Engineering interns, Nick Murray (University of Dayton) and Jesse Andres (Oregon State University), have been working for about a month with smoke catching filters trying to ‘zero out’ emissions of PM 2.5. So far the PM emissions have been reduced from around 10mg/minute to around 3mg/minute. A $6 furnace filter catches a lot of the larger than 0.3 micron particles before they go up the chimney. We have better filters and hope that they will reduce smoke closer to ‘zero’. Some filters are washable and the idea is that filtering might join adding chimneys to cooking stoves, more complete combustion, increased ventilation, etc. as possible health protecting interventions. Filtering is commonplace in industrial applications and may also be cost effective on a much smaller scale. We’ll see!