Computational modeling of multispecies aerosols generated from nucleating supersaturated vapors is a challenging task because of the complexity of the involved thermodynamic phenomena, non-existing validated and/or first principles-based models for the nucleation and condensation/evaporation processes, necessity for high computational effort, and, finally, lack of simulation data and software for validation

Heterogeneous nucleation constitutes the initial step in the formation of new aerosol particles that evolve on the surface of pre-existing (seed) particles. To this end the interaction of vapor and seed particle plays a critical role which is governed by the seed particle's size, composition, solubility, electrical charge state as well as the chemical nature of the vapor and the wetting properties

One of the most commonly employed instruments in the category of handheld condensation particle counters (CPCs) is the TSI 3007, which employs a simplified system for achieving a temperature difference between its saturator and its condenser in view of increasing portability, energy efficiency and autonomy. As a result, particle growth and consequently the detection efficiency of the instrument can

Collision frequencies of fractal clusters need to be modelled to predict cluster growth due to agglomeration. Here, we utilize Langevin dynamics to accurately capture the movement and collision of fractal agglomerates with various morphologies that are characterized by their size, fractal dimension, lacunarity and shape anisotropy in the free molecular regime. The simulations include rotational and

Over the past decade, there has been exponential growth in low-cost air pollution sensing technology. While low-cost sensors can provide a path towards more accessible air quality measurement, there are several guidelines that should be considered prior to deploying a low-cost sensor network. In this tutorial guide, we focus on low-cost aerosol sensors (in this case, PM2.5). The tutorial reviews key

Vehicle exhaust solid particle number emissions >23 nm (SPN23) and >10 nm (SPN10) were studied for 56 market light-duty vehicles with over 1000 laboratory tests. The studied vehicle-types were gasoline port-fueled injection (PFI), gasoline direct injection (GDI), GDI with gasoline particulate filter (GPF-GDI), and diesel equipped with particulate filter (DPF) vehicles. GDI and DPF SPN emissions decreased

We have recently developed a low-cost spark-induced breakdown spectroscopy (SIBS) instrument for in-situ analysis of toxic metal aerosol particles that we call TARTA (toxic-metal aerosol real time analyzer). In this work, we applied machine learning methods to improve the quantitative analysis of elemental mass concentrations measured by this instrument. Specifically, we applied least absolute shrinkage

In this paper, the characteristics of non-refractory aerosol using an International Civil Aviation Organization (ICAO) compliant sampling system emitted from two gas turbine relevant sources are reported, namely: an in-service turboshaft helicopter engine and a development combustor rig. Positive Matrix Factorisation (PMF) analysis was applied on an Aerosol Mass Spectrometer's (AMS) Unit Mass Resolution

Research interest in eliminating airborne aerosol particles has been growing for decades. Aerosol particles with aerodynamic diameters between 0.2 and 1 μm are difficult to remove by traditional spray systems. To improve the aerosol scavenging efficiency, a new method is proposed that employs the addition of water mist. Water mist is supposed to aggregate with aerosol particles to form large-sized

Aerosol particle scavenging by droplets is commonly seen in workplaces as a process of air depollution, but it is used in an empirical way. Although many studies have been conducted on this process, there is still a lack of data concerning its efficiency in the field of occupational health. Thus, an experimental study is presented in this paper, where a mist is sprayed in counter-current to an ascending

In view of the ongoing COVID-19 pandemic and its effects on global health, understanding and accurately modelling the propagation of human biological aerosols has become crucial. Worldwide, health professionals have been one of the most affected demographics, representing approximately 20% of all cases in Spain, 10% in Italy and 4% in China and US. Methods to contain and remove potentially infected

Nephelometers are regularly used for air quality monitoring through scattering measurements of aerosols in the atmosphere. Less attention has been paid to the potential of estimating soot morphological parameters from nephelometer measurements in combination with scattering theory. In this work, we perform a fundamental laboratory study where an Ecotech Aurora 3000 nephelometer is used for measuring

The filtration performance of three types of commercially available face masks (hygienic, surgical, and FFP2) has been evaluated for aerosol particle size in the range 10–150 nm at a fixed face velocity of 9.5 cm/s. Two parameters have been varied in this study: the time of use of the mask, and the electrical charging state of the particles. Mask aging has been carried out by wearing it for a prescribed

Due to the high variation of aerosol in space and time, remote sensing has become an effective tool in aerosol optical depth (AOD) retrieval. Most of the satellite-based AOD retrieval methods using the radiative transfer model (RTM). RTMs help to establish a relation between AOD and the observed top-of-atmosphere (TOA) reflectance. Using look-up table-based approaches is among the commonly used methods

COVID-19 is spread via different routes, including virus-laden airborne particles generated by human respiratory activities. In addition to large droplets, coughing and sneezing produce a lot of small aerosol particles. While face coverings are believed to reduce the aerosol transmission, information about their outward effectiveness is limited. Here, we determined the aerosol concentration patterns

Low-cost sensors for particulate matter mass (PM) enable spatially dense, high temporal resolution measurements of air quality that traditional reference monitoring cannot. Low-cost PM sensors are especially beneficial in low and middle-income countries where few, if any, reference grade measurements exist and in areas where the concentration fields of air pollutants have significant spatial gradients

Biomass burning (BB), a multi-step process including drying, devolatilization, and oxidation of volatiles and char, is a globally occurring phenomenon that is understood to produce significant quantities of aerosols that have a broad range of local and global effects on humans and the environment. Quantities and properties of BB-derived aerosols are difficult to predict due to the complex nature of

The measurement of airborne particles with sizes below 3 nm is critical, as it helps the understanding of atmospheric nucleation and elucidates important particle synthesis mechanisms in the gas phase. Condensation particle counters (CPCs) have been widely used to measure the concentration of aerosols. However, it is challenging for the CPCs to measure particles below 3 nm due to the insufficient activation

A dry-ambient aerosol size spectrometer (DAASS) was previously developed to conduct measurements of aerosol water content at ambient relative humidity (RH) conditions. However, the RH difference of ambient RH and DAASS conditioning humidity (i.e., 10–20%, particularly when the DAASS operated at a high ambient RH) may introduce uncertainties in estimation of aerosol water content. In this study, we

During the current COVID-19 pandemic, filtering-face-pieces and their certification get great attention from society. The determination of total filtration efficiency according to DIN EN 149/DIN EN 13274-7 (European standard for FFP1, FFP2 and FFP3 masks) has several drawbacks, making reliable certification of filtering-face-pieces difficult. This note analyses two of these drawbacks, namely the ambiguous

In this work, we introduce a new particle mass spectrometer (AP-PMS) that is able to detect particle-size distributions at ambient pressure using a three-stage pumping design. This device is demonstrated for direct sampling from the particle formation in spray-flame synthesis of iron oxide nanoparticles. Aerosol sampling is performed by a probe with integrated dilution that has been characterized and

In Operating Rooms (OR), the transport of Colony-Forming Units (CFU) can generate surgical site infections in patients and, as a consequence, CFU must be properly evacuated from the surgical site. Moreover, Fine Particles (FP) and UltraFine Particles (UFP) can be generated during surgeries by cutting and cauterizing surgical tools, with consequent effects on the health of patients and medical staff

Each year, healthcare settings are confronted by outbreaks caused by influenza and infected patients produce aerosols making this route a potential issue during outbreaks. This study was conducted in an Eastern Canadian hospital during three confirmed influenza outbreaks. Air was sampled in the rooms of infected patients using a liquid cyclone sampler and an electret dry filter sampler, two high flowrate

The acquisition of charge by aerosol particles is well-known to be stochastic in nature. We review the principles of charging using the conceptually and computationally clear language of continuous time Markov processes. A novel numeric approach is presented that can be used to calculate the time evolution of various particle charging processes. Its modular character makes it easy to implement and

In this paper, we report results on commuter's exposure to particulate matter (PM). Particle number concentrations (PNC) were recorded simultaneously inside and outside the cabin of a vehicle during 45 field trips in and around Paris (France) between 2016 and 2017. For a fixed ventilation setting, the impacts of external parameters were investigated to assess commuter's exposure for a wide range of

A Micro Smog Chamber (MSC) was coupled for the first time with a miniCAST 5201 Type BC combustion generator with the aim to produce a series of stable and reproducible model aerosols simulating the physical properties of combustion particles present in ambient air. With this setup it was possible to generate particles ranging from “fresh” soot (single scattering albedo SSA≤0.05, absorption Ångström

An axial cyclone separator with a spindle vane has the advantages of low pressure drop and high collection efficiency. Collection efficiency is an important parameter for assessing the performance of a cyclone separator. Previous studies have shown that as the number of turns of a spindle vane increases or the pitch of the spindle vane decreases, the collection efficiency of the axial cyclone separator

Monte Carlo simulations and integral equation techniques allow for the flexible and efficient computation of drag and diffusion coefficients for virus mimetic particles. We highlight a Monte Carlo method that is useful for computing the drag on biomimetic particles in the free-molecular regime and a numerical technique to solve a boundary integral equation (related to the Stokes equation) in the hydrodynamic

A model set of equations including Brownian rotation dynamics is proposed to investigate the role of rotation on the drift velocity of nanorods in the direction of an external field (such as electrical). Both inertial and non-inertial Brownian rotation are considered and the more realistic non-inertial shows more correlation between the rotational and translational motion. The average drift velocity

In this study, we present a traceable method for determining the counting efficiency of optical particle size spectrometers (OPSS), also known as aerosol spectrometers. The primary standard consists of an aerosol generation setup, a vertical flow tube for particle homogenization and a reference optical particle counter. The OPSS under testing and the reference optical particle counter sample aerosol

During the spray process, many factors control the disintegration of the liquid sheet at the exit of a nozzle operating in an ambient atmosphere. Understanding the role of these parameters has significant implications on the spray quality. In particular, in agricultural applications, the formation of finer spray droplets during breakup increases the risk of potential off-target movement of the spray

New particle formation (NPF) produces about 50% of the global cloud condensation nuclei in the troposphere. As such, NPF plays a crucial role in climate. Despite advancements in instrumentation capable of measuring freshly formed aerosol particles down to ~ 1 nm in diameter, the mechanisms behind NPF remain understudied due to the complex composition and chemistry of the atmosphere. Nucleation is the

Understanding the transmission phenomena of SARS-CoV-2 by virus-laden droplets and aerosols is of paramount importance for controlling the current COVID-19 pandemic. Detailed information about the lifetime and kinematics of airborne droplets of different size is relevant in order to evaluate hygiene measures like wearing masks but also social distancing and ventilation concepts for indoor environments

Inhaled viral droplets may immediately be expelled and cause an escalating re-transmission. Differences in the deposition location of inhaled viral droplets may have a direct impact on the probability of virus expelling. This study develops a numerical model to estimate the region-specific deposition fractions for inhalable droplets (1-50 μ m) in respiratory airways. The results identified a higher

Abstract The SAE International has published Aerospace Information Report (AIR) 6241 which outlined the design and operation of a standardized measurement system for measuring non-volatile particulate matter (nvPM) mass and number emissions from commercial aircraft engines. Prior to this research, evaluation of this system by various investigators revealed differences in nvPM mass emissions measurement

Abstract In this report, a flame spray pyrolysis setup has been examined with various in situ extraction methods of particle samples along the flame axis. First, two precursor formulations leading to the formation of iron oxide nanoparticles were used in a standardized SpraySyn burner system, and the final particle outcome was characterized by a broad range of established powder characterization techniques

Simulating an evolving aerosol population in a reactor containment is essential for estimating the radioactivity that is possible to leak to the environment. In this study, a sectional model is developed to simulate multi-component aerosol dynamics in the containment during severe accidents of a pressurized water reactor by improving the widely used MAEROS (Multicomponent AEROSol) model. An important

Indoor respirable suspended particles may accumulate on textured surfaces such as sofa surfaces and office partitions via particle deposition. Previous studies mainly focus on particle deposition on non-patterned rough surfaces or patterned surfaces with texture scale larger than millimeters, and it is generally concluded that deposition rate increases due to the roughness. However, many indoor surfaces

In collaboration with 16 musicians from the Minnesota Orchestra, we assess the airflow and particle concentration emitted from ten wind instruments under realistic performance conditions. Anemometer and schlieren measurement techniques are used to quantify the air flow, and aerodynamic particle sizer, laser sheet, and digital inline holography techniques are used to measure the particle concentration

In China particulate matter (PM) is the leading environmental risk factor to morbidity and mortality, with transport being the main source of PM pollution in cities. China VI emission limit standards, which are one of the most stringent worldwide, have only recently been introduced and there is lack of studies assessing the PM emissions of new engines. In Europe, there are discussions ongoing to permit

The detachment of particle structures from a stiff single fiber exposed to an airflow has been investigated by (Jankowska et al., 2000; Larsen, 1958; Löffler, 1972; Przekop et al., 2004; Qian et al., 1997; Zoller et al., 2020). In order to detach particle piles from a stiff single fiber, airflow velocities above 1.2 m/s are required. While these values are well above typical operational parameter for

Aerosol deposition from laminar flow in a horizontal circular tube is studied analytically considering the combined mechanisms of Brownian diffusion and gravitational settling, and the mean concentration and deposition velocity are calculated and analyzed by using the theoretical solution. The results show that when both diffusional and gravitational effects are considered, the deposition velocity