Diana E. Hun

Formaldehyde in residences: long‐term indoor concentrations and influencing factors

UNLABELLED Chronic human exposure to formaldehyde is significantly increased by indoor sources. However, information is lacking on why these exposures appear to persist in older homes with aging sources. We use data from the Relationships of Indoor, Outdoor, and Personal Air study to evaluate 179 residences, most of which were older than 5 years. We assess the dependence of indoor formaldehyde concentrations (C(in)) on building type and age, whole-house air exchange rate, indoor temperature, and seasonal changes. Indoor formaldehyde had mean and median concentrations of 17 ppb, and primarily originated from indoor sources. The factors we analyzed did not explain much of the variance in C(in), probably because of their limited influence on mechanisms that control the long-term release of formaldehyde from aging pressed-wood products bound with urea-formaldehyde (UF) resins. We confirmed that the mitigating effects of ventilation on C(in) decrease with time through the analysis of data for new homes available in the literature, and through models. We also explored source control strategies and conclude that source removal is the most effective way to decrease chronic exposures to formaldehyde in existing homes. For new homes, reducing indoor sources and using pressed-wood with lower UF content are likely the best solutions. PRACTICAL IMPLICATIONS Formaldehyde concentrations in homes due to indoor sources appear to persist throughout the lifetime of residences. Increases in ventilation rates are most effective in decreasing indoor concentrations in new homes where formaldehyde levels are high or when homes are tight. Consequently, other alternatives need to be promoted such as decreasing the amount of pressed-wood products with urea-formaldehyde (UF) resins in homes or reducing the UF content in these materials.

Cancer Risk Disparities between Hispanic and Non-Hispanic White Populations: The Role of Exposure to Indoor Air Pollution

Background Hispanics are the fastest growing minority group in the United States; however, minimal information is available on their cancer risks from exposures to hazardous air pollutants (HAPs) and how these risks compare to risks to non-Hispanic whites. Methods We estimated the personal exposure and cancer risk of Hispanic and white adults who participated in the Relationships of Indoor, Outdoor, and Personal Air (RIOPA) study. We evaluated 12 of the sampled volatile organic compounds and carbonyls and identified the HAPs of most concern and their possible sources. Furthermore, we examined sociodemographic factors and building characteristics. Results Cumulative cancer risks (CCRs) estimated for Hispanics (median = 519 × 10−6, 90th percentile = 3,968 × 10−6) and for whites (median = 443 × 10−6, 90th percentile = 751 × 10−6) were much greater than the U.S. Environmental Protection Agency (EPA) benchmark of 10−6. Cumulative risks were dominated by formaldehyde and p-dichlorobenzene (p-DCB) and, to a lesser extent, by acetaldehyde, chloroform, and benzene. Exposure to all of these compounds except benzene was primarily due to indoor residential sources. Hispanics had statistically higher CCRs than did whites (p ≤ 0.05) because of differences in exposure to p-DCB, chloroform, and benzene. Formaldehyde was the largest contributor to CCR for 69% of Hispanics and 88% of whites. Cancer risks for pollutants emitted indoors increased in houses with lower ventilation rates. Conclusions Hispanics appear to be disproportionately affected by certain HAPs from indoor and outdoor sources. Policies that aim to reduce risk from exposure to HAPs for the entire population and population subgroups should consider indoor air pollution.

Home energy-efficiency retrofits.

In the February 2011 issue of EHP, Manuel (2011) took an important look at some potential adverse health implications of home energy retrofits. Here, we further discuss the complexity of possible indoor environmental concerns and encourage incorporation of comprehensive homeowner education campaigns in weatherization programs. The reduction of air infiltration by air sealing is a common energy retrofit measure (McCold et al. 2008). Several field studies of weatherized homes have reported average reductions in air leakage of 13–40% (Berry and Brown 1994; Judkoff et al. 1988), although the impact of weatherization on actual air exchange rates and indoor pollutant concentrations is poorly understood. Moreover, studies have seldom evaluated the effects of weatherization on low-income groups or vulnerable populations (e.g., asthmatic or elderly), although occupants in low-income residences are at higher risk for many indoor environmental hazards (Evans and Kantrowitz 2002), and some population subgroups may also be disproportionately affected by indoor air pollution (Hun et al. 2009). Although some research exists on the impact of weatherization on indoor concentrations of combustion products, radon, and moisture, other indoor pollutants deserve attention. For example, Logue et al. (2011) identified nine priority indoor air pollutant hazards in U.S. residences, which, among others, have been associated with a wide range of both chronic and acute health effects (e.g., benzene, 1,4-dichlorobenzene, formaldehyde, naphthalene, particulate matter < 2.5 µm in aerodynamic diameter). Moreover, reducing air exchange rates in residences will likely increase indoor concentrations of reactive pollutants and the probability of chemical reactions occurring between them indoors (Weschler and Shields 2000), generating by-products associated with respiratory symptoms and asthma, such as low-molecular-weight aldehydes, dicarbonyls, and secondary organic aerosols (Jarvis et al. 2005). On the other hand, reductions in air infiltration should decrease penetration of outdoor pollutants, which is of particular importance in traditionally leakier low-income households (Chan et al. 2005) in neighborhoods with high outdoor air pollution. Thus, we urge the environmental health community to investigate the net effects of weatherization on a wide variety of indoor and outdoor pollutants and health outcomes. Implementation of home energy retrofits also creates an opportunity to incorporate innovative, engaging homeowner education strategies to reduce both energy consumption and indoor environmental risks. Occupant behavior has a major influence on both energy consumption (Allcott and Mullainathan 2010) and indoor exposures to pollutants (Meng et al. 2005). Furthermore, many indoor air quality risks can be mitigated with relatively simple home behavior practices, such as using exhaust fans, avoiding toxic cleaning chemicals, and using appropriate air cleaners (Brugge et al. 2003). However, we have learned from research on household energy consumption that educational materials alone usually fail to alter behaviors (Charles 2009). Greater energy savings from home retrofits could be achieved by complementing homeowner education campaigns with regular feedback on energy use and economically motivational programs (Peschiera et al. 2010). Additionally, home walkthroughs with trained building specialists can identify energy-inefficient behaviors and appliances in conjunction with potential indoor environmental hazards. These and other behavior-change strategies to promote green and healthy housing should be made available to weatherization programs across the country, and their effectiveness should be assessed. Because home weatherization is currently a priority of the federal government, this is a crucial time to address these fundamental research questions and implement the findings nationwide.

High Performance Window Retrofit

The US Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE) and Traco partnered to develop high-performance windows for commercial building that are cost-effective. The main performance requirement for these windows was that they needed to have an R-value of at least 5 ft2 F h/Btu. This project seeks to quantify the potential energy savings from installing these windows in commercial buildings that are at least 20 years old. To this end, we are conducting evaluations at a two-story test facility that is representative of a commercial building from the 1980s, and are gathering measurements on the performance of its windows before and after double-pane, clear-glazed units are upgraded with R5 windows. Additionally, we will use these data to calibrate EnergyPlus models that we will allow us to extrapolate results to other climates. Findings from this project will provide empirical data on the benefits from high-performance windows, which will help promote their adoption in new and existing commercial buildings. This report describes the experimental setup, and includes some of the field and simulation results.

Priorities in indoor environmental science and health, as students see them

In a recent Indoor Air editorial (Volume 19, Issue 4, 2009), editor Jan Sundell wrote Indoor Air as a journal, as well as indoor air as a science, will die unless we start to co-operate, as Indoor Air and the society behind it, ISIAQ, are all aboutmultidisciplinary science! Howdire! Whether we consider deleterious effects in complex modern buildings or in rudimentary indoor systems in the developing world, indoor environments are fraught with human health hazards. Our highest goal, then, should not be to recruit lifelong indoor environmental scientists and engineers, but rather to clearly define human health challenges that take root in indoor environments and engage the expertise of teams and individuals from relevant disciplines to address them. Thus, while agreeing with Sundell s quote, we propose an alternate diction: Indoor environmental science and health research will flourish and progress when members from multiple disciplines collaborate and work toward common goals. Multiple disciplines cannot force common goals, yet solutions to problems in our field naturally encourage collaboration. The research questions in our field benefit from the inclusion of specialists from many disciplines, even if they do not focus entirely on indoor environments. Perhaps our field would further prosper by outcome-driven projects relying on many different outside specialists who would come to know the nature of our work in bits and pieces, rather than by convincing a few small groups of researchers to devote their careers to indoor environmental studies. In July 2009, with these collaborative goals in mind, we, the student members of a National Science Foundation (NSF) Integrative Graduate Education and Research Traineeship (IGERT) program in Indoor Environmental Science and Engineering at the University of Texas at Austin gathered to discuss research priorities in our field and to highlight some impending grand challenges we face as emerging indoor environmental scientists, but also as members of a larger, environmentally concerned scientific community. We produced the following list of priorities fromanovel, and previously unpublished, perspective: that of students.

Editorial: Priorities in indoor environmental science and health, as students see them: Editorial

In a recent Indoor Air editorial (Volume 19, Issue 4, 2009), editor Jan Sundell wrote Indoor Air as a journal, as well as indoor air as a science, will die unless we start to co-operate, as Indoor Air and the society behind it, ISIAQ, are all aboutmultidisciplinary science! Howdire! Whether we consider deleterious effects in complex modern buildings or in rudimentary indoor systems in the developing world, indoor environments are fraught with human health hazards. Our highest goal, then, should not be to recruit lifelong indoor environmental scientists and engineers, but rather to clearly define human health challenges that take root in indoor environments and engage the expertise of teams and individuals from relevant disciplines to address them. Thus, while agreeing with Sundell s quote, we propose an alternate diction: Indoor environmental science and health research will flourish and progress when members from multiple disciplines collaborate and work toward common goals. Multiple disciplines cannot force common goals, yet solutions to problems in our field naturally encourage collaboration. The research questions in our field benefit from the inclusion of specialists from many disciplines, even if they do not focus entirely on indoor environments. Perhaps our field would further prosper by outcome-driven projects relying on many different outside specialists who would come to know the nature of our work in bits and pieces, rather than by convincing a few small groups of researchers to devote their careers to indoor environmental studies. In July 2009, with these collaborative goals in mind, we, the student members of a National Science Foundation (NSF) Integrative Graduate Education and Research Traineeship (IGERT) program in Indoor Environmental Science and Engineering at the University of Texas at Austin gathered to discuss research priorities in our field and to highlight some impending grand challenges we face as emerging indoor environmental scientists, but also as members of a larger, environmentally concerned scientific community. We produced the following list of priorities fromanovel, and previously unpublished, perspective: that of students.

Editorial: Priorities in indoor environmental science and health, as students see them

In a recent Indoor Air editorial (Volume 19, Issue 4, 2009), editor Jan Sundell wrote Indoor Air as a journal, as well as indoor air as a science, will die unless we start to co-operate, as Indoor Air and the society behind it, ISIAQ, are all aboutmultidisciplinary science! Howdire! Whether we consider deleterious effects in complex modern buildings or in rudimentary indoor systems in the developing world, indoor environments are fraught with human health hazards. Our highest goal, then, should not be to recruit lifelong indoor environmental scientists and engineers, but rather to clearly define human health challenges that take root in indoor environments and engage the expertise of teams and individuals from relevant disciplines to address them. Thus, while agreeing with Sundell s quote, we propose an alternate diction: Indoor environmental science and health research will flourish and progress when members from multiple disciplines collaborate and work toward common goals. Multiple disciplines cannot force common goals, yet solutions to problems in our field naturally encourage collaboration. The research questions in our field benefit from the inclusion of specialists from many disciplines, even if they do not focus entirely on indoor environments. Perhaps our field would further prosper by outcome-driven projects relying on many different outside specialists who would come to know the nature of our work in bits and pieces, rather than by convincing a few small groups of researchers to devote their careers to indoor environmental studies. In July 2009, with these collaborative goals in mind, we, the student members of a National Science Foundation (NSF) Integrative Graduate Education and Research Traineeship (IGERT) program in Indoor Environmental Science and Engineering at the University of Texas at Austin gathered to discuss research priorities in our field and to highlight some impending grand challenges we face as emerging indoor environmental scientists, but also as members of a larger, environmentally concerned scientific community. We produced the following list of priorities fromanovel, and previously unpublished, perspective: that of students.