Formaldehyde levels in FEMA-supplied travel trailers, park models, and mobile homes in Louisiana and Mississippi

Formaldehyde and asthma: a plausibility?

Formaldehyde (FA) is a ubiquitous indoor air pollutant emitted from construction, consumer, and combustion-related products, and ozone-initiated reactions with reactive organic volatiles. The derivation of an indoor air quality guideline for FA by World Health Organization in 2010 did not find convincing evidence for bronchoconstriction-related reactions as detrimental lung function. Causal relationship between FA and asthma has since been advocated in meta-analyses of selected observational studies. In this review, findings from controlled human and animal exposure studies of the airways, data of FA retention in the respiratory tract, and observational studies of reported asthma applied in meta-analyses are analyzed together for coherence of direct association between FA and asthma. New information from both human and animal exposure studies are evaluated together with existing literature and assessed across findings from observational studies and associated meta-analyses thereof. Retention of FA in the upper airways is > 90% in agreement with mice exposure studies that only extreme FA concentrations can surpass trachea, travel to the lower airways, and cause mild bronchoconstriction. However, taken together, detrimental lung function effects in controlled human exposure studies have not been observed, even at FA concentrations up 4 ppm (5 mg/m3), and in agreement with controlled mice exposure studies. Typical indoor FA concentrations in public buildings and homes are far below a threshold for sensory irritation in the upper airways, based on controlled human exposure studies, to induce sensory-irritative sensitization nor inflammatory epithelial damage in the airways. Analysis of the observational heterogeneous studies applied in the meta-analyses suffers from several concomitant multifactorial co-exposures, which invalidates a direct association with asthma, thus the outcome of meta-analyses. The evidence of a direct causal relationship between FA and asthma is insufficient from an experimental viewpoint that includes retention data in the upper airways and controlled animal and human exposure studies. Taken together, a coherence of controlled experimental findings with individual observational studies and associated meta-analyses, which suffer from caveats, is absent. Further, lack of identified evidence of FA-IgE sensitization in both experimental studies and observational studies agrees with indoor FA concentrations far below threshold for sensory irritation. The assessment of experimental data with uncontrolled observational studies in meta-analyses is incompatible with a direct causal relationship between FA and asthma or exacerbation thereof due to lack of coherence and plausibility.

Research on the elimination of low-concentration formaldehyde by Ag loaded onto Mn/CeO2 catalyst at room temperature

Formaldehyde (HCHO) is one of the major air pollutants, and its effective removal at room temperature has proven to be a great challenge. In this study, an Ag/Mn/CeO2 catalyst for the catalytic oxidation of low-concentration HCHO at room temperature was prepared by a hydrothermal-calcination method. The removal performance of the Ag/Mn/CeO2 catalyst for HCHO was systematically studied, and its surface chemical properties and microstructure were analyzed. The incorporation of Ag did not change the mesoporous structure of the Mn/CeO2 catalyst but reduced the pore size and specific surface area. The Ag species included metallic Ag as the main component and part of Ag+. The well-dispersed Ag species on the catalyst provided sufficient active sites for the catalytic oxidation of HCHO. The more the Ag active sites, the more the lattice defects and oxygen vacancies generated from the interaction of Ag with Mn/CeO2. Precisely because of this, the Ag/Mn/CeO2 catalyst exhibited high catalytic activity for HCHO at room temperature with a removal efficiency of 96.76% within 22 h, which is 22.91% higher than that of the Mn/CeO2 catalyst. Moreover, the Ag/Mn/CeO2 catalyst showed good cycling stability and the removal efficiency reached 85.77% after five cycles. Therefore, the as-prepared catalyst is an effective and sustainable material that can be used to remove HCHO from actual indoor polluted air. This paper provides ideas for the research and development of efficient catalysts.

Mobile home residence as a risk factor for adverse events among children in a mixed rural-urban community: A case for geospatial analysis

Background:

Given the significant health effects, we assessed geospatial patterns of adverse events (AEs), defined as physical or sexual abuse and accidents or poisonings at home, among children in a mixed rural–urban community.

Methods:

We conducted a population-based cohort study of children (<18 years) living in Olmsted County, Minnesota, to assess geographic patterns of AEs between April 2004 and March 2009 using International Classification of Diseases, Ninth Revision codes. We identified hotspots by calculating the relative difference between observed and expected case densities accounting for population characteristics (; hotspot ≥ 0.33) using kernel density methods. A Bayesian geospatial logistic regression model was used to test for association of subject characteristics (including residential features) with AEs, adjusting for age, sex, and socioeconomic status (SES).

Results:

Of the 30,227 eligible children (<18 years), 974 (3.2%) experienced at least one AE. Of the nine total hotspots identified, five were mobile home communities (MHCs). Among non-Hispanic White children (85% of total children), those living in MHCs had higher AE prevalence compared to those outside MHCs, independent of SES (mean posterior odds ratio: 1.80; 95% credible interval: 1.22–2.54). MHC residency in minority children was not associated with higher prevalence of AEs. Of addresses requiring manual correction, 85.5% belonged to mobile homes.

Conclusions:

MHC residence is a significant unrecognized risk factor for AEs among non-Hispanic, White children in a mixed rural–urban community. Given plausible outreach difficulty due to address discrepancies, MHC residents might be a geographically underserved population for clinical care and research.

Illuminating the dark side of indoor oxidants

The chemistry of oxidants and their precursors (oxidants*) plays a central role in outdoor environments but its importance in indoor air remains poorly understood. Ozone (O3) chemistry is important in some indoor environments and, until recently, ozone was thought to be the dominant oxidant indoors. There is now evidence that formation of the hydroxyl radical by photolysis of nitrous acid (HONO) and formaldehyde (HCHO) may be important indoors. In the past few years, high time-resolution measurements of oxidants* indoors have become more common and the importance of event-based release of oxidants* during activities such as cleaning has been proposed. Here we review the current understanding of oxidants* indoors, including drivers of the formation and loss of oxidants*, levels of oxidants* in indoor environments, and important directions for future research.

Different types of housing and respiratory health outcomes

Evidence has shown that housing conditions may substantially influence the health of residents. Different types of housing have different structures and construction materials, which may affect indoor environment and housing conditions. This study aimed to investigate whether people living in different types of housing have different respiratory health outcomes. The data from the 1999-2006 National Health and Nutrition Examination Survey were used for the analyses. The types of housing included houses, townhouses, apartments, and mobile homes. Respiratory symptoms included wheezing, coughing, sputum, and dyspnea; respiratory diseases included asthma, chronic bronchitis, emphysema, and chronic obstructive pulmonary disease (COPD). Multiple logistic regression was used to calculate odds ratio (OR) and 95% confidence interval (CI) after adjustment for potential confounding factors. A total of 11,785 participants aged 40 years and older were included in the analyses. Compared with those living in single family houses, participants living in mobile homes were more likely to have respiratory conditions, the OR (95% CI) was 1.38 (1.13-1.69) for wheezing, and 1.49 (1.25-1.78) for dyspnea; whereas participants living in apartments were less likely to have respiratory conditions, the OR (95% CI) was 0.58 (0.36-0.91) for chronic bronchitis, and 0.69 (0.49-0.97) for COPD. Compared with living in single family houses, living in mobile home was associated with worse, whereas living in apartments was associated with better, respiratory health outcomes. Further research is needed to better understand the underlying mechanisms and prevent adverse respiratory effects associated with living in mobile homes.

Smoking status, dental visits and receipt of tobacco counseling in dental office among mobile and trailer home adolescents

BACKGROUND

Mobile and trailer home (MTHs) residents are an understudied group. In this study we determined the cigarette smoking status, dental visits in the past 12 months, and receipt of tobacco counseling in adolescents living in MTHs compared to adolescents living in other types of housing.

METHODS

For this secondary data analysis study, we used data of adolescents aged 10 to 19 years (n = 74,890) from the 2012 Florida Youth Tobacco Survey (FYTS). Weighted multiple logistic regression model was conducted to understand the differences between adolescents living in MTHs compared to those living in other types of housing.

RESULTS

Approximately 6 % of the sample reported living in MTHs. The regression model showed that older (p < 0.0001), female (p = 0.0091), and middle school (p < 0.0001) adolescents were more likely, and those who identified as Asians (p = 0.0006), Black/African Americans (p < 0.0001), and Hispanics (p < 0.0001) were less likely to be living in MTHs compared to their counterparts. Current established smokers (p < 0.0001) and non-established smokers (p < 0.0001) were more likely to report living in MTHs compared to non-smokers. Those reporting to have not visited a dental office (p < 0.0001) were more likely to be living in MTHs. Those who visited a dental office but not received any tobacco counseling (p < 0.0001) were less likely to be living in MTHs compared to their counterparts.

CONCLUSIONS

Current cigarette smokers and those not visiting a dental office were more likely to be MTH adolescents. Adolescents reporting to have received tobacco counseling in a dental office were more likely to be living in MTHs.

Human health risks of formaldehyde indoor levels: An issue of concern

Formaldehyde is a carcinogenic substance for humans. Exposure to formaldehyde may also cause eye and respiratory tract irritation, as well as skin sensitization. The main indoor sources of formaldehyde are wood-pressed products, insulation materials, paints, varnishes, household cleaning products and cigarettes, among others. Although this chemical is a well-known indoor pollutant, data on indoor concentrations of formaldehyde are still scarce in some countries. In February 2014, 10 homes in Catalonia, Spain, were randomly selected to collect indoor (bedroom and living room) and outdoor air samples. Ten additional samples were also collected at different workplaces (e.g., offices, shops, classrooms, etc.). Formaldehyde air levels found in homes ranged from 10.7 to 47.7 μg m(-3), from 9.65 to 37.2 μg m(-3), and from 0.96 to 3.37 μg m(-3) in bedrooms, living rooms, and outdoors, respectively. Meanwhile, at workplaces, indoor air levels ranged from 5.86 to 40.4 μg m(-3). These levels are in agreement with data found in the scientific literature. Non-carcinogenic risks were above the threshold limit (HQ > 1), and carcinogenic risks were not acceptable either (>10(-4)). Despite the current study limitations, the results confirm that formaldehyde indoor levels are a matter of health concern, which must be taken into account by policymakers and regulatory bodies.

The effects of an energy efficiency retrofit on indoor air quality

To investigate the impacts of an energy efficiency retrofit, indoor air quality and resident health were evaluated at a low-income senior housing apartment complex in Phoenix, Arizona, before and after a green energy building renovation. Indoor and outdoor air quality sampling was carried out simultaneously with a questionnaire to characterize personal habits and general health of residents. Measured indoor formaldehyde levels before the building retrofit routinely exceeded reference exposure limits, but in the long-term follow-up sampling, indoor formaldehyde decreased for the entire study population by a statistically significant margin. Indoor PM levels were dominated by fine particles and showed a statistically significant decrease in the long-term follow-up sampling within certain resident subpopulations (i.e. residents who report smoking and residents who had lived longer at the apartment complex).

The formaldehyde dilemma

The IARC's 2004 classification of formaldehyde as a human carcinogen has led to intensive discussion on scientific and regulatory levels. In June 2014, the European Union followed and classified formaldehyde as a cause of cancer. This automatically triggers consequences in terms of emission minimization and the health-related assessment of building and consumer products. On the other hand, authorities are demanding and authorizing technologies and products which can release significant quantities of formaldehyde into the atmosphere. In the outdoor environment, this particularly applies to combusting fuels. The formation of formaldehyde through photochemical smog has also been a recognized problem for years. Indoors there are various processes which can contribute to increased formaldehyde concentrations. Overall, legislation faces a dilemma: primary sources are often over-regulated while a lack of consideration of secondary sources negates the regulations' effects.

Identifying an indoor air exposure limit for formaldehyde considering both irritation and cancer hazards

Formaldehyde is a well-studied chemical and effects from inhalation exposures have been extensively characterized in numerous controlled studies with human volunteers, including asthmatics and other sensitive individuals, which provide a rich database on exposure concentrations that can reliably produce the symptoms of sensory irritation. Although individuals can differ in their sensitivity to odor and eye irritation, the majority of authoritative reviews of the formaldehyde literature have concluded that an air concentration of 0.3 ppm will provide protection from eye irritation for virtually everyone. A weight of evidence-based formaldehyde exposure limit of 0.1 ppm (100 ppb) is recommended as an indoor air level for all individuals for odor detection and sensory irritation. It has recently been suggested by the International Agency for Research on Cancer (IARC), the National Toxicology Program (NTP), and the US Environmental Protection Agency (US EPA) that formaldehyde is causally associated with nasopharyngeal cancer (NPC) and leukemia. This has led US EPA to conclude that irritation is not the most sensitive toxic endpoint and that carcinogenicity should dictate how to establish exposure limits for formaldehyde. In this review, a number of lines of reasoning and substantial scientific evidence are described and discussed, which leads to a conclusion that neither point of contact nor systemic effects of any type, including NPC or leukemia, are causally associated with exposure to formaldehyde. This conclusion supports the view that the equivocal epidemiology studies that suggest otherwise are almost certainly flawed by identified or yet to be unidentified confounding variables. Thus, this assessment concludes that a formaldehyde indoor air limit of 0.1 ppm should protect even particularly susceptible individuals from both irritation effects and any potential cancer hazard.