HEPA home furnace filter reduces PM2.5 emissions
There are a number of methods to reduce personal exposure to household air pollution associated with using biomass fuel for the daily cooking and heating taking place in nearly 40% of global households. These most commonly include 1.) Increasing ventilation rates, 2.) Installing a chimney and 3.) The use of cleaner fuels and cook stoves. A recent ARC paper available (free for a limited time) at:
investigates two less-commonly considered methods: 1) Reducing exposure through filtration and capture of PM2.5 and 2) Avoiding making emissions by using made charcoal and retained heat for cooking.
The smoke is pulled through the filter and less smoke exits the room
When cook stoves are operated inside an enclosure from which smoke is pulled through an inexpensive HEPA-type furnace filter before exiting to the outside, the personal exposure levels, room concentrations, and external pollution are reduced. To test this method, an enclosure was built from which a box fan pulled the air and PM2.5 through four different furnace filters. The rate of PM2.5 production (mg/min) exiting the filter was monitored with gravimetric measurement under a LEMS emissions hood during the high and low power phases of the Water Boiling Test 4.2.3 conducted on a biomass rocket stove with forced draft.
The average of seven baseline emissions tests with no filter was 7.5 mg/min of PM2.5. The average of seven tests using the highest quality furnace filter (3M 2200) was reduced to 1.5 mg/min and the difference was significant at 95% confidence. The use of retained heat to simmer dramatically reduced emissions of PM2.5 by burning the boil-phase-made-charcoal and using retained heat in the stove while 5 liters of covered water were simmered for 35 minutes.