Third-hand smoke

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Third-hand smoke is contamination by

Humans can be exposed to THS through inhalation, skin contact, or ingestion. Many common surfaces can accumulate THS compounds, including furnishings, walls and flooring, and clothes. THS is thought to potentially cause the greatest harm to infants and young children because younger children are more likely to put their hands in their mouths or be cuddled up to a smoker with toxins on their skin and clothes.[2] Infants also crawl on the floor and eat from their hands without washing them first, ingesting the toxins into their still developing systems.^[3]

According to a study conducted by Northrup, 22% of infants and children are exposed to SHS/THS in their homes each year, comprising a major proportion of the 126 million nonsmokers exposed to harmful tobacco products annually.^[4]

Though research is limited, there are many harmful health effects that have been linked to THS exposure. THS has the potential to impair wound healing by altering the body’s natural anti-inflammatory response, remodel respiratory structure due to increased

Third-hand smoke has also been tested in various cell assays. THS exposure by cells have been shown to lead to the observation of DNA strand breaks, inhibition of proliferation, and cell death. Acrolein has shown to be a particularly potent third-hand smoke gas.[9]

A study led by Ashley Merianos, a tobacco researcher at the University of Cincinnati, revealed that in homes where children live, surfaces were contaminated with nicotine and the tobacco-specific carcinogen NNK. This was observed even in homes with voluntary indoor smoking bans, highlighting the persistent nature of THS pollutants. The study revealed higher levels of NNK and nicotine in lower-income households and homes who do not ban indoor smoking.^[10]

Chemical composition and reservoirs

Third-hand smoke and its components have been detected in a variety of indoor environments. The possibility of nitrosamine formation on vehicular surfaces was identified via the spraying of "high but reasonable" levels of nitrous acid (about 4–12 times the levels typically found in homes) onto cellulose substrates and wiping surfaces in a vehicle that had experienced heavy smoking.^[2] Similar results were found when cellulose substrates were kept (without wiping) in the same vehicle for three days when smoking occurred.^[2] Additionally, the persistence of various third-hand smoke components was quantified on wool, cotton, and polyester fibers^[11] with THS the most persistent on wool and least persistent on polyester. Washing clothing without detergent was found to remove some THS, though a substantial amount remained after standard laundering.^[11]

Because of the growing resolving power and improved detection limits of analytical instruments, studies have been able to demonstrate the transport of THS into other spaces via various media. For instance, third-hand smoke signatures have been detected in particles, which can effectively transport such compounds between indoor and outdoor air.^[12][13] Additionally, both gas-phase and aerosol-phase compounds linked to third-hand smoke were detected and quantified in a non-smoking movie theater, possibly via moviegoers' clothes and breath.^[14]

Environmental tobacco smoke can oxidize with environmental nitrous acid to create carcinogenic tobacco-specific

Smoking rates in the United States have fallen considerably from a high of 42.4% in 1965 to around 17.8% in 2016. But the downward trend is slowing and it is estimated that 23% to 42% of adults in America with low education or living in poverty still smoke. This exposes millions of nonsmokers, many of which are children.[4]

Awareness campaigns for THS are steadily growing in number and primarily focus on the health risks for young children. A 2014 study published in Pediatrics demonstrated that parents are more likely to attempt to quit smoking if they become convinced that third-hand smoke is harmful to children and are more likely to have smoke-free home and car policies if they are aware of the dangers of third-hand smoke. It was recommended for parents to safeguard their children by ensuring they have a smoke-free zone. One such way recommended for smokers to protect family, friends and others is by smoking outside and showering and changing clothes before coming into contact with others.^[18] However, research has shown that parents who are heavy smokers (> 10 cigarettes per day) are less likely to believe that third-hand smoke is harmful to children.^[19] Third-hand smoke is one of the issues promoting indoor smoking bans, especially supported by performers such as musicians, who are forced to bring third-hand smoke contamination into their homes through contaminated instruments and cases.

References