Microfiber-loaded bacterial community in indoor fallout and air-conditioner filter dust

Physicochemical characteristics of airborne microplastics of a typical coastal city in the Yangtze River Delta Region, China

Airborne microplastics (MPs) are important pollutants that have been present in the environment for many years and are characterized by their universality, persistence, and potential toxicity. This study investigated the effects of terrestrial and marine transport of MPs in the atmosphere of a coastal city and compared the difference between daytime and nighttime. Laser direct infrared imaging (LDIR) and polarized light microscopy were used to characterize the physical and chemical properties of MPs, including number concentration, chemical types, shape, and size. Backward trajectories were used to distinguish the air masses from marine and terrestrial transport. Twenty chemical types were detected by LDIR, with rubber (16.7%) and phenol-formaldehyde resin (PFR; 14.8%) being major components. Three main morphological types of MPs were identified, and fragments (78.1%) are the dominant type. MPs in the atmosphere were concentrated in the small particle size segment (20-50 µm). The concentration of MPs in the air mass from marine transport was 14.7 items/m3 - lower than that from terrestrial transport (32.0 items/m3). The number concentration of airborne MPs was negatively correlated with relative humidity. MPs from terrestrial transport were mainly rubber (20.2%), while those from marine transport were mainly PFR (18%). MPs in the marine transport air mass were more aged and had a lower number concentration than those in the terrestrial transport air mass. The number concentration of airborne MPs is higher during the day than at night. These findings could contribute to the development of targeted control measures and methods to reduce MP pollution.

Microplastics in indoor air from Birmingham, UK: Implications for inhalation exposure

Microplastics (MPs) are a group of emerging contaminants that attracted increasing scientific and societal attention over the past decade. So far, most studies on MPs focus on characterizing their occurrence, fate, and impact in the aquatic environment. In contrast, very little is known about the magnitude, patterns, and associated risks of human exposure to MPs, particularly indoors, despite people spending most of their time indoors. This paper provides the first study hitherto of MPs in indoor air via both active and passive sampling from 30 homes and 30 workplaces in Birmingham, UK. The average concentration of MPs in the active air samples was 15.6 ± 5.4 MP/m3 in homes and 13.1 ± 6.5 MP/m3 in workplaces. For atmospheric deposition samples (passive sampling), the average MPs concentrations were 3735 ± 1343 MP/m2/day in homes and 3177 ± 1860 MP/m2/day in workplaces. Mean concentrations of MPs in UK homes were significantly higher (P<0.05) than those in workplaces for both active and passive air samples. This was mainly driven by carpeted floors in all the studied homes, while 13 of the sampled workplaces were uncarpeted. MPs concentrations in atmospheric deposition (passive) samples were significantly higher (P < 0.05) than airborne (active) MPs samples in the studied microenvironments. Nonetheless, a strong correlation (P < 0.01) was observed between the concentrations of MPs measured by active and passive sampling, indicating common sources of MPs to both active and passive samples collected from the same microenvironments. In terms of morphology, fibres were the dominant shape of MPs, followed by fragments, constituting together ≥90% of the identified MPs in all samples, with the remaining minor percent made up by foams. Airborne MPs were dominated by particles in the size range (10-25 μm), and the particles abundance decreased with increasing particle size. MPs in atmospheric fallout particles, were dominated by larger particles (50-100 μm) with lower contribution from smaller particles (10-25 μm) compared to airborne particles. Nonetheless, combined with the predominance of fibres, this raises concern over the risk from inhalation exposure because MPs fibres in the detected size ranges were observed to penetrate into human lung tissue. PET and PVC were the most abundant polymer types in the studied samples followed by PP and PE. The average daily inhalation exposure of UK adults and toddlers was estimated at 3.0 and 6.3 MP/kg body weight/day, respectively. The higher inhalation exposure of UK toddlers raises concern due to their incompletely developed immune and nervous systems.

Bacterial contamination in the different parts of household air conditioners: a comprehensive evaluation from Chengdu, Southwest China

Introduction

Air flow driven by air-conditioner has a significant impact on the indoor environment, however, the bacterial contamination conditions in the different parts of air-conditioners have not been fully elucidated.

Methods

In this study, we assessed the bacterial pollution in the four parts, including air outlet, filter net, cooling fin and water sink, of ten household air-conditioners quantitatively and qualitatively from Chengdu, southwestern China.

Results

The microbial cultivation results showed the large total bacterial counts of 5042.0, 9127.6, 6595.1, and 12296.2 CFU/cm2 in air outlet, filter net, cooling fin, and water sink. Furthermore, the sequencing data showed that these four parts displayed different bacterial characteristics. At the level of genus, Caproiciproducens and Acidipropionibacterium were predominant in air outlet. Bacillus, Acinetobacter, Paracoccus, and Corynebacterium were detected as the characteristic bacteria in filter net. For cooling fin, Rhodococcus, Achromobacter, and Nocardioides were the dominant bacteria. The genera of Methylobacterium-Methylorubrum, Brevibacterium, Stenotrophomonas, and Psychrobacter were identified as the bioindicators in water sink. The bioinformatic analysis on the sequencing data illustrated that the bacteria from air-conditioners were associated with metabolic disturbance.

Discussion

This study reveals the distinct bacterial compositions in the different parts of air-conditioner, and provides new clues for the non-negligible bacterial pollution in this common appliance from Chinese households.

Microplastics suspended in dust from different indoor environments in Barranquilla, Colombia: Predominant microparticles?

Considering that microplastics (MPs) are classified as ubiquitous pollutants, that air quality affects human health, and that people remain indoors most of the time, the need has arisen to evaluate the exposure to MPs within the suspended dust in indoor environments. With this objective, the present study carried out passive sampling to analyze the precipitation of microparticles in some indoor residential environments (2 apartments) and workplaces (an office, a pastry shop, a gift shop, and a paint shop) in Barranquilla, Colombia. The quantification and physical characterization of microparticles were carried out under a stereomicroscope, and the chemical characterization was carried out by infrared microspectroscopy (μFTIR). The highest average concentration of MPs in the apartments was found in the air-conditioned rooms (1.1 × 104 MP/m2/day), and concerning the workplaces, the gift shop and the paint shop were the spaces with a higher proportion of MPs (6.0-6.1 × 103 MP/m2/day), with polyesters being the main synthetic polymers, but being semi-synthetic particles the predominant among the samples. Regarding its morphology, fibers were the most abundant shape (>90%), grouping mainly in the 1000-5000 μm range, while the few fragments found were mostly grouped below 50 μm. Exposure by inhalation of MPs in adults was estimated between 1.7 × 102-1.6 × 103 MP/kg/day, while by ingestion it ranged between 2.7 × 102-2.4 × 103 MPs/kg/day. On the other hand, within our research, a significant presence of non-plastic microparticles was found, which reached up to 69% in analyzed samples, corresponding mainly to cotton and cellulose, so we suggest that these should also be included in future studies that aim to estimate potential health implications from exposure to suspended micropollutants.

Beyond the cradle - Amidst microplastics and the ongoing peril during pregnancy and neonatal stages: A holistic review

Advancements in research concerning the occurrence of microplastics (MPs) in human blood, sputum, urine, and breast milk samples have piqued the interest of the scientific community, prompting further investigation. MPs present in the placenta, amniotic fluid, and meconium raise concerns about interference with embryonic development, leading to preeclampsia, stillbirth, preterm birth, and spontaneous abortion. The challenges posed by MPs extend beyond pregnancy, affecting the digestive, reproductive, circulatory, immune, and central nervous systems. This has spurred scientists to examine the origins of MPs in distinct environmental layers, including air, water, and soil. These risks continue after birth, as neonates are continuously exposed to MPs through everyday items such as breast milk, cow milk and infant milk powder, as well as plastic-based products like feeding bottles and breast milk storage bags. It is the need of the hour to strike a balance amidst lifestyle changes, alternative choices to traditional plastic products, raising awareness about plastic-related health risks, and fostering collaboration between the scientific community and policymakers. This review aims to provide fresh insights into potential sources of MP pollution, with a specific focus on pregnancy and neonates. It is the first compilation of its kind so far that includes critical studies on recently reported discoveries.

Unveiling the overlooked microbial niches thriving on building exteriors

Rapid urbanization in the Asia-Pacific region is expected to place two-thirds of its population in concrete-dominated urban landscapes by 2050. While diverse architectural facades define the unique appearance of these urban systems. There remains a significant gap in our understanding of the composition, assembly, and ecological potential of microbial communities on building exteriors. Here, we examined bacterial and protistan communities on building surfaces along an urbanization gradient (urban, suburban and rural regions), investigating their spatial patterns and the driving factors behind their presence. A total of 55 bacterial and protist phyla were identified. The bacterial community was predominantly composed of Proteobacteria (33.7% to 67.5%). The protistan community exhibited a prevalence of Opisthokonta and Archaeplastida (17.5% to 82.1% and 1.8% to 61.2%, respectively). The composition and functionality of bacterial communities exhibited spatial patterns correlated with urbanization. In urban buildings, factors such as facade type, light exposure, and building height had comparatively less impact on bacterial composition compared to suburban and rural areas. The highest bacterial diversity and lowest Weighted Average Community Identity (WACI) were observed on suburban buildings, followed by rural buildings. In contrast, protists did not show spatial distribution characteristics related to facade type, light exposure, building height and urbanization level. The distinct spatial patterns of protists were primarily shaped by community diffusion and the bottom-up regulation exerted by bacterial communities. Together, our findings suggest that building exteriors serve as attachment points for local microbial metacommunities, offering unique habitats where bacteria and protists exhibit independent adaptive strategies closely tied to the overall ecological potential of the community.