Office Indoor PM and BC Level in Lithuania: The Role of a Long-Range Smoke Transport Event

While the impacts of climate change on wildfires and resulting air pollution levels have been observed, little is known about how indoor air filtering systems are performing under intensive smoke conditions. For this aim, particle number size distribution and concentration in a size range 0.5–18 μm and equivalent black carbon (eBC) mass concentration were measured in a modern office with a mechanical ventilation system. Measurements took place from 30 September to 6 October 2020 in the Center for Physical Sciences and Technology (FTMC) campus located in the urban background environment in Lithuania. During the measurement campaign, an intensive pollution episode, related to long-range transport wildfire smoke, was observed. The results indicated that the smoke event increased both indoor and outdoor eBC mass concentrations twice. Filters were non-selective for different eBC sources (biomass burning versus traffic) or chemical composition of carbonaceous aerosol particles (eBC versus brown carbon (BrC)). Air filtering efficiency was found to be highly dependent on particle size. During the smoke event the highest particle number concentration was observed at 2.1 μm and 1.0 μm size particles in outdoor and indoor air, respectively. Differences of indoor to outdoor ratio between event and non-event days were not significant. Because of lower removal rate for small particles, eBC had higher contribution to total PM2.5 mass concentration in indoor air than in outdoor air. The results gained are crucial for decision-making bodies in order to implement higher-quality air-filtering systems in office buildings and, as a result, minimize potential health impacts. © 2021 by the authors

Potential for Inhalation Exposure to Engineered Nanoparticles from Nanotechnology-Based Cosmetic Powders

Background: The market of nanotechnology-based consumer products is rapidly expanding, and the lack of scientific evidence describing the accompanying exposure and health risks stalls the discussion regarding its guidance and regulation

Efficacy of Filter Improvements for Transit Vehicles to Combat the Spread of COVID-19 and Other Respiratory Infections

69A3551847102The COVID-19 pandemic has been a worldwide issue that transit agencies are still struggling to find cost-efficient solutions to. Upgrading the filters used on trains and buses to reduce the airborne transmission of the SARS-CoV-2 virus as well as other infectious viruses, such as influenza, may be an effective, cost-efficient way of containing the very small, hard-to-filter droplet and aerosol particles that these viruses may travel within. One way to improve transit vehicle air quality and safety is to upgrade the current MERV-rated filters to higher-rated ones such as a MERV 13 filter. This study will look at quantifying the upgraded filters\u2019 performance, focusing on their efficacy over time and comparing them to a MERV 8 filter. Filter performance was investigated using sodium chloride (NaCl) particles and Arizona Road Dust (ARD) particles to determine the filter collection efficiency. A Grimm MiniWras and Aerodynamic Particle Sizer was used to compare the number concentrations (#/L) of particles upstream and downstream of the filter. The filter testing data confirm that MERV-13 filters have better filtration efficiency compared to MERV-8 filters but the filter performance varies depending on the age of the filter (i.e., its loading), particle type, and particle properties (charged vs. neutralized)

Investigation of Sources, Diversity, and Variability of Bacterial Aerosols in Athens, Greece: A Pilot Study

We characterized the composition, diversity, and potential bacterial aerosol sources in Athens’ urban air by DNA barcoding (analysis of 16S rRNA genes) during three seasons in 2019. Air samples were collected using the recently developed Rutgers Electrostatic Passive Sampler (REPS). It is the first field application of REPS to study bacterial aerosol diversity. REPS samplers captured a sufficient amount of biological material to demonstrate the diversity of airborne bacteria and their variability over time. Overall, in the air of Athens, we detected 793 operational taxonomic units (OTUs), which were fully classified into the six distinct taxonomic categories (Phylum, Class, Order, etc.). These OTUs belonged to Phyla Actinobacteria, Firmicutes, Proteobacteria, Bacteroidetes, Cyanobacteria, and Fusobacteria. We found a complex community of bacterial aerosols with several opportunistic or potential pathogens in Athens’ urban air. Referring to the available literature, we discuss the likely sources of observed airborne bacteria, including soil, plants, animals, and humans. Our results on bacterial diversity are comparable to earlier studies, even though the sampling sites are different or geographically distant. However, the exact functional and ecological role of bioaerosols and, even more importantly, their impact on public health and the ecosystem requires further air monitoring and analysis