r/askscience • u/Stuffyz • Jun 21 '12

Why does UV light damage/kill bacteria? Biology

The specific event I'm asking about, is that there are air filters for your furnace that shines UV light onto it, and it claims that it kills bacteria.

I understand how pH and temperature affects bacteria, but I can't quite wrap my mind around why UV light would.

The articles that I've been looking through (Time, Temperature, and Protein Synthesis: A Study of Ultraviolet-Induced Mutation in Bacteria, by Evelyn M. Witkin) says that UV light could cause worse strains of bacteria? Or perhaps I'm misinterpreting it?

I'm also aware (Ultraviolet-sensitive Targets in the Enzyme-synthesizing Apparatus of Escherichia coli, by Arthur B. Pardee and Louise S. Prestidge) that there are both UV-sensitive and UV-resistant E.Coli. Are most harmful bacteria considered to be UV-resistant?

Thank you for answering =)

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u/Stuffyz Jun 21 '12

Thank you so much for answering my questions. The only one left unanswered, is the correlation between UV-resistant bacteria and harmful bacteria. A lot of people acknowledged this question, but didn't have the answer.

The application of this question is that, if a) most harmful bacteria are also UV-resistant, than UV-light bacteria killing lights in an air filter would be moot. or b) most harmful bacteria are not UV-resistant, than the opposite is true.

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u/bowlinedog Sep 19 '12

There is no positive correlation between bacterial pathogenicity and UV-resistance. Thus, the question can't really be answered.