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Understanding the relationship between consumer product use and risk of adverse health outcomes facilitates appropriate risk management and product stewardship. A preferred method for estimating the systemic and respiratory tract exposure and dose tailored to cleaning products use has been proposed, refining previously issued exposure guidance. Consistent with other exposure and risk-assessment frameworks, it is dependent upon high-quality exposure determinant data that also serve as model inputs. However, as publicly available exposure determinant data are scarce, the risk assessor is left with the option of estimating determinants such as the generation rate or employing empirical methods to estimate them. When the exposure scenario involves a chemical mixture, estimating the generation rate may not be feasible. We present an approach for estimating the time-varying generation rate of an aqueous acetic acid mixture representative of the base formulation for many consumer and DIY cleaning products that was previously assessed in a screening-level assessment. The approach involved measuring the evaporation rate for a reasonable worst-case scenario under controlled conditions. Knowing the mass applied, a time-varying generation rate was estimated. To evaluate its portability, a field study was conducted in a home where measurements were collected in an all-purpose room with the exterior door open (Room 1) and closed (Room 2), and a bathroom (Room 3) using a portable Fourier Transform Infrared (FTIR) spectrophotometer. Acetic acid concentrations were modeled using two common indoor air models, the Well Mixed Room model. Measured and modeled acetic acid concentrations were compared, with the WMR 95% confidence intervals encompassing measured concentrations for all three rooms, supporting the utility of the approach used and portability of the generation rate derived from it.

Little is known about the etiology of hepatoblastoma. We aimed to confirm the results of a previous study evaluating the association between parental occupational exposures and hepatoblastoma. In our case–control study, we identified cases ( n =383) from the Children’s Oncology Group and controls from birth certificates ( n =387), which were frequency matched to cases on year and region of birth, sex, and birth weight. Occupational exposure in the year before and during the index pregnancy was collected through maternal interview and analyzed using unconditional logistic regression. The odds of both paternal and maternal “Likely” exposure to paints was elevated among cases compared with controls (paternal odds ratio (OR): 1.71, 95% confidence interval (CI): 1.04, 2.81; maternal OR: 3.29, 95% CI: 0.32, 33.78) after adjustment for matching factors and the confounding factors of maternal race (maternal only) and household income. In addition, paternal exposure to other chemicals was also elevated when adjusting for matching factors only (OR: 1.53, 95% CI: 1.02, 2.30). The results of our study provide further evidence of an association between parental occupation and hepatoblastoma. These results warrant further investigation of the etiologically relevant timing of occupational exposure to fumes and chemicals related to hepatoblastoma.

IntroductionWe examined the association between cumulative silica exposures in taconite mining and non-malignant respiratory disease (NMRD) using a comprehensive assessment of current and historical exposure measurements in a cross-sectional study of Minnesota taconite mining workers. We also explored the impact of exposure measurement methods by comparing estimated exposure risk from two different exposure measurement modeling approaches.MethodsMiners were screened with an occupational and medical history questionnaire, spirometry testing and chest x-rays per ILO guidelines. Current and historical occupational exposure assessments were obtained, the former measuring about 679 personal samples over the period of the study for respirable dusts, including silica, in 28 major job functions. Cumulative silica exposure ((mg/m3) × years) was estimated as a cumulative product of time worked and year-specific silica job exposure concentrations. Chest x-ray abnormalities were based on B-reader agreement with a third B-reader for arbitration. Forced vital capacity (FVC) less than lower limits of normal for age, height, race and gender was used to determine spirometric restrictive ventilatory defect (RVD). Prevalence ratios (PR) of exposure-outcome associations, with 95% confidence intervals (CI), were estimated using multivariate Poisson regression.ResultsCumulative silica exposure was associated with RVD prevalence (PR = 1.41, 95% CI = 1.09–1.81) and prevalence of parenchymal abnormalities on chest x-ray (PR = 1.30, 95% CI = 1.00–1.69) using exposure estimates based primarily on current study measurements, and assuming unchanged historical exposure trend. Conversely, when exposures were defined incorporating available actual historical values, no associations were observed between silica exposure and either RVD (PR = 0.76, 95% CI = 0.41–1.40) or parenchymal (PR = 0.87, 95% CI = 0.45–1.70) outcomes.ConclusionsThis study demonstrated that the estimated association between silica dust exposure and lung disease is highly sensitive to the approach used to estimate cumulative exposure. Cumulative values based on conservative estimates of past exposure, modeled from recently measured respirable silica, showed an association with restriction RVD on spirometry. Silica exposure was also significantly associated with increased parenchymal findings on chest x-ray using this approach. Conversely, these findings were absent when actual available historical data was used to estimate cumulative silica exposure. These differences highlight the challenges with estimating occupational dust exposure, the potential impact on calculated exposure risk and the need for long term quality exposure data gathering in industries prone to risk from inhaled respirable dusts.

We measured volatile organic compound (VOC) exposures in multiple locations for a diverse population of children who attended two inner-city schools in Minneapolis, Minnesota. Fifteen common VOCs were measured at four locations: outdoors (O), indoors at school (S), indoors at home (H), and in personal samples (P). Concentrations of most VOCs followed the general pattern O ≈ S < P ≤ H across the measured microenvironments. The S and O environments had the smallest and H the largest influence on personal exposure to most compounds. A time-weighted model of P exposure using all measured microenvironments and time-activity data provided little additional explanatory power beyond that provided by using the H measurement alone. Although H and P concentrations of most VOCs measured in this study were similar to or lower than levels measured in recent personal monitoring studies of adults and children in the United States, p-dichlorobenzene was the notable exception to this pattern, with upper-bound exposures more than 100 times greater than those found in other studies of children. Median and upper-bound H and P exposures were well above health benchmarks for several compounds, so outdoor measurements likely underestimate long-term health risks from children's exposure to these compounds.

Allergens and other pollutants in house dust are collected using a variety of dust samplers that are assumed to operate similarly. This factorial design study compared sampler performance under controlled environmental conditions. House dust with known particle sizes (212–90, 90–45, and <45  μ m) and allergen concentrations were sampled from new carpet squares with varying denier, pile height and pile densities. Dust mass and allergen recovery for total dust mites (Der p 1 and Der f 1), cat (Fel d 1) and cockroach allergen (Bla g 1) were assessed using the Eureka Mighty Mite (EURK), the High Volume Small Surface Sampler (HVS), or the American Industrial Hygiene Association (AIHA) method. Allergen concentrations were quantified using enzyme-linked immunosorbent assays, and dust mass results were corrected for carpet fiber shedding. Samplers were compared by exploring mass collection efficiency (CE=fiber corrected dust mass/applied dust mass) and concentration ratio (CR=allergen concentration in collected sample/allergen concentration in test dust). Test dust allergen concentrations varied by particle size fraction due to varying laboratory performance over time. The EURK and HVS samplers had CEs of 41–63% in the small and medium particle size fractions, and collected less than 20% of the available dust from the large size fraction. The AIHA CE ranged from 10% to 17% in the medium and small particle size fractions, but collected little dust in the largest particle size fraction. The AIHA and HVS samplers were more likely to acquire more representative and less variable allergen CRs compared with the EURK method. Health studies that use allergen concentration as an exposure metric need to consider the implications of sampler performance when interpreting links to health outcomes and development of health-based standards for allergens in house dust.

ObjectivesAn excess of mesothelioma has been previously observed in iron ore miners in Northeastern Minnesota. This study explored the potential association between mesothelioma and elongate mineral particle (EMP) exposures in the Minnesota taconite mining industry, examining both regulated and non-regulated EMP dimensions.MethodsA nested case–control study design within the Mineral Resources Health Assessment Programme cohort analysed 104 mesothelioma cases and 410 controls. Cumulative EMP exposures were assessed across various dimensional definitions, including regulated (National Institute for Occupational Safety and Health, NIOSH) and non-regulated EMPs. Conditional logistic regression models were applied to estimate mesothelioma risk linked to employment duration and cumulative EMP exposure while adjusting for potential confounding variables.ResultsConsistent with earlier assessments, mesothelioma was associated with the number of years employed in the taconite industry (rate ratio (RR) 1.02, 95% CI 1.00 to 1.05) and cumulative NIOSH EMP exposure ((EMP/cc)×years) in taconite mining and processing (RR 1.20, 95% CI 0.99 to 1.46). Positive associations were also observed with mesothelioma and cumulative exposure to non-regulated EMPs.ConclusionsThis study supported the main conclusions in the previous study that the data were consistent with an association between mesothelioma and employment duration and with NIOSH EMP exposure in taconite mining and processing. However, the 95% CI indicates the data are also compatible with a null effect. Given the limitations we cite in the manuscript, additional study is needed to clarify the effect. Additionally, this study found possible evidence of a positive association between mesothelioma and cumulative exposure to Chatfield EMP, Suzuki EMP and Cleavage Fragments in the Minnesota taconite worker population.

Allergens in house dust are risk factors for asthma causation and exacerbation, and asthma interventions often focus on exposure reduction using methods that may not be sustainable over time in low-income communities. A randomized controlled trial with up to six home visits was used to evaluate the effectiveness of two interventions focused on reducing dust loading and allergen concentrations in 47 low-income inner-city households in Minneapolis, MN. The interventions, which included education and relatively inexpensive cleaning procedures, were developed using a community-based participatory consultation process with focus groups held in English, Somali, and Spanish to incorporate community feedback from participants into protocols and study design decisions. Change in levels of cat, cockroach, dust mite, and culturable fungi as well as overall dust loading were evaluated by measuring the difference in concentrations before and after the cleaning intervention, and mixed models were used to assess the effect of education and cleaning on baseline allergen levels during the final three home visits. The cleaning intervention significantly lowered dust loading in all households and culturable fungi levels in single family homes, reduced cat allergen concentrations in homes with cats, but had no significant effect on cockroach allergen levels. The cleaning intervention also modestly decreased the frequency of observed allergen concentrations above suggested health benchmarks for cat, cockroach, and fungi. The cleaning and education interventions had similar effects on baseline allergen levels measured during subsequent home visits; both interventions significantly reduced baseline levels of cat and fungal allergens observed in pre-cleaning samples, but had no significant effect on cockroach allergen levels. Overall, the cleaning intervention modestly reduced potential exposure to risk factors associated with asthma mortality and morbidity in a way that can be implemented by most homeowners or renters, independent of education, income, or the ability to speak English.

ObjectivesBrick kiln workers in Nepal are a neglected population who are exposed to high respirable silica concentrations, and few use interventions to reduce exposure. We aimed to characterise the prevalence of respiratory personal protective equipment (PPE) use, understand knowledge and attitudes towards kiln dust and respiratory PPE and identify factors associated with respiratory PPE use.MethodsWe conducted a cross-sectional study in Bhaktapur, Nepal. We used simple random selection to identify 10 out of 64 total kilns and stratified random sampling of 30 households to enrol workers aged ≥14 years within selected kilns. Field workers surveyed participants using structured questionnaires. Our primary outcome was to characterise the prevalence of current respiratory PPE use and secondary outcomes were summaries of knowledge, attitudes and practice of PPE use.ResultsWe surveyed 83 workers (mean age 30.8 years, 77.1% male). Of these, 28.9% reported current respiratory PPE use at work, 3.6% heard of silicosis prior to the survey and 24.1% correctly identified the best respiratory PPE (N95, compared with surgical masks and barrier face coverings) for reducing dust exposure. Respiratory PPE users had higher income (mean monthly household income US$206 vs US$145; p=0.04) and education levels (25% vs 5.1% completed more than primary school; p=0.02) compared with non-users.ConclusionsRespiratory PPE use was low. Workers had poor knowledge of kiln dust health effects and proper respiratory PPE. We highlight important barriers to PPE use, particularly knowledge gaps, which can guide future investigations to reduce the silicosis burden among brick kiln workers.

In many occupational hygiene settings, the demand for more accurate, more precise results is at odds with limited resources. To combat this, practitioners have begun using Bayesian methods to incorporate prior information into their statistical models in order to obtain more refined inference from their data. This is not without risk, however, as incorporating prior information that disagrees with the information contained in data can lead to spurious conclusions, particularly if the prior is too informative. In this paper, we propose a method for constructing informative prior distributions for normal and lognormal data that are intuitive to specify and robust to bias. To demonstrate the use of these priors, we walk practitioners through a step-by-step implementation of our priors using an illustrative example. We then conclude with recommendations for general use.

In many occupational hygiene settings, the demand for more accurate, more precise results is at odds with limited resources. To combat this, practitioners have begun using Bayesian methods to incorporate prior information into their statistical models in order to obtain more refined inference from their data. This is not without risk, however, as incorporating prior information that disagrees with the information contained in data can lead to spurious conclusions, particularly if the prior is too informative. In this paper, we propose a method for constructing informative prior distributions for normal and lognormal data that are intuitive to specify and robust to bias. To demonstrate the use of these priors, we walk practitioners through a step-by-step implementation of our priors using an illustrative example. We then conclude with recommendations for general use.