Inactivation of dust mites, dust mite allergen, and mold from carpet

High-Resolution Mass Spectrometry Screening of Quaternary Ammonium Compounds (QACs) in Dust from Homes and Various Microenvironments in South China

Despite their ubiquitous use, information regarding the presence of quaternary ammonium compounds (QACs) in various microenvironments remains scarce and only a small subset of QACs has been monitored using targeted chemical analysis. In this study, a total of 111 dust samples were collected from homes and various public settings in South China during the COVID-19 pandemic and were analyzed for traditional and emerging QACs using high-resolution mass spectrometry. The total traditional QAC concentrations in residential dust (∑traditional QAC, sum of 18 traditional QACs) ranged from 13.8 to 150 μg/g with a median concentration of 42.2 μg/g. Twenty-eight emerging QACs were identified in these samples, and the composition of ∑emerging QAC (sum of emerging QACs) to ∑QAC (sum of traditional and emerging QACs) ranged from 19 to 42% across various microenvironments, indicating the widespread existence of emerging QACs in indoor environments. Additionally, dust samples from cinemas exhibited higher ∑QAC concentrations compared to homes (medians 65.9 μg/g vs 58.3 μg/g, respectively), indicating heavier emission sources of QACs in these places. Interestingly, significantly higher ∑QAC concentrations were observed in dust from the rooms with carpets than those without (medians 65.6 μg/g vs 32.6 μg/g, p < 0.05, respectively). Overall, this study sheds light on the ubiquitous occurrence of QACs in indoor environments in South China.

Human ectoparasitosis by mites of the genus Pyemotes Amerling 1861 (Acarina: Pyemotidae)

The mites of the family Pyemotidae Berlese (1897) are a large family of ectoparasitoids arthropods, known as pathogen for humans since the 18^th century and responsible for the so-called "straw itch" or "grain itch" in granary and dock workers. The identified species of the genus Pyemotes are divided into two groups: the scolyti group (P. scolyti, P. parviscolyti and P. dimorphus) and the ventricosus group (P. tritici and P. ventricosus). The first group is characterized by nonvenomous mites usually parasitizing bark beetles; the ventricosus group includes species associated with a large number of hosts (Coleoptera, Lepidoptera, Hymenoptera, Diptera and Rhynchota), parasitizing all host stages, often highly poisonous and responsible for itchy skin lesions for humans. Several species of Pyemotes mites can be pathogenic to humans, especially in spring and summer and in indoor environments, where worm-eaten wood or infested foodstuffs are present. The most frequent clinical feature is the "strophulus," characterized by small erythematous, edematous, and papular lesions centered by a tiny vescicle evolving into a small erosion covered by crust, or by a central hemorrhagic punctum. Other less frequently observed clinical features are urticaria-like lesions, erythematous excoriated papular and pustular lesions, and rarely scabies-like eruptions. The parasitological diagnosis together with the environmental disinfestation and removing of each substrate infested by insects parasitized by Pyemotidae is mandatory to definitely solve Pyemotes dermatitis.

Simultaneous assessment of organophosphate flame retardants, plasticizers, trace metals, and house dust mite allergens in settled house dust

Settled house dust (SHD) is a reservoir for various contaminants, including endocrine-disrupting chemicals (EDCs), trace metals, and house dust mite allergens. This study aimed to characterize various chemical and biological contaminants in SHD and identify determinants governing the indoor contaminants. In total, 106 SHD samples were collected from 106 houses in Seoul and Gyeonggi Province, Korea, in 2021. Bedding dust samples were collected from 30 of these 106 houses. All participants completed a questionnaire comprised of housing and lifestyle-related factors. The samples were analyzed for 18 organophosphate flame retardants (OPFRs), 16 phthalates, five alternative plasticizers (APs), seven trace metals, and two house dust mite allergens (Dermatophagoides farinae type 1 [Der f1] and Dermatophagoides pteronyssinus type 1 [Der p1]). A multiple regression analysis was conducted to identify the determinants governing the concentrations and profiles of various contaminants. OPFRs, phthalates, APs, and trace metals were detected in all SHD samples, indicating ubiquitous contamination in indoor environments. Among the three EDC groups, APs were detected at the highest concentrations (geometric mean [GM] (geometric standard deviation, [GSD]): 1452 (1.6) μg/g in total), followed by phthalates (GM (GSD): 676 (1.4) μg/g in total) and OPFRs (GM (GSD): 10 (1.4) μg/g in total). Der f1 was detected in all bedding dust samples with significantly higher levels than Der p1 (GM (GSD): 0.1 (1.8) μg/g vs. 1.4 × 10^-3 (2.3) μg/g). The concentrations of OPFRs, plasticizers, and trace metals in SHD were significantly associated with the type and number of electronic appliances and combustion activities. Der f1 was significantly associated with the number of occupants and water penetration. Ventilation, vacuum cleaning, and wet cleaning or dry mopping significantly reduced the levels of most contaminants in SHD. As residents are persistently exposed to a wide array of pollutants, comprehensive and adequate measures are required to prevent potential exposures.

Update on indoor allergens and their impact on pediatric asthma

OBJECTIVE

In recent decades, many indoor allergens have been identified, including dust mite, cat, dog, mouse, cockroach, and indoor molds, which have important health effects particularly in sensitized individuals with asthma. This review aims to update our understanding regarding the extent of these exposures in the indoor environment, review strategies for reducing their levels in the environment, and highlight innovative recent trials targeting these exposures and their impact on pediatric asthma morbidity.

DATA SOURCES

Recent practice parameter updates on indoor allergen exposures, seminal studies, and recent peer-reviewed journal articles are referenced.

STUDY SELECTIONS

This review cites recent cohort studies of well-characterized pediatric patients with asthma and innovative randomized controlled trials evaluating exposure to environmental allergens, interventions to limit these exposures, and their outcomes.

RESULTS

Links between indoor aeroallergen exposures and health outcomes have been well established. However, only some allergen reduction interventions have been successful in improving health outcomes.

CONCLUSION

There are many complicating factors involved in allergic exposures and health outcomes. The interplay between patient genetic factors, indoor allergic triggers, airborne irritants and pollutants, and microbial exposures complicates the study of indoor allergen exposures and their impact on asthma morbidity.

Ten questions concerning the implications of carpet on indoor chemistry and microbiology

Carpet and rugs currently represent about half of the United States flooring market and offer many benefits as a flooring type. How carpets influence our exposure to both microorganisms and chemicals in indoor environments has important health implications but is not well understood. The goal of this manuscript is to consolidate what is known about how carpet impacts indoor chemistry and microbiology, as well as to identify the important research gaps that remain. After describing the current use of carpet indoors, questions focus on five specific areas: 1) indoor chemistry, 2) indoor microbiology, 3) resuspension and exposure, 4) current practices and future needs, and 5) sustainability. Overall, it is clear that carpet can influence our exposures to particles and volatile compounds in the indoor environment by acting as a direct source, as a reservoir of environmental contaminants, and as a surface supporting chemical and biological transformations. However, the health implications of these processes are not well known, nor how cleaning practices could be optimized to minimize potential negative impacts. Current standards and recommendations focus largely on carpets as a primary source of chemicals and on limiting moisture that would support microbial growth. Future research should consider enhancing knowledge related to the impact of carpet in the indoor environment and how we might improve the design and maintenance of this common material to reduce our exposure to harmful contaminants while retaining the benefits to consumers.