Letter Re: Emergency Shelter Air Filtration

Hey Jim,
Just a couple of articles [over at the Alpha Rubicon site] that you might find interesting:
Safe Room Fan
HEPA Filter
Regards, – S.C.

JWR Replies: For any SurvivalBlog that might have overlooked it at my Links page, I highly recommend the wide variety of practical free references available at the Alpha Rubicon web site.