Cigarette butts release harmful toxins even after they are extinguished, finds study
Every extinguished cigarette butt gives out up to 14% of the nicotine that a burning cigarette gives off in one day
Discarded cigarette butts are just as bad for our bodies as lit ones because they release dangerous toxins even after they are put out.
A used butt — one that is cold to the touch — can, in a single day, give off the equivalent of up to 14% of the nicotine that an actively burning cigarette emits, according to researchers from the National Institute of Standards and Technology (NIST), US.
The results provide evidence that chemicals remain long after the cigarette goes out. "The nicotine coming from a butt over seven days could be comparable to the nicotine emitted from mainstream and sidestream (second- or third hand) smoke during active smoking, "says Dustin Poppendieck from NIST's Engineering Lab.
The analysis adds: "This means if you don't empty an ashtray in your home for a week, the amount of nicotine exposure to nonsmokers could be double the current estimates."
Cigarettes emit between 40,000 to 100,000 different chemicals when they are actively smoked. However, there is not much research on what happens once the cigarette is put out.
Globally, smokers produce over five trillion cigarette butts every year. Cigarette butts are one of the most common forms of litter and are often discarded onto beaches, bus stops, roads, streets, parks, and other public places.
Over 75% of smokers have been observed to litter cigarette butts in an urban environment, including 94% of those who did not extinguish their cigarettes. Typically, a cigarette butt includes three major components, that is, ash, unburned tobacco, and the filter.
“Globally, over five trillion cigarette butts are generated every year, in which many chemicals are associated with human health risks," points out the study.
"Disposed cigarette butts in indoor and outdoor environments may prolong human exposure to chemicals produced during cigarette burning or present in cigarettes before burning. However, little attention has been paid to airborne emissions from cigarette butts,” says the study published in Indoor Air.
A leading cigarette brand consumed in the US market was chosen as the target cigarette in this study. The team focused on emissions from discarded butts, which are largely just used filters.
The researchers measured eight of the hundreds of chemicals typically emitted from 2100 cigarettes that were artificially smoked and extinguished, including four that are on the FDA list of harmful and potentially harmful constituents.
The experts looked at what are the types different conditions that a cigarette butt might be exposed to and how that might affect emissions. For example, they tried to determine if environmental differences in temperature, humidity, and saturation in water would change emission rates.
The team also measured triacetin, a plasticizer often used to make filters stiff. Filters were added to cigarettes in the 1950s. While they do collect part of what comes off a burning cigarette, filters do not fully negate the exposure from inhaling tobacco smoke.
"Filters provide a kind of handle for cigarette users who want to avoid burning their lips or fingers, wasting tobacco, or having to pull stray tobacco bits off their tongues. Triacetin can make up as much as 10% of a filter, and its low volatility means it doesn't evaporate quickly at normal temperatures, so it could be a good indicator of long-term emissions from a butt."
"Experiments in this study indicate that nicotine emission from cigarette butts may contribute substantially to aggregate nicotine exposure due to cigarette consumption,” says the team.
Cigarettes were carefully lit and "smoked" in a machine before being recorded in the lab at NIST.
The researchers built a "smoking machine" that uses robotic movements to simulate what humans do when they light up. The machine was made to move air through each cigarette in the same way, to remove some potential variables associated with the behavior of actual smokers.
Extinguished cigarettes were placed in a walk-in, stainless steel chamber to characterize airborne emissions.
The NIST measurements were performed under an inter-agency agreement with the Food and Drug Administration (FDA) as part of its analysis of the overall impact of cigarette smoking on people's lives.
The experts found the amount of chemical a person might be potentially exposed to from a cigarette butt is not insignificant — it could be quarter or 20% of the chemical a person is exposed to if someone was smoking nearby, says the study.
The analysis shows that most of the chemicals from the extinguished butts were emitted in the first 24 hours. However, five days later, nicotine and triacetin concentrations were still about 50% of the initial level. The team also found that butts emitted these chemicals at higher rates when the air temperature was higher.
According to the researchers, the findings are significant and could have important impacts when butts are disposed of indoors or in cars.
"You might think that by never smoking in your car when kids are present, you are protecting the nonsmokers or children around you. But if the ashtray in your hot car is full of butts that are emitting these chemicals, exposure is happening," says Poppendieck in the study.
Based on their findings, the team says that people can put used butts in sealable metal or glass jars with sand instead of leaving them out in the open.