Dr Noel Aquilina from the Department of Chemistry is an affiliate researcher of the Thirdhand Smoke Consortium of the University of California.
Following decades of educational campaigns, we might be asking why do people still smoke cigarettes in this day and age? Most probably the five most important factors are peer pressure, parental and media influence, genetic and stress factors.
Media and somewhat peers have always depicted smoking to be a “cool” social habit, generally to be nicely accompanied with a drink. Parental relationships with their children, at the early development stages greatly influence the approach of children to smoking in the future. Non-smokers tend to instill and constantly communicate with their children how unhealthy, intolerable, and most importantly, how detrimental smoking is. Children with smoking parents tend to have the opposite exposure, smoking habits would be normalized in their lives and generally lead them to the same path. Although their might be some genetic predisposition, this is not automatically passed on. In a fast-paced society, some people try to stun their daily stresses by starting smoking.
All this leads to short and long-term added medical problems, but there should be reasons why it is difficult to quit smoking. These are generally three. Nicotine, mental triggers and social situations.
Nicotine is the major, highly addictive agent of cigarettes, the real trap and only 4-7% of smokers manage to quit abruptly and unaided because of withdrawal symptoms. Why do some mental triggers make it harder to stop smoking? Smokers tend to follow routine patterns like smoking while driving, with a coffee, after dinner or whenever they crave for a smoke. Other mental triggers could be that smoking may alleviate stressful or anxious situations.
From the scientific perspective, which are the new aspects of the malaise created by smoking? The Thirdhand Smoke Consortium is trying to address this. Dr Noel Aquilina, one of the very few Europeans involved in this endeavour, as an atmospheric chemist and exposure scientist led three local projects which were reported in the THS consortium’s newsletter.
In summary, the first project addressed the need to understand the contribution of tobacco smoking in particulate matter that we constantly inhale. The major finding has been that after about 30 years, nicotelline, a marker for tobacco-derived particulate matter in particulate matter collected in eleven cities around the world has been confirmed. The higher smoking prevalence (as in Malta, 20%) the higher the contribution. This finding led to the search for the most potent lung carcinogen derived from tobacco, NNK (4-(Methylnitrosamino)-1-(3-Pyridyl)-1-Butanone). Similarly, but in a certain way, surprisingly NNK was found almost in all samples of airborne dust of different size ranges. We are inhaling a small portion of this carcinogen, all the time, independently if we are smokers or not. In indoor environments, where smoking still occurs, the build-up of NNK can be substantial and very dangerous.
This worrying notion led to the second project. What about our local settled house dust? At least three-day old samples of settled house dust were collected from all over Malta. The important takeaways were that all dust samples contained nicotine, nicotelline and NNK, irrespective of the geographic areas, with levels much higher in smokers’ homes. These pollutants manage to build up in relatively “fresh” dust. The long-term health implications of continuously inhaling this resuspended dust while we are in our homes and the risk for toddlers ingesting dust with this potent carcinogen are still being researched. Our levels tend to be lower than US samples, because we have tiled floors and not so much carpeted floors. This means we have less sinks for these pollutants and wet mopping helps to reduce their availability.
The third project was associated with the first biomarker study associated with secondhand and thirdhand tobacco smoke exposure in 9-11 year old school children in Malta. Urine samples collected from 174 students, attending five Government schools in Malta participated in this project. In our body nicotine changes to cotinine (COT) and trans-3’-hydroxycotinine (3HC), these are very good indicators of secondhand smoke exposure. The exposure to NNK leads to the body changing it to NNAL (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol) which happens to be an equally potent carcinogen and indicator of thirdhand smoke. Shocking information emerging from this study could be summarised as follows.
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Only 4.6% of the participating children were not exposed to enough tobacco smoke to be detected in their bodies.
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When parents answered questionnaires about exposure to tobacco smoke at home, 72.4% indicated there was no smoking at home which might sound encouraging, yet COT, 3HC and NNAL were measurable in 99.4%, 95.4% and 98.3% of the children respectively. This is a clear indicator of tobacco smoke exposure occurring in the children’s social circles, away from home.
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For the parents reporting smoking at home (27.6%), 11% of the children had a history of asthma and had COT, 3HC and NNAL mean concentrations double compared to the non-asthmatic group.
The health implications of exposure to NNK and NNAL in children as they grow up is largely unknown. Similarly, almost none is known on the effects of continuous inhalation or ingestion of particulate matter contaminated with NNK and similar pollutants.