range of health conditions worse due to its toxic components, particularly fine particulate matter (PM2.5), carbon monoxide, benzene, formaldehyde, and other volatile organic compounds. Below is a detailed list of health conditions worsened by wildfire smoke exposure, supported by expert insights and studies listed in the citations list below:

Respiratory Conditions:

Asthma: Wildfire smoke, especially PM2.5, triggers asthma attacks by irritating airways, leading to wheezing, coughing, and shortness of breath. Studies show increased emergency department visits for asthma during wildfire events. For example, a California study found a 18 – 22% spike in respiratory issues during large wildfires.

Chronic Obstructive Pulmonary Disease (COPD): Smoke makes COPD symptoms worse, causing flare-ups that increase hospitalizations. The EPA notes that fine particles can worsen breathing difficulties in COPD patients.

Bronchitis and Respiratory Infections: Smoke exposure increases the risk of bronchitis and pneumonia by suppressing lung macrophage function, making individuals more susceptible to infections. A study linked wildfire smoke to higher influenza cases post-exposure.

Lung Function Decline: Even healthy individuals may experience temporary reductions in lung function and pulmonary inflammation from PM2.5, with prolonged exposure potentially causing chronic issues in vulnerable groups.

Cardiovascular Conditions:

Heart Disease: PM2.5 and carbon monoxide reduce oxygen delivery, aggravating conditions like angina and increasing the risk of heart attacks or arrhythmias. Australian studies reported higher out-of-hospital cardiac arrests during wildfire events.

Heart Failure: The EPA highlights that wildfire smoke can exacerbate heart failure, particularly in older adults, due to systemic inflammation caused by particles entering the bloodstream.

Hypertension: The stress of smoke exposure can elevate blood pressure, worsening cardiovascular outcomes in those with pre-existing hypertension.

A black boy with asthma using an oxygen mask

Mental Health Conditions:

Depression, Anxiety, and Mood Disorders: A 2025 Harvard study found that a 10 μg/m³ increase in wildfire-specific PM2.5 was linked to more emergency department visits for mental health issues, including depression and anxiety, especially among women, children, and Black and Hispanic individuals. The smoke’s physiological stress and inflammatory effects may directly worsen these conditions.

Neurological Disorders: Emerging evidence suggests wildfire smoke may increase the risk of dementia and other neurological conditions. A 2024 study reported a 21% higher odds of dementia diagnosis per 1 μg/m³ increase in wildfire PM2.5 concentration.

Other Conditions:

Diabetes: Smoke exposure can worsen glycemic control in diabetic individuals, increasing cardiovascular risks. The American Lung Association notes diabetes as a condition aggravated by wildfire smoke.

Cancer: Long-term exposure to PM2.5 and chemicals like benzene in wildfire smoke is correlated with an increased risk of lung cancer and other cancers, though evidence is mixed.

Valley Fever (Coccidioidomycosis): In California, large wildfires were linked to an 18 – 22% spike in invasive fungal infections like Valley Fever, which causes fatigue and lung damage. Valley fever is sometimes misdiagnosed as cancer on a CAT scan. This happened to the late actress, Suzanne Somers whose valley fever fungal infection was misdiagnosed as cancer.

Prenatal and Pediatric Health: Pregnant women exposed to smoke face risks of reduced birth weight and preterm birth due to altered immune responses. Children may develop new allergies or chronic asthma from repeated exposure.

Vulnerable Populations:

Children: Higher respiratory rates and developing lungs make children more susceptible to asthma, bronchitis, and emotional distress from smoke exposure.

Older Adults: Increased prevalence of heart and lung diseases in those over 65 heightens risks of severe outcomes, including mortality.

Low-income households: Limited access to air conditioning, poor nutrition, or limited access to healthcare makes health impacts worse in low-income households, particularly for respiratory and mental health conditions.

Canada’s wildfire affected areas

As of June 4, 2025, the exact number of people forced to evacuate due to wildfires in Canada varies slightly across sources but is consistently reported to be over 25,000 across three provinces: Manitoba, Saskatchewan, and Alberta.

Manitoba: Approximately 17,000 people have been evacuated, including 5,000 from Flin Flon, 600 from Cranberry Portage, 1,000 from Lynn Lake, and others from communities like Pimicikamak Cree Nation, Mathias Colomb First Nation, and Marcel Colomb First Nation.

Saskatchewan: Around 9,000 people have been evacuated, with estimates suggesting this could rise to 15,000 in the coming days. This includes 4,000 from Pelican Narrows and other northern communities.

Alberta: Approximately 1,300 people have been evacuated, notably from Swan Hills and other areas like Chipewyan Lake. Total estimates range from 25,000 to 27,000 evacuees, with Manitoba accounting for the majority. Precise numbers are challenging due to ongoing evacuations and fluctuating reports, but the figure of 25,000 is widely cited as of June 3, with slight increases noted by June 4.

Conclusion

With no end to the toxic smoke from Canada across the U.S., everyone should pay close attention to the amount of damaging smoke in their area and take measures to protect their health.

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