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Extinguished cigarette butts continue to emit chemicals hours, even days later: study

Last Updated Feb 24, 2020 at 3:57 pm EST

FILE - This March 28, 2019, file photo shows cigarette butts. (AP Photo/Jenny Kane, File)

Cigarette butts continue to emit toxins days after they've been extinguished

Cigarette butts should be kept sealed in a container like a mason jar with sand

52 million cigarettes are tossed onto Canadian streets each year

Extinguished cigarettes continue to emit chemicals hours, even days after they’ve been put-out, possibly exposing people to what some scientists are calling “after smoke” says a new U.S. study.

Cigarette butts can be found everywhere in the urban environment — on sidewalks, in parks, and gutters. The butts are the bane of city anti-littering campaigns, hated by environmentalists and derided by anti-tobacco groups.

An estimated 52 million cigarettes are tossed onto Canadian streets each year. In global terms, National Geographic Magazine reports they’re the world’s most littered item, taking a single butt an average of 25 years to break down.

While there have been lots of studies about what happens with this type of litter once it hits the ground — the effect of plastic filters, for example — very little work has been done on what some scientists call “after smoke.”

Measuring emissions in “cold butts”

To answer this question the U.S. Food and Drug Administration (FDA) asked Dustin Poppendieck and his colleagues at the National Institute of Standards and Technology in Gaithersburg, Maryland, to put together a research study.

Poppendieck said the first challenge was to figure out how to properly measure the emissions from the “cold butts.” The answer was to build a “smoking machine” that would “smoke” about 2,100 cigarettes while keeping the technicians safe from the emissions.

The “smoking machine” the scientists built to study cigarette butt emissions. (H-o/Credit: N. Hanacek/NIST)

The team then took the cigarette butts and placed them in a sealed room. Measuring equipment was used to take samples of the air.

Poppendieck said the results were quite surprising.

The group’s results showed that most of the butts continued to emit nicotine and triacetin, a plasticizer used in cigarette filters, 24 hours after they had cooled. Poppendieck said they were also surprised to see that the chemical concentrations were still at about 50 per cent of the initial level five days later.

“It was pretty eye-opening,” he said. “We’ve long known cigarette butts are an issue…but now we’ve been able to quantify the amount of nicotine they emit.”

Temperature also plays a role, he said. Warm environments (defined as being warmer than 25 C in this study) allowed the cold butts to emit the chemicals at higher rates. Cold conditions slowed the emission levels.

“In the winter you’ll see it slow down, in the summer it’ll come off really quick,” he said.

The purpose of the study was study if chemicals were still being emitted from cooled cigarette butts. (H-O/Credit: N. Hanacek/NIST)

A new avenue of exposure — “after smoke”

The traditional routes of exposure like “first hand” smoking (the actual act of smoking a cigarette) and second-hand smoke, (being exposed to the smoke produced by the cigarette) have been the subject of scientific study for years. More recently, scientists have been looking at what Poppendieck calls “third-hand” smoke — the chemicals a person might be exposed to in a smoker’s home for example. These chemicals are often found on the walls, floors, dust, and furniture of smokers’ homes. He also says this is what you might smell when a smoker gets on an elevator with you.

Where this study’s results fit into these levels of exposure is somewhere in between first and second-hand smoke, showing there’s a whole new avenue of exposure, Poppendieck said.

“This is kind of in-between first and second…not the traditional smoke that’s going into the smoker’s lungs,” he said. “It’s something else.”

Poppendieck said they are calling this exposure level  “after smoke.”

Poppendieck said he couldn’t comment as to whether this level of exposure is hazardous — more studies need to be done he says — but the results show that this “after smoke” is the equivalent of a week’s worth of exposure to smoking.

“Nicotine is addictive and you’re putting it into the environment,” he said. “After a week’s timeframe, you get as much as you would smoking.”

One example of “after smoke” exposure might be an ashtray in a car, Poppendieck said. After about a week, the emissions from those butts will permeate the vehicle and the materials of the car, exposing non-smokers to the chemicals.

Poppendieck said the key is reducing, or even eliminating exposure to after-smoke is simply disposing of the butts in a responsible way. This means emptying ashtrays and other containers right away.

One way to do this is to use a sealable container like a mason jar with some sand. There are also vacuum-sealed ashtrays available on the market, he said.

Poppendieck admits after this study he’ll never look at cigarette butts the same way again but says these butts should be treated as a toxic item that should be disposed of properly.

“The bottom line is that smokers should seal their cigarette butts,” he adds. “Be a responsible smoker, and seal them.”