A friend of mine was visiting a small college in Northern Vermont, and while there, was told that drinking carbonated beverages will attract mosquitoes due to the extra carbon dioxide (CO2) in the beverage. My friend, who is not a scientist, was rightly skeptical and asked me about this, as her intuition lead her to question whether there was a significant amount of CO2 in a typical can of soda. As a scientist who has spent my career not just as a college educator, but as a researcher in the physical and biological sciences, I was horrified by the complete lack of basic science & math education on the part of the original claimant.
So here are the facts:
1. A typical human exhales about 1kg of carbon dioxide per day, or 694 milligrams per minute (694 milligrams CO2/minute).
2. A 12 fluid ounce can of soda contains about 1.9 grams of carbon dioxide, or 1900 milligrams CO2.
So how long does it take a typical human to emit as much CO2 as is contained in a 12 fluid ounce can of soda? The calculation is easy, namely:
1900 milligrams CO2 / (694 milligrams CO2/minute) = 2.7 minutes
So guzzling a 12 fluid ounce can of soda in 3 minutes, and burping the CO2 all the while, would just double your CO2 emission rate during that time. Given that most people don't drink a can of soda that fast, nor emit the CO2 from the soda that fast, the "increase" in CO2 emission rate is less.
A major additional fact relevant to this issue is that CO2 alone does not attract mosquitoes. For mosquitoes to follow a CO2 trail, the trail also needs to contain steroids (animals emit from skin), octanol (animals emit in their breath) and/or other metabolic compounds such as uric & lactic acids indicating to the mosquito that the CO2 is coming from a suitable animal for it to feed upon. For example, there have been reports that drinking alcoholic beverages can increase human attractiveness to mosquitoes (Shirai et al., Journal of the American Mosquito Control Association 18, 91 (2002)), but the study size was too small to be statistically significant. From my computer search of the scientific literature, this alcohol attractiveness work has only been reproduced once, also with a very small study size (Lefevre et al., PLOS ONE 5, e9546 (2010) DOI: 10.1371/journal.pone.0009546) but in a manner which indicated that CO2 emission by the human subjects was not an issue.
Are You a Mosquito Magnet? (WebMD)
Mosquito Information Website (University of Florida)
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