Smoking Marijuana With A Water Bong Doesn’t Effectively Filter Compounds From Smoke, Study Suggests
For decades, marijuana consumers have debated whether using a bong, where smoke is pulled through water before inhalation, is any safer than inhaling smoke from a joint. Conventional wisdom has long held that water filtration makes for a cleaner, less harmful consumption experience.
But a new study, by authors affiliated with the University of Wisconsin-Madison and in Thailand, concludes that “bong water does not seem to significantly filter out any compound from the smoke.”
For the study, researchers analyzed the chemical makeup of smoke from three popular cannabis strains—Bubble Gum, Silver Haze and Hang Over OG—when consumed through both joints and bongs. Using gas chromatography-mass spectrometry (GC-MS), a highly sensitive apparatus that identifies chemical compounds by their molecular weight, they looked for differences in the final combusted smoke.
The results for both consumption methods were nearly identical. Bong water didn’t completely remove any of the detected compounds in the range the instrument could measure. The study found no compounds that appeared only in joint smoke and not in bong smoke, suggesting the water did not fully capture any components within the tested size range.
The researchers note in the paper, published as a pre-print on bioRxiv, that their methods couldn’t capture larger particles, aerosols or metals—in other words, things that water might catch.
Still, the findings cast doubt on the idea that a bong meaningfully reduces exposure to harmful chemicals.
“Although the effectiveness of the filtration of the bong is not clear, this study sheds light on the chemical composition of cannabis smoke,” they concluded.
The study also shows promise for compounds detected in higher concentrations. They note that the prevalence of β-cis-Caryophyllene, which was consistently present in the highest quantities, suggests “possible physiological importance despite limited research compared to THC and CBD.” They added that the compound “has a potential anti-inflammatory, antibiotic, antioxidant, anticarcinogenic and local anesthetic activity.”