Particle concentrations and effectiveness of free-standing air filters in bedrooms of children with asthma in Detroit, Michigan

Abstract

Asthma can be exacerbated by environmental factors including airborne particulate matter (PM) and environmental tobacco smoke (ETS). We report on a study designed to characterize PM levels and the effectiveness of filters on pollutant exposures of children with asthma. 126 households with an asthmatic child in Detroit, Michigan, were recruited and randomized into control or treatment groups. Both groups received asthma education; the latter also received a free-standing high efficiency air filter placed in the child's bedroom. Information regarding the home, emission sources, and occupant activities was obtained using surveys administered to the child's caregiver and a household inspection. Over a one-week period, we measured PM, carbon dioxide (CO 2 ), environmental tobacco smoke (ETS) tracers, and air exchange rates (AERs). Filters were installed at midweek. Before filter installation, PM concentrations averaged 28 µg m −3 , number concentrations averaged 70,777 and 1,471 L −1 in 0.3-1.0 and 1-5 µm size ranges, respectively, and the median CO 2 concentration was 1,018 ppm. ETS tracers were detected in 23 of 38 homes where smoking was unrestricted and occupants included smokers and, when detected, PM concentrations were elevated by an average of 15 µg m −3 . Filter use reduced PM concentrations by an average of 69 to 80%. Simulation models representing location conditions show that filter air flow, room volume and AERs are the key parameters affecting PM removal, however, filters can achieve substantial removal in even "worst" case applications. While PM levels in homes with asthmatic children can be high, levels can be dramatically reduced using filters.

The feasibility of an air purifier and secondhand smoke education intervention in homes of inner city pregnant women and infants living with a smoker

“…Indoor PM 2.5 in our participant homes (baseline mean = 43 and median = 31 μg/m 3 ) was similar to other studies in Baltimore City (Eggleston et al, 2005; Butz et al, 2011; McCormack et al, 2009) as well as other U.S. cities that measured PM 2.5 in homes with a smoker (Du et al, 2011; Hunt et al, 2011; Wallace et al, 2003). Smoking indoors has been associated with PM 2.5 measurements that are 14–34 μg/m 3 higher than in nonsmoking homes (Du et al, 2011; Hunt et al, 2011; Wallace et al, 2003; Breysse et al, 2005), therefore providing a greater potential for exposure reduction among individuals living in smoking homes.…”

“…Smoking indoors has been associated with PM 2.5 measurements that are 14–34 μg/m 3 higher than in nonsmoking homes (Du et al, 2011; Hunt et al, 2011; Wallace et al, 2003; Breysse et al, 2005), therefore providing a greater potential for exposure reduction among individuals living in smoking homes. The EPA does not have indoor air quality standards, but 45% of our homes had baseline PM 2.5 concentrations that were higher than the recommended ambient annual mean of 35 μg/m 3 and 60% were higher than 25 μg/m 3 , which is the annual indoor standard set by the World Health Organization (WHO) (World Health Organization, 2005).…”

“…Education and counseling interventions to reduce SHS exposure have demonstrated varying success (Baxi et al, 2014), and trials utilizing indoor air purifiers have demonstrated their feasibility and sustained effectiveness in reduction of indoor air pollution in homes of children with asthma (Batterman et al, 2012; Du et al, 2011; Eggleston et al, 2005; Lanphear et al, 2011; Butz et al, 2011). Studies evaluating the health effects of air purifiers have shown that they may be beneficial in children with asthma (Eggleston et al, 2005; Lanphear et al, 2011; Butz et al, 2011) but the feasibility of these interventions in the homes of pregnant women and infants without chronic respiratory illnesses is unknown.…”

Measured performance of filtration and ventilation systems for fine and ultrafine particles and ozone in an unoccupied modern California house

“…A high performance filter in the forced air heating and cooling (HAC) system will remove particles when the system operates for thermal control and can be operated on a timer when no conditioning is needed. Filtration effectiveness has been investigated through measurement studies in homes (Batterman et al, 2012;Du et al, 2011;MacNeill et al, 2012;Noris et al, 2013;Spilak et al, 2014;Stephens and Siegel, 2013) and also via simulation studies that tend to focus on population-scale benefits (Azimi et al, 2014;MacIntosh et al, 2010;Zhao et al, 2015).…”

Indoor PM10 and its heavy metal composition at a roadside residential environment, Phitsanulok, Thailand

“…Exposure to PM occurs mainly indoors because people spend most of their time inside buildings, especially in their homes (Massey et al, 2013;Du et al, 2011;Yang Razali et al, 2015). Effects of inhaled aerosols depend on the specific chemical species, the concentration, the duration of exposure, and the site of deposition within the respiratory tract (Salma et al, 2002).…”