Glad to see this paper on emission of bacteria by people is now available under Wiley’s “Open Access” option: Size-resolved emission rates of airborne bacteria and fungi in an occupied classroom – Qian – 2012
I am particularly glad since this one got a lot of media coverage and I think it is VERY important for the actual papers behind news stories be made available to the public. So – this is a few weeks late but better later than never.
Here are some of the news stories:
- You show up, and millions of microbes launch into the air
- People Stir Up Millions of Bacteria When Entering a Room: Study
- Your Presence Can Add 37 Mln Bacteria In A Room : Study
- Humans bring millions of bacteria to indoor spaces, study says
- UC Berkeley Bacteria Study: Research Shows Humans A Major Source …
- One Person Adds 37 Million Bacteria to a Room
- Humans bring millions of bacteria to indoor spaces, study says
and more
Image By Aimcotest (Own work) [CC-BY-SA-3.0 (www.creativecommons.org/licenses/by-sa/3.0) or GFDL (www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons.
The open access to the article is great! Thanks to the Sloan Foundation’s Paula Olsiewski for making it possible.
What are the implications of these findings for building scientists, building operators, and building occupants? What kind of behavioral changes, if any, does this suggest? What kinds of further research does it suggest?
The Practical Implications statement in the journal reads as follows:
“Practical Implications
Presented here are the ï¬rst size-resolved, per person emission rate estimates of bacterial and fungal genomes for a common occupied indoor space. The marked differences observed between total particle and bacterial size distributions suggest that size-dependent aerosol models that use total particles as a surrogate for microbial particles incorrectly assess the fate of and human exposure to airborne bacteria. The strong signal of human microbiota in airborne particulate matter in an occupied setting demonstrates that the aerosol route can be a source of exposure to microorganisms emitted from the skin, hair, nostrils, and mouths of other occupants.”
When considered together with the recent Kembel et al paper (ISMEJ, January 2012), is there any suggestion that improving typical building air filtration system performance might significantly affect exposure and alter community-acquired infection rates? I assume we still don’t know enough to answer that question. But it also seems that improved filtration of the particles in the relevant size range could reduce exposure. Or is there some additional work that could be done to advance our understanding of that question? If so, what is it? Is Sloan (or anyone) funding that type of work now?
Well, presumably one could change the filtration systems to target certain particle sizes. But who is to say if that is better? Exposure to other people’s microbes could be both bad and good (and likely mostly neither). The bad would be when someone else carries a pathogen or a microbe that has potential to alter their microbiome. The good would be when exposure to other people’s microbes has benefits, like stimulating the immune system, sampling microbial diversity, etc. I think the fact that microbes are flying off of people at high rates is simply the precursor to more specific studies of what the effect of these flying microbes are …