Issue link: https://hi.iaq.net/i/552698
IAQA 18th Annual Meeting & Indoor Environment and Energy Expo (IE3) The views and opinions herein are those of the volunteer authors and may not reflect the views and opinions of IAQA. The information is offered in good faith and believed to be reliable but it is provided without warranty, expressed or implied, as to the merchantability, fitness for a particular purpose or any other matter. Exposure to Indoor Allergens The most important indoor allergens are produced by the dust mites Dermatophagoidespteronyssinus (Der p 1, Der p 2) and Dermatophagoidesfarinae (Der f 1, Der f 2), cat (Fel d 1), dog (Can f 1), German cockroach (Bla g 1, Bla g 2), mouse (Mus m 1) and rat (Rat n 1). Sources of these indoor allergens include fecal particles, fur, saliva, urine, skin particles, and body fragments. Allergen-carrying particles generally settle onto surfaces with dust, but can become airborne, generally leading to exposure through inhalation. Over the years, several studies have been conducted to investigate the health risks associated with allergen exposure. Many of these studies have taken place in inner cities due to the high prevalence of asthma and allergic disease, and have identified exposure to cockroach allergens as a major risk factor in low income, urban housing environments. The National Cooperative Inner-City Asthma Study (NCICAS) reported that 85% of dust samples collected in children's bedrooms had detectable cockroach allergen (Rosenstreich et al. 1997). Subsequent studies found that 95% of NCICAS homes had detectable levels of mouse allergen, which even exceeded the prevalence of cockroach allergen (Phipatanakul et al. 2000). Recent and ongoing studies by various researchers now demonstrate that exposure to mouse allergen is far more ubiquitous than previously considered. This is the case not only in inner-city homes, but also in other urban and suburban homes and schools. Several studies reported significant levels of cockroach and mouse allergens in urban schools across the country, and in many cases the levels in school rooms were higher than those found in children's homes (Permaul et al. 2012. Chew et al. 2005. Sheehan et al. 2009). An urban study conducted in a Baltimore inner-city environment, where 150 asthmatic children were enrolled, received clinical assessments and had bedroom dust sampled and tested for allergens from cat, cockroach, dust mite, and mouse. The results showed that sensitization and exposure to both cockroach and mouse allergen was generally associated with worse asthma outcomes. In communities with high levels of both mouse and cockroach allergens, such as the Baltimore inner-city, mouse allergen was more strongly and consistently associated with poor asthma outcomes than cockroach allergen (Ahluwalia et al. 2013). Co-Exposure to Allergens and Air Pollutants In addition to allergens, many otherpotential components comprise indoor air, and it is important to consider the whole system with regard to air quality and the impact on occupant health. Many studies have linked exposure to pest allergens and various indoor pollutants to asthma symptoms, exacerbations, and acute care use in urban children with asthma. Such pollutants include second-hand smoke (Butz et al. 2011), particulate matter (McCormack et al. 2009), and nitrogen dioxide (Hansel et al. 2008). Another potential component of the indoor environment known to cause respiratory problems is endotoxin, a lipopolysaccharide found in the cell wall of gram-negative bacteria. Several studies have investigated the health effects of endotoxin exposure, but mostly as an isolated component. A recent study by Matsui et al. (2013) assessed airborne nicotine, endotoxin, and nitrogen dioxide (NO 2 ) to determine whether the respiratory effects of household endotoxin exposure are influenced by co-exposures to other common indoor pollutants. Results showed that both airborne nicotine and NO 2 concentrations modified the relationship between endotoxin and asthma outcomes: In the absence of nicotine, higher endotoxin levels were associated with less severe asthma outcomes. But in homes with detectable nicotine, higher endotoxin levels were associated with worse asthma