Children who grow up on farms have a lower risk of developing asthma, and now it seems that may be due to microbes that can be in urban homes as well
Source:
https://www.newscientist.com/article/2206654-microbes-from-farms-may-protect-children-from-asthma-even-in-cities/?utm_campaign=RSS%7CNSNS&utm_source=NSNS&utm_medium=RSS&utm_content=home