Reducing indoor air pollutants with air filtration units in wood stove homes.
BACKGROUND
Biomass burning has been shown to be a major source of poor indoor air quality (IAQ) in developing and higher income countries across the world. Specifically, wood burning for cooking and heating contributes to high indoor concentrations of fine (particles with aerodynamic diameters<2.5μm; PM2.5) and coarse (particles with aerodynamic diameters <10μm and >2.5μm; PMc) particulate matter. Endotoxin, predominantly found within the coarse fraction of airborne particulate matter, is associated with proinflammatory effects and adverse outcomes among susceptible populations. The aim of this study was to assess the efficacy of air filter interventions in reducing indoor PM2.5, PMc, and PMc-associated endotoxin concentrations in homes using a wood stove for primary heating.


RESULTS
Homes (n=48) were randomized to receive in-room air filtration units with either a high efficiency filter (i.e. active) or a lower efficiency fiberglass filter (i.e., placebo). The active filter intervention showed a 66% reduction in indoor PM2.5concentrations (95% CI: 42.2% to 79.7% reduction) relative to the placebo intervention. Both the active and the placebo filters were effective in substantially reducing indoor concentrations of PMc (63.3% and 40.6% average reduction for active and placebo filters, respectively) and PMc-associated endotoxin concentrations (91.8% and 80.4% average reductions, respectively).


CONCLUSIONS
These findings support the use of high efficiency air filtration units for reducing indoor PM2.5in homes using a wood stove for primary heating. We also discovered that using lower efficiency, lower cost filter alternatives can be effective for reducing PMc and airborne endotoxin in homes burning biomass fuel.
Center for Environmental Health Sciences, Department of Biomedical Sciences, University of Montana, Missoula, MT 59801, USA. Electronic address: Marcy1.mcnamara@umontana.edu.
Marcy L
ML
McNamara
RTI International, Research Triangle Park, NC, USA. Electronic address: jwt@rti.org.
Jonathon
J
Thornburg
Center for Environmental Health Sciences, Department of Biomedical Sciences, University of Montana, Missoula, MT 59801, USA. Electronic address: Erin.Semmens@umontana.edu.
Erin O
EO
Semmens
School of Public and Community Health Sciences, University of Montana, Missoula, MT 59801, USA. Electronic address: Tony.Ward@umontana.edu.
Tony J
TJ
Ward
Center for Environmental Health Sciences, Department of Biomedical Sciences, University of Montana, Missoula, MT 59801, USA. Electronic address: curtis.noonan@umontana.edu.
Curtis W
CW
Noonan
D000393:Air Pollutants / Q000032:analysis; D016902:Air Pollution, Indoor / Q000517:prevention & control*; D005374:Filtration / Q000295:instrumentation*; D006361:Heating; D006798:Housing; D052638:Particulate Matter / Q000032:analysis; D011897:Random Allocation; D014934:Wood
D000393:Air Pollutants; D052638:Particulate Matter
Air filter; Biomass; Coarse; Endotoxin; Particulate matter; Residential