The sky was a field of white when I opened my blinds in suburban Minnesota yesterday morning. Not the puffy wisps of white that dot a deep blue, but a dreary and ghastly mat of unfeeling white. Monotone.
Families across the northern United States have been seeing a similar sight this July. Hazy smoke in the mornings, unnaturally beautiful apricot sunsets. There has been something in the air. Like most of America’s problems, this one came from Canada. Something tells me that a wall won’t solve this one.
Wildfires, crossing the US-Canada border from Ontario and popping up across the northern Boundary Waters, are creating thick clouds of dense smoke. By July 16th, the fires had burned over 50,000 acres with minimal containment reported. The Minnesota State Climatology Office describes this event as the state’s worst and most intense smoke event in recorded history.
The direct cause of these Minnesota fires was dry lightning (storms with little rain) that ignited dry vegetation. A combination of hot weather, low humidity, and blowing winds has caused them to spread. Particles released by such fires are carried southward by wind currents, and local atmospheric conditions determine whether the accumulated air pollution descends to breathing level. While it would be easy to blame climate change and call it a day, the situation is more nuanced than that. In this case, climate change did indeed exacerbate the fires, but it did not cause them; hot weather and reduced precipitation dried out plants, influencing how quickly fires spread, how intensely they burned, and how long the wildfire season lasts. Global warming set a stage for wildfires, preparing for lightning to strike.
The Science of White Smog
Wildfire-smoke haze, stretched across polluted skylines, is created when light bounces off an enormous number of airborne particles. Smoke particles absorb and scatter sunlight, washing out the natural contrast of a landscape, hiding distant buildings, and giving the atmosphere a milky-white appearance. During sunset, light travels through the dense mat of air. Smoke blocks shorter wavelengths (blue/violet) while longer wavelengths (red/orange) bleed through, creating the rich, brilliant skylines seen recently across the United States. Despite being an indicator, visible colour isn’t a reliable safety measurement. Pale, clear skies may still contain unhealthy concentrations of harmful particulates.
Measuring Air Pollution
To translate this information into an easily understandable system, the Air Quality Index (AQI) converts measured air pollution into a colour-coded public health scale. Here are the categories:
- 0–50, green: good
- 51–100, yellow: moderate
- 101–150, orange: unhealthy for sensitive groups
- 151–200, red: unhealthy for everyone
- 201–300, purple: very unhealthy
- Above 300, maroon: hazardous for everyone
In this scale, ‘hazardous’ represents a public health risk such that authorities advise everyone to avoid outdoor activity. Sensitive groups like children, the elderly, and pregnant women are told to remain indoors and minimise exertion.
This week, AQI readings in Minnesota reached nearly 1000, three times above the level where the government declares a public health emergency. This level of pollution is so extreme that these toxic particles cause immediate irritation to the eyes, nose, and throat; short exposure can trigger asthma attacks, chest pain, and shortness of breath.
The U.S. EPA (Environmental Protection Agency) sets a daily ‘safe limit’ of 35 micrograms per cubic meter for particulates. This week, northern Minnesota saw hourly measurements over 1100 micrograms per cubic meter – thirty times the safe limit. This size of particulate, PM2.5, refers to microscopic airborne particles that are 2.5 microns in diameter or below – thirty times smaller than a single human hair. Particles at this size bypass the body’s natural defences, lodging themselves into the lungs and entering the bloodstream. Small particles can remain airborne for long periods of time, allowing them to travel hundreds or thousands of miles from the fire. The accumulation of these foreign particles can lead to long-term conditions like Chronic Obstructive Pulmonary Disease, increase the risk of cognitive decline through Alzheimer’s disease, harm kidney function, and result in reproductive complications. Essentially, when these particles enter your body, they stay and build up. Fifty years later, suddenly, the impact becomes clear.
Global Warming and Air Pollution
In 2022, Minnesota issued 13 air quality alerts covering 42 days. In 2023, the state jumped to 22 alerts across 52 days. A 2025 report found that unhealthy air days had risen in number over the preceding five years, with a rise in orange and red alerts issued. And of course, this week of 2026 is unprecedented in all of the state’s history.
A warming climate is making wildfires ‘bigger, hotter, and more destructive’ across Canada, with the nation ‘warming twice as fast as the global average’. Warmer atmospheres create greater evaporative demands, meaning that they are ‘thirstier’. A thirsty sky pulls moisture from soil and vegetation, drying fields rapidly between rainfall events. Warmer skies also require greater volumes of water before rainfall occurs, resulting in shifting precipitation patterns and potentially inconsistent rainfall.
While many parts of Minnesota have experienced an increase in annual precipitation, fire danger is contingent on the timing of rainfall instead of yearly totals. A hot, windy, dry spell can induce drought; alongside low humidity and high evaporation, vegetation that grew during a wet winter suddenly becomes flammable.
Across America, the number of large fires and the total wildfire area burned have roughly doubled since 1984, with fire seasons lengthening in many regions. Earlier snowmelt, hotter summers, and shifts in spring rainfall contribute to longer periods with flammable vegetation.
An attribution study from 2023 analysed extreme fire-weather conditions in eastern Canada, showing that anthropogenic warming more than doubled the likelihood of flammable conditions, making widespread burning more probable. Similarly, the Palisades Fire in January 2025 was linked to human-caused warming. A World Weather Attribution analysis estimated that such extreme fire weather had become approximately 35% more likely and about 6% more intense, lengthening the regional dry season by around 23 days.
A warming world, in places like Minnesota, is becoming a more flammable one as well.
A Dangerous and Unequal Burden
The AQI abstracts the level of danger. Numbers and coloured maps help everyday people to decide whether to send children outside or to exercise outdoors, but they may also flatten ecological crises into individual responsibilities. People are expected to check an app, buy a purifier, and invest in face masks. An AQI value doesn’t explain who created the underlying conditions, why certain levels are considered a hazard and not others, the importance of baseline health conditions, or who can afford protection while others cannot.
Air pollution events like those caused by recent wildfires further show the limits of local environmental regulation. Minnesota can reduce emissions from its own factories, vehicles, and power plants, but smoke crosses state and national boundaries. Similarly, global warming does not care where a line has been drawn on a map. When natural disasters strike, it is the collective efforts of people worldwide that have the potential to lessen their severity. When we fail to act, the damage does not stay neatly contained somewhere else. It travels.
As with most cases of environmental injustice, a socio-economic divide determines who feels the greatest impacts of the ongoing air pollution. Those with the financial means to purchase air conditioning rather than opening windows, those with the luxury to work from home or to not perform manual outdoor labour, and those with sealed homes can mitigate the impacts of air pollution.
While wildfire smoke may initially display similar exposures to all populations, blanketing affluent and disadvantaged communities simultaneously, differences in chronic exposure and vulnerability shape impacts on marginalised populations. An AQI will tell you the relative air quality in a city, but individual dosage levels are dependent upon vocation, access to filtration, and housing. Low-income households are more likely to live in older, poorly-sealed housing, increasing their daily exposure. Furthermore, marginalised populations often enter a wildfire event with higher rates of preexisting conditions like asthma, cardiovascular disease, and diabetes, which all increase their vulnerability to the hazard. Chronic industrial pollution, inadequate access to healthcare, occupational hazards, stress, and substandard housing all contribute to one’s vulnerability to wildfire smoke inhalation. Moreover, rural areas in the U.S. suffer from insufficiencies in monitoring data, causing disparities in information access. Longer episodes, higher peaks, and sustained pollution may be lost to state averages due to how sparse regulatory monitors are outside the city.
Indigenous American Tribal Nations like the Ojibwe were especially affected during this wildfire as federal reservations were geographically nearby. Northern fires threatened lands, culturally significant species, and access to forests and water that cannot be described in property-loss figures alone. Traditionally, Ojibwe fire management (Ishkode) relied upon deliberate, controlled fires to clear underbrush, return nutrients to the soil, and preserve ecological balances. These low-intensity fires both helped grow crops like sweetgrass and blueberries and prevented the buildup of fuel for destructive wildfires. Over the past century, government restrictions, land dispossession, and fire-suppression policies disrupted many of these practices, allowing denser vegetation and combustible material to accumulate in some landscapes.
The disproportionate effects of wildfire smoke on Tribal communities reflect more than the geographic proximity to the hazard. When Indigenous communities lose the authority to manage their own lands and environmental authority is rooted purely in colonial land-management policies, they face heightened health risks from wildfire smoke.
In a rapidly warming world, where extreme weather events are becoming more intense and more frequent, America’s approach to natural disasters will fall upon difficult questions: which groups are worth spending money on? At what point does a crisis become significant enough to issue a warning? Which, if any, lives are worth more than others?
The white sky conceals the differential burden that each person faces. Smoke crosses borders, but protection is divided by income, occupation, housing, age, and health.
A Warning for a Heating Future
Governments often wait until environmental crises have already arrived, instead of preventing them in the first place. This should worry everyone, even if the smoke is yet to arrive on your doorstep. Global warming is creating a world where air pollution is becoming more common, more intense, and harder to avoid. The devastating headlines we see as rare emergencies are becoming routine events. As the atmosphere swelters, forests burn, fire seasons lengthen, and smoke spreads, the privilege of clean air will come at a cost. And it will be a privilege concentrated in the hands of those with the means to afford it.
It is easy to envision a terrifying reality where air quality descends from a public commodity into a private product, something purchased in little cans, something reserved for the highest bidder. Ten years ago, in 2016, residents in polluted Chinese cities like Beijing and Shanghai were buying 20-ounce bottles of countryside British air. Fresh air was sold at a premium £80 ($115) per bottle. While this company (Aethaer) shifted away from this product, the bottled air showed how desperation for clean air draws exorbitant prices. Even plans for relying upon bottled air or fancy filtration devices are ignoring the root of the problem. Rather than cleaning up our polluted air, we should be preventing its pollution from the start.
While we continue to treat climate change as a distant, faraway future, the impacts are felt through the irritation in our lungs and the particles swimming in our blood. Massive wildfires like those ongoing in North America showcase the ubiquity of air pollution while forcing families to temporarily face difficult tradeoffs between harmful exposure, the ability to stay cool and safe, or survival itself. In a future where clean air fails to remain an inherent natural right and becomes a market product, such tradeoffs between health and freedom will define each aspect of our lives.
This does not mean that people are powerless. We can push for stronger clean-air standards, advocate for policies that target prevention instead of only response, and invest in public transportation, renewable energy, and community fire preparedness. Anyone can support groups like the Clean Air Fund, check on vulnerable neighbours during smoke events, and blatantly refuse to treat gritty, polluted air as normal. Rather than becoming desensitised to the environmental crises happening far away, it is critical to recognise that we all share the same air. If we continue sitting idly by waiting for the next wave of smoke to arrive, it is only a matter of time before clean air becomes a luxury available to a select few.
The smoke I see out the window, murky and devoid of colour, is not just above me. It is entering homes, schools, worksites, forests, and bodies.
It is a warning for the future and not an exception. Our warming planet is creating conditions where wildfires and particulate smog are becoming more common and severe. The air is poison. The question that remains is who has the privilege of not having to breathe it.
_
Joey Wu is a Master’s student at Christ Church, Oxford reading Water Science, Policy, and Management, and a University of Pennsylvania alumnus in Bioengineering and Environmental Science. Joey brings a global perspective, drawing on his work founding Waterroots and engaging with institutions from the UN to the World Bank to amplify grassroots stories often left out of mainstream narratives. Read more of his work here.
Leave a comment