Cannabis smoke from bongs worse than cigarette for passive smokers, says study  

London

Cigarette smoking is injurious to health. But what is more dangerous? The answer is secondhand cannabis smoke from a bong, as per researchers.  

The study has been published in the journal ‘JAMA Network Open’ on Wednesday.  

The concentrations of fine particulate matter (PM2.5) generated during social cannabis bong smoking in a home to which a non-smoking resident may get exposed were high compared to background levels, and that PM2.5 decayed only gradually after smoking ceased, the authors of the study found.  

After just 15 minutes of smoking, average PM2.5 was more than twice the threshold set by Environmental Protection Agency (EPA) for hazardous air quality.  

The authors, who are from the University of California, Berkeley School of Public Health, wrote bong smoking “is not safe.”   

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“Decades ago, many people thought secondhand tobacco smoke (SHTS) presented no health risk to non-smokers. Scientific research since then changed this perception and led to smoke-free environments. Incorrect beliefs about secondhand cannabis smoke (SHCS) safety promote indoor cannabis smoking,” they said.   

“Non-smokers are exposed to even higher concentrations of SHCS materials during ‘hot-boxing,’ the popular practice in which cannabis smokers produce high volumes of smoke in an enclosed environment. This study’s findings suggest SHCS in the home is not safe and that public perceptions of SHCS safety must be addressed.”  

To reach a conclusion, the researchers measured the Environmental Health Sciences Division members’ levels of PM2.5 before, during and after eight cannabis smoking sessions in a room.   

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The home cannabis bong smoking hiked PM2.5 from background levels by around 100-fold to 1,000-fold for six of eight sessions. In the other two sessions, background levels were high and it spiked PM2.5 by more than 20-fold.  

In first 10 minutes, mean PM2.5 concentrations increased to 410 micrograms and 570 micrograms after 15 minutes. After 30 minutes, level was 1,000 micrograms, and it reached 2,500 micrograms in one session.   

(With inputs from agencies)