Here’s how you can compare pollution from cars and wildfires

Here’s how you can compare pollution from cars and wildfires

11 March 2018

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USA – Q: With all the forest fires that have raged in the West the past few months, I’m curious: Has it ever been estimated how many cars it would take to emit the equivalent pollution of, say, the fires in California?

Daniel Stocker, of Belleville

A: After you hear these numbers, you’ll probably want Mother Nature hauled before the Environmental Protection Agency for an intense grilling.

In just one week last October, the fires in Northern California produced the same amount of pollution as all the cars in the Golden State did for an entire year, according to Sean Raffuse, an air-quality analyst at the Crocker Nuclear Laboratory at the University of California, Davis.

In a story reported by CNN, Raffuse estimated that from Oct. 8-14, the wildfires in Napa, Sonoma and Solano counties alone released more than 10,000 tons of what is called particle matter (PM) 2.5. PM is the mix of solid particles and liquid droplets found in air. PM 2.5 refers to particles with a diameter of 2.5 micrometers or smaller. To put it in perspective, they’re 30 times smaller than the width of a human hair and readily inhalable.

Raffuse said the 10,000 tons is nearly equivalent to the estimate of PM 2.5 released by all of the on-road vehicles in the state during 2014, the most recent year such data was available. In fact, the air quality in the Bay Area in mid-October was nearly as bad as Beijing — 162 PM 2.5 in China’s capital versus 158 PM 2.5 in California.

The types of pollution, of course, were very different — cars and coal in China vs. mostly trees in California — but the results are often the same.

“We found that people were more likely to be hospitalized during and shortly after exposure to wildfire smoke than during other periods,” Michelle Bell, a Yale professor of environmental health, told CNN.

Which meant that Bay Area doctors and emergency rooms likely girded themselves for a flood of new patients. On Oct. 10, the area saw its worst air pollution in history with a score of 486. That’s near the upper limit of the EPA’s Air Quality Index, which lists 301-500 as “hazardous.” (The AQI based on ground-level ozone, particles, carbon monoxide and sulfur dioxide.)

If you’ve followed the news, however, you know the California fires were not an anomaly. Back in 1997, for example, similar fires swept across Indonesia, where forests were covered with carbon-rich peat measuring up to 65 feet thick. As a result, those fires were thought to have released perhaps up to 2.5 billion tons of carbon — or 40 percent of the total world emissions at the time, according to estimates published at

Fortunately, because of the different makeup of the trees and land, North American fires do not release nearly as much carbon. In 2006, for example, roughly 100,000 wildfires destroyed about 10 million acres of forest in the United States. Using Environmental Canada estimates, these produced about 48 million tons of carbon, which is less than 1 percent of the world’s annual output.

On the other hand, the estimates don’t take into account the carbon that would later be released by the vegetation that will decay once the fires are extinguished. Nor does it reflect the amount of carbon dioxide that the forest would have absorbed from the atmosphere had it not burned.

And here’s what’s worse: While skeptics certainly will pooh-pooh the warnings, many experts say global warming is increasing the wildfire threat. According to a University of Arizona study, the wildfire season now lasts roughly 21/2 months longer than it did in the mid-1980s, primarily because of earlier snow melts in the West. Early snow melts mean that dried brush spends more time lying around, waiting for a lightning strike or a carelessly thrown cigarette butt to ignite it. In addition, a University of Kansas study predicted that carbon dioxide emissions from wildfires will double by the year 2100.

Yes, as my forestry buddy at the University of Missouri used to tell me, fires are needed to replenish the soil and clear away rot. And even if all humans would relocate to Mars tomorrow, thousands of fires still would be sparked by lighting; in fact, in 2006, natural fires were responsible for about half of those 10 million burnt acres. Even Native Americans used the power of fire in their daily lives: Before 1800, they are thought to have burned about 4.5 million acres a year to manage game, help grow edible crops and deprive enemies of cover.

But if the global warming proponents are correct, the circle may become ever more vicious. Changing climate will lead to more destructive fires, which will add to the carbon pollution while destroying the trees that would help process that carbon. This, in turn, may lead to more global warming, more fires, etc., etc., ad infinitum.

Something to think about, at the very least.
Today’s trivia

Who preceded Smokey Bear as the nation’s fire prevention mascot?

Answer to Sunday’s trivia: In 1926, Bulova is thought to have produced the first radio advertisement when countless Americans one night heard, “At the tone, it’s 8 o’clock Bulova Watch Time.” Fifteen years later, they ushered in the age of TV advertising with the first commercial ever on the boob tube. It was July 1, 1941, the first day that the Federal Communications Commission allowed advertising on TV. Just before a baseball game between the Brooklyn Dodgers and Philadelphia Phillies on WNBT in New York, viewers saw a drawing of the continental United States with a clock sporting “Bulova Watch Time” on its face. The grainy, shaky image was shown for 10 seconds as announcer Ray Forrest said, “America runs on Bulova.” The spot cost just $4, and only the few thousand people who owned a TV set back then saw it, but it started an advertising revolution. To see it, go to

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