Sign In or Create an Account.

By continuing, you agree to the Terms of Service and acknowledge our Privacy Policy

Climate

The 5 Big Questions About the 2023 Wildfire Smoke Crisis

We have answers.

A question mark amid a wildfire.
Heatmap Illustration/Getty Images

The eastern and northern United States are suffering under a hazy, poisonous cloud of wildfire smoke, produced by out-of-control forest fires in Quebec and Nova Scotia. The most toxic soot and ash are sitting virtually on top of North America’s most densely populated corridor, clouding the air in New York City; Toronto; Ottawa; Philadelphia, Washington, D.C.; and Norfolk, Virginia.

Air pollution alerts are in effect across the United States and Canada, affecting roughly 150 million people.

This is Heatmap’s set of commonly asked questions about the crisis. We’ll keep it updated throughout the event.

Why is it so smoky now?

Hundreds of wildfires have raged across northern Quebec for the past few weeks, driven by unusually warm and dry conditions.

Then on Monday, a low-pressure system surrounded by counterclockwise winds moved just off New England’s coast. Its strong, dry gusts fanned the flames in Canada, then pushed the resulting smoke and ash into the eastern United States.

Intense Canadian fires are unusual this early in the season, but the fires this year were fed by a warm spring and drought-like condition, Kent Moore, an atmospheric-physics professor at the University of Toronto, told me. Because the fires took hold before the vegetation could “green up” for the spring, the conflagrations grew more rapidly than they normally would, he said.

The dry conditions also helped the fires ignite the soil itself. “Because the soil was so dry — because of the dry winter and the dry spring — the fire got into the ground,” he said. “The vegetation below ground started to burn, and those are much harder to put out.”

How does the current crisis compare to previous events?

This is likely one of America’s worst days for air pollution in several decades, in terms of the number of people affected and the severity of the exposure, Marshall Burke, an economist and sustainability professor at Stanford, told me.

“It’s pretty off the chart,” Burke said. Wildfire smoke is affecting New York City much more acutely — and much earlier in the year — than it has at any time since 2006, when contemporary air-pollution data began to be kept.

What’s the connection between the 2023 Canadian wildfires and climate change?

It is difficult to attribute a single unprecedented event to climate change, and the climatology of wildfires in eastern North America is particularly challenging. (Climate change has more clearly worsened wildfires out West.) “This is probably an unlucky year for Canada, as far as wildfires go,” Moore, the atmospheric physicist, said.

But wildfires will become more likely across Canada as the climate changes, he said. And while climate change should broadly increase rainfall across Canada, it will also increase the likelihood of heat waves and more extreme spring and summer temperatures, which can make wildfires more likely.

“Nova Scotia has always had wildfires. It’s just they’ve had more wildfires this year than they have on average for the whole year,” he said. “There’s always going to be wildfires, but there’s going to be more of them.” As Canadian cities sprawl into previously uninhabited woodland areas, he added, the human impacts of wildfires will increase — even if the number and intensity of wildfires does not.

What should I do about the air pollution?

First, consult the air quality index at AirNow.gov. The AQI is a unit-less index of air quality running from zero to 500; any reading above 100 would rank as unusually polluted in the United States. On Wednesday afternoon, some air sensors in New York and New Jersey indicated that the AQI exceeded 400.

If it’s higher than 100, then the most vulnerable groups of people — including children, the elderly, anyone with a cardiopulmonary condition, and pregnant women — should limit strenuous activity outdoors. If higher than 150, then people should generally try to limit their outdoor activity; at levels above 200, the air is considered unhealthy and everyone should try to go outside as little as possible.

If you think you might be especially vulnerable, err on the side of caution. Recently, a body of new and large-scale studies have shown that air pollution is generally worse for the body and brain than previously thought.

Then, if you’re in an area with hazardous air pollution, consider how to limit your exposure to the air as much as possible. Keep your doors and windows closed. An air filter outfitted with a HEPA filter can improve the air in a home or apartment. It should generally be closer to the most sensitive people.

“Any pregnant moms — if my wife or anyone I knew was pregnant right now — I would be texting them to stay inside and sit by an air filter,” Burke told me. Exposure to severe air pollution during pregnancy has been shown to increase the risk of preterm birth, and it can reduce a child’s lifelong earnings, cognitive performance, and other indicators, he said.

A KN95 or N95 mask — the type of high-filtration mask used to prevent COVID infection — can also significantly limit your exposure to soot and ash. If you are in a sensitive group or are worried about air pollution’s health effects, you could consider wearing a mask inside if you have no other way to filter the air.

Get the best of Heatmap directly in your inbox:

* indicates required
  • Green

    You’re out of free articles.

    Subscribe today to experience Heatmap’s expert analysis 
of climate change, clean energy, and sustainability.
    To continue reading
    Create a free account or sign in to unlock more free articles.
    or
    Please enter an email address
    By continuing, you agree to the Terms of Service and acknowledge our Privacy Policy
    Politics

    Trump Promised Deregulation. His New Law Would Regulate Energy to Death.

    The foreign entities of concern rules in the One Big Beautiful Bill would place gigantic new burdens on developers.

    Power lines and Trump's tie.
    Heatmap Illustration/Getty Images

    Trump campaigned on cutting red tape for energy development. At the start of his second term, he signed an executive order titled, “Unleashing Prosperity Through Deregulation,” promising to kill 10 regulations for each new one he enacted.

    The order deems federal regulations an “ever-expanding morass” that “imposes massive costs on the lives of millions of Americans, creates a substantial restraint on our economic growth and ability to build and innovate, and hampers our global competitiveness.” It goes on to say that these regulations “are often difficult for the average person or business to understand,” that they are so complicated that they ultimately increase the cost of compliance, as well as the risks of non-compliance.

    Keep reading...Show less
    Blue
    Politics

    AM Briefing: The Megabill Goes to the House

    On the budget debate, MethaneSAT’s untimely demise, and Nvidia

    House Republicans Are Already Divided on the Megabill
    Heatmap Illustration/Getty Images

    Current conditions: The northwestern U.S. faces “above average significant wildfire potential” for July • A month’s worth of rain fell over just 12 hours in China’s Hubei province, forcing evacuations • The top floor of the Eiffel Tower is closed today due to extreme heat.

    THE TOP FIVE

    1. House takes up GOP’s megabill

    The Senate finally passed its version of Trump’s One Big Beautiful Bill Act Tuesday morning, sending the tax package back to the House in hopes of delivering it to Trump by the July 4 holiday. The excise tax on renewables that had been stuffed into the bill over the weekend was removed after Senator Lisa Murkowski of Alaska struck a deal with the Senate leadership designed to secure her vote. In her piece examining exactly what’s in the bill, Heatmap’s Emily Pontecorvo explains that even without the excise tax, the bill would “gum up the works for clean energy projects across the spectrum due to new phase-out schedules for tax credits and fast-approaching deadlines to meet complex foreign sourcing rules.” Debate on the legislation begins on the House floor today. House Speaker Mike Johnson has said he doesn’t like the legislation, and a handful of other Republicans have already signaled they won’t vote for it.

    Keep reading...Show less
    Yellow
    Podcast

    Shift Key Summer School: What Is a Watt?

    Jesse teaches Rob the basics of energy, power, and what it all has to do with the grid.

    Power lines.
    Heatmap Illustration/Getty Images

    What is the difference between energy and power? How does the power grid work? And what’s the difference between a megawatt and a megawatt-hour?

    On this week’s episode, we answer those questions and many, many more. This is the start of a new series: Shift Key Summer School. It’s a series of introductory “lecture conversations” meant to cover the basics of energy and the power grid for listeners of every experience level and background. In less than an hour, we try to get you up to speed on how to think about energy, power, horsepower, volts, amps, and what uses (approximately) 1 watt-hour, 1 kilowatt-hour, 1 megawatt-hour, and 1 gigawatt-hour.

    Keep reading...Show less
    Green