Impacts of Air Cleaners on Indoor Air Quality in Residences Impacted by Wood Smoke

Abstract

Residential wood combustion is an important source of ambient air pollution, accounting for over 25% of fine particulate matter (PM2.5) emissions in Canada. In addition to these ambient contributions, wood smoke pollutants can enter the indoor environment directly when loading or stoking stoves, resulting in a high potential for human exposure. A study of the effectiveness of air cleaners at reducing wood smoke-associated PM2.5 of indoor and outdoor origin was conducted in 31 homes during winter 2009-10. Day 1, the residents' wood burning appliance operated as usual with no air cleaner. Days 2 and 3, the wood burning appliance was not operational and the air cleaner was randomly chosen to operate in "filtration" or "placebo filtration" mode. When the air cleaner was operating, total indoor PM2.5 levels were significantly lower than on placebo filtration days (p = 0.0001) resulting in a median reduction of 52%. There was also a reduction in the median PM2.5 infiltration factor from 0.56 to 0.26 between these 2 days, suggesting the air cleaner was responsible for increased PM2.5 deposition on filtration days. Our findings suggest that the use of an air cleaner reduces exposure to indoor PM2.5 resulting from both indoor and ambient wood smoke sources.

The impacts of traffic-related and woodsmoke particulate matter on measures of cardiovascular health: a HEPA filter intervention study

“…These results are in agreement with a number of other studies that have demonstrated consistent reductions in indoor PM 2.5 with HEPA filtration 35 36. Unlike some previous studies, we did not observe any relationships between PM 2.5 and RHI.…”

Indoor human exposure to size-fractionated aerosols during the 2015 Southeast Asian smoke haze and assessment of exposure mitigation strategies

“…Few studies have assessed the effectiveness of using air cleaners to improve IAQ during smoke haze episodes, based on a reduction of the indoor PM loading [35,41]. Nevertheless, the effectiveness of these devices in reducing human exposure and the associated potential health risks based on the toxic elemental composition of PM indoors remains largely unknown.…”

“…Nevertheless, the effectiveness of these devices in reducing human exposure and the associated potential health risks based on the toxic elemental composition of PM indoors remains largely unknown. Additionally, previous studies reported in the literature [35,41] have been carried out under mid-latitude environmental conditions and thus are not applicable to tropical climatic conditions in SEA, where the smokehaze-impacted PM has unique physico-chemical characteristics [4,5,21,25].…”

A comparison of four receptor models used to quantify the boreal wildfire smoke contribution to surface PM<sub>2.5</sub> in Halifax, Nova Scotia during the BORTAS-B experiment

“…high factor loadings of Al, Si, Ca and Fe are indicative of crustal re-entrained material (Song et al, 2006;Hopke, 1991;Gibson et al, 2013b). Many studies use levoglucosan (1,6-anhydro-β-D-glucopyranose) as an unambiguous chemical tracer of wildfire and residential woodsmoke (Gibson et al, 2010;Ward et al, 2012;Simoneit et al, 1999;Wheeler et al, 2014). Levoglucosan is derived from cellulose burning at temperatures greater than 300 • C (Simoneit et al, 1999;Ward et al, 2006a).…”