Sign In or Create an Account.

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

Climate

Wednesday Was the Worst Day for Wildfire Pollution in U.S. History

The finding by Stanford researchers confirms the danger — and lack of precedent — for the East Coast’s ongoing wildfire smoke crisis.

The Chrysler Building.
Heatmap Illustration/Getty Images

Wednesday, June 7, was by far the worst day for wildfire smoke exposure in American history, subjecting more people to greater amounts of soot and ash than any previous day on record, according to a new and rapid analysis conducted by Stanford researchers.

The finding confirms the danger — and lack of precedent — for the ongoing wildfire smoke crisis, which has smothered the northern and eastern United States in an acrid haze. Since Monday, a strong low-pressure system has fanned dozens of wildfires in northern Quebec, then blown the resulting smoke into North America’s most densely populated corridor, covering New York City, Philadelphia, Washington, D.C., and Toronto.

Even as the smoke moved in, it made history. Tuesday became the country’s third-worst day for wildfire smoke on record, according to research from the same Stanford team. Only two days in September 2020 — when vast wildfires sheathed California, Idaho, and the Pacific Northwest in smoke — had exposed more Americans to higher intensities of toxic particulate matter.

Wednesday smashed those records. By the late afternoon, New York and New Jersey’s sky had turned a pungent orange, and their air quality fell to “very unhealthy” or even “hazardous” levels for all groups, the worst category. The rest of the Northeast and Mid-Atlantic faced similar or only slightly better conditions, and wildfire smoke at least somewhat afflicted virtually everywhere between Minneapolis, Atlanta, and Boston.

Stanford chart.Stanford.

The vast geographic sweep of the smoke — and the fact that it was so intense in the country’s biggest city — obliterated the old record. The country’s previous worst day for smoke exposure was September 13, 2020, when nearly 35 million Americans were exposed to more than 50 micrograms per cubic meter of microscopic soot and ash. That is five times worse than what the World Health Organization considers safe.

But on Wednesday, roughly 62 million Americans — nearly one in five — were exposed to such high levels of particulate matter.

Get one great climate story directly in your inbox every day:

* indicates required
  • It was “just a massive, awful event, with highly populated areas getting hit with unprecedented levels of pollution,” Marshall Burke, an economist and professor at the Stanford Doerr School of Sustainability, said on Twitter. He leads the school’s Environmental Change and Human Outcomes Lab, which conducted the research.

    The study encompassed data from 2006 to 2023. The researchers studied which days were worst on a population- and exposure-adjusted basis. In other words, on which days in history were the most Americans subjected to the most intense amounts of wildfire smoke?

    Because the U.S. population has grown over time, and because wildfires have enlarged over the past few decades, it is unlikely that any days prior to 2006 saw so many Americans exposed to so much smoke. Most of the record days in the data set have happened since 2018.

    With the new record in place, Tuesday falls to the fourth-worst day for wildfire smoke on record.

    Speaking earlier this week, Burke said that what made this event so distinct from previous ones is that the wildfire smoke hit the country’s largest and most populated cities. “It’s mainly due to the East Coast having so many people. It’s New York, Boston, D.C., Detroit. Out West, our cities are just smaller,” he told me.

    Read more about the wildfire smoke engulfing the East Coast:

    Wednesday Was the Worst Day for Wildfire Pollution in U.S. History

    The 5 Big Questions About the 2023 Wildfire Smoke Crisis

    Nowhere Is ‘Climate Proof’

    When There’s Smoke, Getting Indoors Isn’t Enough

    How Many People Will This Smoke Kill?

    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
    Carbon Removal

    Carbon Removal After Microsoft

    Though the tech giant did not say its purchasing pause is permanent, the change will have lasting ripple effects.

    Carbon removal.
    Heatmap Illustration/Getty Images, Climeworks, Heirloom Carbon

    What does an industry do when it’s lost 80% of its annual demand?

    The carbon removal business is trying to figure that out.

    Keep reading...Show less
    Yellow
    Spotlight

    The Data Center Transmission Brawls Are Just Getting Started

    What happens when one of energy’s oldest bottlenecks meets its newest demand driver?

    Power line construction.
    Heatmap Illustration/Getty Images

    Often the biggest impediment to building renewable energy projects or data center infrastructure isn’t getting government approvals, it’s overcoming local opposition. When it comes to the transmission that connects energy to the grid, however, companies and politicians of all stripes are used to being most concerned about those at the top – the politicians and regulators at every level who can’t seem to get their acts together.

    What will happen when the fiery fights on each end of the wire meet the broken, unplanned spaghetti monster of grid development our country struggles with today? Nothing great.

    Keep reading...Show less
    Yellow
    Hotspots

    Will Maine Veto the First State-Wide Data Center Ban?

    Plus more of the week’s biggest development fights.

    The United States.
    Heatmap Illustration/Getty Images

    1. Franklin County, Maine – The fate of the first statewide data center ban hinges on whether a governor running for a Democratic Senate nomination is willing to veto over a single town’s project.

    • On Wednesday, the Maine legislature passed a total ban on new data center projects through the end of 2027, making it the first legislative body to send such a bill to a governor’s desk. Governor Janet Mills, who is running for Democrats’ nomination to the Senate, opposed the bill prior to the vote on the grounds that it would halt a single data center project in a small town. Between $10 million and $12 million has already been sunk into renovating the site of a former paper mill in Jay, population 4,600, into a future data center. Mills implored lawmakers to put an exemption into the bill for that site specifically, stating it would otherwise cost too many jobs.
    • It’s unclear whether Mills will sign or veto the bill. Her office has not said whether she would sign the bill without the Jay exemption and did not reply to a request for comment. Neither did the campaign for Graham Platner, an Iraq War veteran and political novice running competitively against Mills for the Senate nomination. Platner has said little about data centers so far on the campaign trail.
    • It’s safe to say that the course of Democratic policy may shift if Mills – seen as the more moderate candidate of the two running for this nomination – signs the first state-wide data center ban. Should she do so and embrace that tack, it will send a signal to other Democratic politicians and likely accelerate a further shift into supporting wide-scale moratoria.

    2. Jerome County, Idaho – The county home to the now-defunct Lava Ridge wind farm just restricted solar energy, too.

    Keep reading...Show less
    Yellow