{"id":1214,"date":"2014-01-16T14:23:24","date_gmt":"2014-01-16T19:23:24","guid":{"rendered":"http:\/\/atipure.com\/store\/?post_type=avada_faq&p=1214"},"modified":"2026-04-04T12:43:51","modified_gmt":"2026-04-04T17:43:51","slug":"guidance-for-fine-particulate-matter-pm2-5-in-residential-indoor-air","status":"publish","type":"avada_faq","link":"https:\/\/atipure.com\/store\/?avada_faq=guidance-for-fine-particulate-matter-pm2-5-in-residential-indoor-air","title":{"rendered":"Guidance for Fine Particulate Matter (PM2.5) in Residential Indoor Air"},"content":{"rendered":"

\u00a0Background<\/b><\/p>\n

Fine particulate matter (PM2.5<\/sub>) is a general term for all small particles found in air measuring equal to or less than 2.5 \u03bcm in aerodynamic diameter. It is a complex mixture whose constituents vary in size, shape, density, surface area, and chemical composition (Health Canada and Environment Canada 1999; US EPA 2009). In 1987, Health Canada published Exposure Guidelines for Residential Indoor Air Quality, which set maximum acceptable long- and short-term exposure ranges for PM2.5<\/sub>\u00a0in homes. These guidelines are being revised to reflect the most up-to-date science on the health effects and residential exposure for PM2.5<\/sub>.<\/p>\n

Exposure<\/b><\/p>\n

Indoor PM2.5<\/sub>\u00a0is composed of indoor-generated PM2.5\u00a0<\/sub>from sources such as smoking, cooking, and cleaning, and PM2.5<\/sub>\u00a0that has infiltrated from the outside. In studies conducted by Health Canada in different Canadian cities, average indoor PM2.5<\/sub>concentrations were less than 15 \u00b5g\/m3<\/sup>\u00a0in homes without smokers, and less than 35 \u00b5g\/m3<\/sup>\u00a0in homes with smokers (Health Canada 2010). In general, indoor PM2.5<\/sub>\u00a0levels were lower than outdoor concentrations measured directly outside the home, except in homes with smokers.<\/p>\n

Health Effects<\/b><\/p>\n

Outdoor PM2.5<\/sub>, as measured at area monitoring stations, has been shown in a large number of studies to be strongly associated with cardiovascular and respiratory mortality and morbidity endpoints (Health Canada and Environment Canada 1999; WHO 2005; US EPA 2009). There is no recognized threshold of health effects for outdoor PM2.5<\/sub>regardless of where exposure occurs (i.e., indoors or outdoors), and there is evidence that adverse health effects occur at current levels of exposure.<\/p>\n

A much smaller number of studies have investigated the relationship between indoor PM2.5<\/sub>\u00a0and health. There is some evidence for a relationship between indoor PM2.5<\/sub>\u00a0levels and declines in lung function and increases in exhaled nitric oxide, a marker of airway inflammation, in asthmatic children (Koenig et al. 2003; Delfino et al. 2004; Koenig et al. 2005; Trenga et al. 2006).\u00a0 However, changes in exhaled nitric oxide were more strongly associated with outdoor PM2.5<\/sub>\u00a0than indoor PM2.5<\/sub>\u00a0(Koenig et al. 2003; Koenig et al. 2005; Allen et al. 2008). Associations between indoor PM2.5<\/sub>\u00a0and subtle changes in markers of cardiovascular disease have also been observed in older adults (Delfino et al. 2008; Liu et al. 2009; Allen et al. 2011).<\/p>\n

Guidance<\/b><\/p>\n

The acceptable long- and short-term exposure ranges established in the 1987 exposure guidelines should be rescinded and replaced with this new guidance focusing on indoor source control to minimize long-term exposure to PM2.5<\/sub>\u00a0indoors.<\/p>\n

Indoor levels of PM2.5<\/sub>\u00a0should be kept as low as possible, as there is no apparent threshold for the health effects of PM2.5<\/sub>. It is impossible to entirely eliminate PM2.5<\/sub>indoors, as among its sources are essential and everyday activities, such as cooking and cleaning, as well as infiltration from outdoor sources, over which residents have little or no control. However, any reduction in PM2.5<\/sub>\u00a0would be expected to result in health benefits, especially for sensitive individuals, such as those with underlying health conditions, the elderly or children.<\/p>\n

The focus should be on reducing indoor sources over which homeowners and residents have some degree of control. The main recommended strategies to reduce exposure to the major sources of indoor-generated PM2.5<\/sub>\u00a0are:<\/p>\n