I find myself in the unaccustomed position of quoting the Jewish Press. But an interesting article by David Berger discusses a psak halachah "formulated by Rav Dovid Feinstein shlita and signed by Rav Yosef Shalom Elyashiv shlita and Rav Pinchas Sheinberg shlita" which confirms that in NY one should not drink tap water. In exceptionally respectful language, he suggests that this is an absurdity. [It is, IMHO, another example of the tendency to use halachah and other mechanisms of control to restrict more and more the ability of ordinary people to observe Judaism, restricting it to a smaller and smaller elite.]
But what about air? There are all sorts of organisms (and even the occasional insect) in air. Jains - an India-based religion with a reported 4m adherents worldwide - have a principle of faith called 'Ahimsa:non violence in all parts of a person -- mental, verbal and physical....... Committing an act of violence against a human, animal, or even vegetable generates negative karma which in turn adversely affects one's next life." Very observant Jains wear a mask over their mouth and nose the whole time in order to avoid inadvertantly swallowing or harming an airborne entity. Perhaps we should now think of doing the same. Orders for shaatnez-free masks should be sent via the blog. Cash only, please.