Indoor Air Quality Intervention in Schools; Effectiveness of a Portable HEPA Filter Deployment in Five Schools Impacted by Roadway and Aircraft Pollution Sources

The Healthy Air, Healthy Schools Study was established in January 2020 to better understand the impact of ultrafine particles (UFP) on indoor air quality in communities surrounding Seattle-Tacoma (Sea-Tac) International Airport. The study team took multipollutant measurements indoor and outdoor air pollution at five participating school locations to infiltration indoors. The schools participating in this project were located within a 7-mile radius of Sea-Tac Airport and within 0.5 miles of an active flight path. Based on experimental measures in an unoccupied classroom, infiltration rates of a) Ultrafine particles of aircraft origin b) Ultrafine particles of traffic origin and c) Wildfire smoke or other outdoor pollutants were characterized before and after the introduction of a classroom based portable HEPA filter intervention. The portable HEPA cleaners were an effective short-term intervention to improve the air quality in classroom environments, reducing the ultrafine particles to approximately 1/10th of that measured outside. Before the HEPA filter deployment, approximately one-half of all outdoor UFPs were measured indoors. This study is unique in focusing on UFP in school settings and demonstrating through multivariate methods that the UFP measured in the classroom space is primarily of outdoor origin. Although existing research suggests that improvements to indoor air quality in homes can significantly improve asthma outcomes, further research is necessary to establish the benefit to student health and academic performance of improved air quality in schools.

Strategies for Reducing Ruminant Methane Emissions

The paper studies the effect of additional administration of ultrafine particles on the cattle rumen microbiome composition. The in vitro method was used using the ANKOM Daisy II incubator according to a specialized method. Microflora analysis was performed using MiSeq (Illumina, USA) by a new generation sequencing method with a MiSeq reagent kit. After a detailed analysis of the structure and composition of the microbial community in the contents of the rumen sampled for different diets, it was found that no significant differences were observed in the bacterial communities, with the exception of a slight shift in the Bacteroidetes/Firmicutes ratio. However, we observed numerical differences in the abundance of some representatives, namely, with additional inclusion of Fe and Cr2O3, decrease in the abundance of the methane-forming species Methanobrevibacter, Methanobacterium, Methanosphaera, and Methnaomicrobium was noted regarding the control.

Effective use of innovative technologies in mixed sowing of annual crops

It is impossible to organize proper feeding of farm animals without a detailed study of the composition of the nutritional content of feed. Legume-grass mixtures occupy one of main places in solving the problem of high-quality feed production. Since mixed crops of legumes and cereals retain high fodder quality of green mass due to high protein content in legumes. To meet the need for a high-quality feed base, it is necessary to look for ways to increase the yield of fodder crops. The use of innovative technologies is one of the components of modern crop production. The aim of the study was to study the methods of seed treatment in conjunction with the technology of mixed crops; it allows obtaining a green mass with the desired productive properties. Thus, the article presents the materials of a field study on the development of a highly productive green feed. The results of the study of combined and mixed crops on the nutritional value and productivity of annual forages of peas, millet, and barley using pre-sowing seed treatment with ultrafine particles of SiO2; MoO2; Fe3O4 and growth regulators AgroVerm and RibavExtra were obtained. As a result of the experiment, it was shown that the use of pre-sowing treatment of seeds with ultradispersed SiO2 particles in combined crops showed the maximum leaf surface area of 85.5 thousand m2/ha. By the time of harvesting, the safety of plants on variants with the use of SiO2; Fe3O4; MoO2 was 88.4%; 87.5%; 86.5% respectively. According to the collection of digestible protein, variant with the use of ultrafine particles SiO2 was 20% in both sowing methods. Low protein content was 16.1%; 16.4% in the control variants respectively. According to the content of feed units in 1 kg of dry matter, SiO2 variants prevail with 0.91. Thus, the research is the basis for possible studying of combined and mixed crops with the use of pre-sowing seed treatment with ultrafine particles. It allows obtaining high-quality feed.

Spatio-Temporal Modeling of Small-Scale Ultrafine Particle Variability Using Generalized Additive Models

High-resolution measurements of ultrafine particle concentrations in ambient air are needed for the study of health human effects of long-term exposure. This work, carried out in the framework of the VIEPI project (Integrated Evaluation of Indoor Particulate Exposure), aims to extend current knowledge on small-scale spatio-temporal variability of Particle Number Concentration (PNC, considered a proxy of the ultrafine particles) at a local scale domain (1 km × 1 km). PNC measurements were made in the university district of San Lorenzo in Rome using portable condensation particle counters for 7 consecutive days at 21 sites in November 2017 and June 2018. Generalized Additive Models (GAMs) were performed in the area for winter, summer and the overall period. The log-transformed two-hour PNC averages constitute the response variable, and covariates were grouped by urban morphology, land use, traffic and meteorology. Winter PNC values were about twice the summer ones. PNC recorded in the university area were significantly lower than those observed in the external routes. GAMs showed a rather satisfactory result in order to capture the spatial variability, in accordance with those of other previous studies: variances were equal to 71.1, 79.7 and 84%, respectively, for winter, summer and the overall period.

Measurement report: Three years of size-resolved eddy-covariance particle number flux measurements in an urban environment

Size-resolved particle number fluxes in the size range of 10 nm < particle diameter (Dp) < 200 nm were measured over a 3-year period (April 2017–March 2020) using the eddy-covariance technique at an urban site in Berlin, Germany. The observations indicated the site as a net source of particles with a median total particle number flux of FTNC=0.86 × 108 m−2 s−1. The turbulent surface–atmosphere exchange of particles was clearly dominated by ultrafine particles (Dp < 100 nm) with a share of 96 % of total particle number flux (FUFP=0.83 × 108 m−2 s−1). Annual estimates of median FTNC and FUFP slightly decreased by −9.6 % (−8.9 % for FUFP) from the first to the second observation year and a further −5.9 % (−6.1 % for FUFP) from the second to the third year. The annual variation might be due to different reasons such as the variation of flux footprints in the individual years, a slight reduction of traffic intensity in the third year, or a progressive transition of the vehicle fleet towards a higher share of low-emission standards or electric drive. Size-resolved measurements illustrated events of bidirectional fluxes, i.e. simultaneous emission and deposition fluxes within the size spectrum, which occurred more often in spring, late summer, and autumn than in winter. Multi-year observations of size-resolved particle fluxes proved to be important for a deeper understanding of particle exchange processes with the urban surface and the pronounced influence of traffic at this urban site.

Digital Holographic Microscopy as Identifier of Ultrafine Particles Emitted during Fused Deposition Modelling

Additive manufacturing has acquired a global industrial panorama for being an alternative to redirect the industry towards sustainability. However, previous studies have indicated that fused deposition modelling (FDM) techniques are potential sources of particles that are harmful to health. For this reason, this work is focused on exploring the behaviour and distribution of FDM resultant nanoparticles from the most commonly used printable materials through alternative methods as digital holographic microscopy (DHM). In this paper, we present the feasibility of using DHM to determine the presence of nanoparticles in the FDM process. Experimental results validate this technology’s precision and provide extensive knowledge about the implications of the FDM on health. The measure of the thin films deposited in glass substrates was between a minimum of 9 nm to a maximum of 200 nm, in agreement with the previous studies.

City Scale Modeling of Ultrafine Particles in Urban Areas with Special Focus on Passenger Ferryboat Emission Impact

Air pollution by aerosol particles is mainly monitored as mass concentrations of particulate matter, such as PM10 and PM2.5. However, mass-based measurements are hardly representative for ultrafine particles (UFP), which can only be monitored adequately by particle number (PN) concentrations and are considered particularly harmful to human health. This study examines the dispersion of UFP in Hamburg city center and, in particular, the impact of passenger ferryboats by modeling PN concentrations and compares concentrations to measured values. To this end, emissions inventories and emission size spectra for different emission sectors influencing concentrations in the city center were created, explicitly considering passenger ferryboat traffic as an additional emission source. The city-scale chemical transport model EPISODE-CityChem is applied for the first time to simulate PN concentrations and additionally, observations of total particle number counts are taken at four different sampling sites in the city. Modeled UFP concentrations are in the range of 1.5–3 × 104 cm−3 at ferryboat piers and at the road traffic locations with particle sizes predominantly below 50 nm. Urban background concentrations are at 0.4–1.2 × 104 cm−3 with a predominant particle size in the range 50100 nm. Ferryboat traffic is a significant source of emissions near the shore along the regular ferry routes. Modeled concentrations show slight differences to measured data, but the model is capable of reproducing the observed spatial variation of UFP concentrations. UFP show strong variations in both space and time, with day-to-day variations mainly controlled by differences in air temperature, wind speed and wind direction. Further model simulations should focus on longer periods of time to better understand the influence of meteorological conditions on UFP dynamics.