New research coming out of Finland, published in the Proceedings of the National Academy of Sciences, shows that a lack of contact with nature, and the variety of beneficial bacteria there, may be leading to more city-dwellers developing allergies and asthma.
Report co-author Ilkka Hanski told BBC News:
There are microbes everywhere, including in the built environment, but the composition is different between natural environments and human-built areas. The microbiota in natural environments is more beneficial for us. They are important for...the normal development of the immune system.
In particular the gammaproteobacteria, found with greater prevalence in forests and agricultural land than in the built environment, had a particular important function:
Our study showed that the more you had of this particular gammaproteobacteria on your skin then you had a immunological response which is known the suppress inflammatory responses to pollen, animals, etc.
As for what to do about this, the authors emphasize the importance of parks and other green spaces within the urban environment.
Read more from BBC News, and the original research: Environmental biodiversity, human microbiota, and allergy are interrelated.
All of which is to say, get outside, into nature as often as possible. Don't be a germophobe and don't seal yourself into buildings. Nature is good for you.