The Aerodynamic Aerosol Classifier (AAC) and Differential Mobility Analyzer (DMA) are aerosol classifiers commonly used to generate a monodispersed aerosol by selecting particles within a narrow range of relaxation times or electrical mobilities, respectively. However, generating an aerosol of homogeneous particles, which has narrow ranges of particle mass, mobility and relaxation time simultaneously

This pilot study evaluated the ability of a lung deposition sampler (LDS) to estimate body burden by comparing lung-deposited and inhalable nickel and chromium exposures to biomarkers of internal dose. A cohort of stainless steel welders (N = 18) wore side-by-side inhalable and lung deposition samplers for two Monday shifts and urine samples were collected pre- and post-shift. Samplers were analyzed

Low-cost particle sensors are rapidly gaining popularity for indoor air quality monitoring, but their accuracy has been shown to vary among products and among environments in which they operate. Previous research has explored the effect of environmental conditions including temperature and humidity on sensor accuracy and found appreciable effects of these variables in many cases. We extend this work

The use of low-cost air pollution sensors mounted on drones is an exciting new approach to conduct affordable and highly resolved air quality measurements. However, the air flow around a drone consists of complex, unsteady turbulent structures which interact directly with ambient particulate matter and gases. These interactions influence the transport of fine particulate matter (e.g. PM2.5) and, subsequently

Inhalation exposure to environmental and occupational aerosol contaminants is associated with many respiratory health problems. To realistically mimic long-term inhalation exposure for toxicity testing, lung epithelial cells need to maintained and exposed under air-liquid interface (ALI) conditions for a prolonged period of time. In addition, to study cellular responses to aerosol particles, lung epithelial

Studies on the flow-induced particle resuspension have great significance for engineering applications of many areas, and several established resuspension models have been developed for the analysis of particle resuspension in an atmospheric environment. However, for flow with a non-negligible particle Knudsen number (the ratio between the mean free path of gas and the particle radius), which is commonly

Particle shape strongly influences the diffusion charging of aerosol particles exposed to bipolar/unipolar ions and accurate modeling is needed to predict the charge distribution of non-spherical particles. A prior particle-ion collision kernel βi model including Coulombic and image potential interactions for spherical particles is generalized for arbitrary shapes following a scaling approach that

In 2017, Assembly Bill 617 was approved in state of California, which mandated the allocation of resources for addressing air pollutant exposure disparities in underserved communities across the state. The bill stipulated the implementation of community scale monitoring and the development of local emissions reductions plans. We aimed to develop a streamlined, robust, and accessible PM2.5 exposure

Correlating data from in vitro dissolution testing of inhaled particulate pharmaceuticals or air pollutants with the dissolution and distribution to the blood circulation of the same aerosols following inhalation in vivo is a major challenge. Better methods could benefit both inhaled drug development and the risk assessment of air pollutants. Five properties known to influence the results produced

The resolidified fuel debris from the damaged Fukushima Daiichi reactors must be cut into small pieces prior to removing it from reactor buildings. Submicron radioactive aerosol particles are likely to be generated and dispersed into the primary containment vessel (PCV) atmosphere during this cutting process. However, traditional sprays cannot effectively scavenge aerosol particles with diameters in

Activities such as the suppression of coal dust would benefit from an improved understanding about how the presence of surfactant alters the charge distribution of spray drops. However, there is no standard method to measure charge and size distributions of nozzle-generated spray drops. To fill this gap, a new spray drop charge measurement system was developed to measure a broad range of sizes and

Particulate matter (PM) sensors are popular for distributed monitoring due to their portability, low-cost and networking capabilities. To provide reliable data, these sensors have to be calibrated periodically in the laboratory. This is often done in chambers with several of them co-located, alongside several research grade instruments. It is important to confirm that the aerosol is well distributed

Dynamic modeling of how particulate matter (PM) transport, deposit, and translocate from human respiratory systems to systemic regions subject to indoor and outdoor exposures are essential for case-specific lung dosimetry predictions and occupational health risk assessments. Because of the invasive nature and imaging resolution limitations of existing in vitro and in vivo methods, Computational Fluid-Particle

Electrical Mobility is arguably the property upon which some of the most successful classification criteria are based for aerosol particles and ions in the gas phase. Once the value of mobility is empirically obtained, it can be related to a geometrical descriptor of the charged entity through a size-mobility relationship. Given the multiscale range of sizes in the aerosol field, approaches that can

Structural properties in nonwoven materials, such as porosity and layer thickness, are typically spatially distributed on a micro- and mesoscale. The mesoscale inhomogeneity is visually perceived, inter alia, as the cloudiness of the nonwoven fabric or as inclusions in the bulk material. Differential box counting, which is a fractal based image analysis method, was used to assess the inhomogeneity

A recently described DMA designed for high resolution viral particle analysis (Perez-DMA; Perez-Lorenzo et al, 2020) is modified to decrease the relative peak full width at half maximum (FWHM) below previously achieved ≈3.3%. The electrode radii at the outlet slit (R1 = 1.01 cm; R2 = 2 cm) and the working length are almost unchanged (L = 114.9 vs. 116 mm). The laminarization trumpet and the radius

Gas phase nucleation is a universal phenomenon that plays a crucial role in both natural settings and industrial processes. Despite more than 100 years’ work to decipher this highly dynamic process, our understanding of nucleation remains incomplete. In particular, the formation, decay, and structures of the initially formed nucleating clusters critically determine the overall behavior of the nucleation

Traditional in vivo inhalation studies to inform hazard identification and risk assessment are time-intensive and financially expensive. Cell culture models combined with aerosol exposure systems have shown promise as surrogates in screening assays when multiple substances require preliminary information on hazard potential associated with aerosolized materials. This paper presents two different aerosol

We investigated a spray-drying aerosol generator that can generate micro-particles at high concentration using an ultrasonic nozzle. Unlike a conventional spray-drying aerosol generator that uses vertical spray with co-current sheath flow, we designed a new aerosol generator by using horizontal spray with co-current sheath flow combined with clean counter flow to increase particle generation efficiency

We report the photodegradation of optically trapped oleic acid droplets by visible light in the absence of additional reactive gaseous species. The temporal evolution of the droplet's chemical composition and size is monitored by Raman spectroscopy and elastic light scattering, respectively. The dependencies on the oxygen amount in the surrounding gas phase (~0–20%), the droplet size (~500–3000 nm

The transport and deposition of inhaled micron particles is largely determined by their inlet conditions, breathing rate, and the individual airway geometry. In this study, helical air-particle flow is introduced which significantly affects the particle dynamics with applications to targeted drug delivery. Specifically, helical flow, which reduces axial momentum, can be controlled by varying the swirl

A differential mobility analyzer along with a centrifugal particle mass analyzer was employed to study the effect of fuel type on effective density for nascent and non-volatile particles generated by a marine diesel engine. The engine was operated at 1500 rpm at loads between 10% and 100%. Three different fuels were evaluated: diesel fuel, distillate marine oil Grade A, and intermediate fuel oil. A

Hygroscopic growth of aerosols plays an important role in the characterization of atmospheric aerosols. Physico-chemical and optical properties of aerosols are dependent on relative humidity (RH) as well as on their size and composition. In this study, scattering enhancement factors, f(RH), for polydispersed aerosols were approximated. f(RH) of ammonium sulfate and ammonium nitrate (AS) and NaCl aerosols

The lack of quantitative risk assessment of airborne transmission of COVID-19 under practical settings leads to large uncertainties and inconsistencies in our preventive measures. Combining in situ measurements and computational fluid dynamics simulations, we quantify the exhaled particles from normal respiratory behaviors and their transport under elevator, small classroom, and supermarket settings

The potential airborne transmission of COVID-19 has raised significant concerns regarding the safety of musical activities involving wind instruments. However, currently, there is a lack of systematic study and quantitative information of the aerosol generation during these instruments, which is crucial for offering risk assessment and the corresponding mitigation strategies for the reopening of these

In vitro studies are the first step toward understanding the biological effects of particulate matter. As a more realistic exposure strategy than submerged culture approaches, air-liquid interface (ALI) in vitro exposure systems are gaining interest. One challenge with ALI systems is determining accurate particle mass deposition. Although a few commercially available ALI systems are equipped with online

Residential wood combustion, which is characterized by incomplete combustion, is a common source of particulate matter in suburban areas. This study investigated the usability of three different scattering-based particulate matter (PM) sensors and an absorption-based black carbon (BC) sensor in an environment impacted by wood combustion emissions. The measurement campaign, which lasted approximately

Preferential particle orientation has been previously reported for desert dust and attributed on atmospheric electricity (Ulanowski et al., 2007). Depending on its strength, the total electric field within the dust layer can: (a) counteract the gravitational settling of large particles and (b) cause a preferential orientation of the non-spherical particles along the vertical direction (Fucks, 1958;

Nasal airway obstruction (NAO) is one of the main problems in the upper part of the human respiratory system. NAO may considerably affect the airflow and the behavior of droplets in the nasal cavity. In the present study, the effect of septal deviation as a special kind of NAO on the deposition and penetration of initially micron-sized inhaled droplets in the nasal cavities of two patients was numerically

The inhalation route has a substantial influence on the fate of inhaled particles. An outbreak of infectious diseases such as COVID-19, influenza or tuberculosis depends on the site of deposition of the inhaled pathogens. But the knowledge of respiratory deposition is important also for occupational safety or targeted delivery of inhaled pharmaceuticals.

The micro-cold spray process produces thick patterned films by impacting powders consisting of nano-to-sub-micron particles at velocities from 300 to over 1400 m/s. This process has been used extensively to produce ceramic films but has been employed only on a very limited basis to produce metallic films. The fine powders used in micro-cold spray are invariably agglomerated to some degree, but the

A method for trace analysis of aerosol mineral components using quantum cascade laser (QCL) based infrared absorption spectroscopy is described. The measurement approach involves: (a) collection of aerosol on a particulate filter; (b) sample treatment using low-temperature oxygenated plasma to minimize the matrix interferences; (c) redeposition of the treated sample as a dried spot for direct-on-filter

Aim There is a need to bridge the data gap concerning the regional deposition of electronic nicotine delivery systems (ENDS) emissions in the airways. The present work aims to experimentally and precisely asses the aerosol regional deposition of ENDS emissions using an ex vivo model of lungs as a complementary approach to a determinist computational model and as an alternative to animal or human in

The development of predictive aerosol dosimetry models has been a major focus of environmental toxicology and pharmaceutical health research for decades. One-dimensional (1D) models successfully predict overall deposition averages but fail to accurately predict local deposition. Computational fluid-particle dynamics (CFPD) models provide site-specific predictions but at a computational cost that prohibits

The synthesis of nanoparticles by reaction of liquid aerosol droplets containing precursors in a flow-through, atmospheric-pressure, non-thermal plasma offers a continuous, scalable, substrate- and stabilizer-free approach for direct deposition into liquids or onto soft substrates. However, the combination of multiphase and non-equilibrium chemistry makes the process complicated and poorly understood

Baghouse filters are widely applied in industrial gas cleaning, for example in waste incineration plants and the cement industry, to meet particle emission standards and for product recovery. The global particle emission of pulse-jet cleaned surface filters is typically monitored end of pipe (e.g. in the stack). Since the particulate matter emission of baghouse filters originates often from leaks and

Laboratory animals are often used to derive health risk from environmental exposure or to assess the therapeutic effect of a drug delivered by inhaled therapy. Knowledge of the in-situ distribution of deposited particles on airway and alveolar surfaces is essential in any assessment of these effects. A unique database including both high-resolution lung anatomy and deposition data in four strains of

The effects of non sphericity and particle orientation on mineral dust gravitational settling are studied for prolate spheroids in the range of Reynolds number up to 100. New drag coefficients for prolate spheroids are defined that take into account the orientation of the particle. The drag coefficients along with the slip correction factors are applied to the momentum equation, which is numerically

Particulate matter (PM) released from industrial emissions could cause health problems, which are strongly associated with the chemical composition of PMs. This study aimed to estimate the unknown contribution of two iron industries using a known iron plant via sensitivity analysis. For this purpose, a comprehensive analysis was carried out on the characteristics of known iron plant, accessible sampling

Filtering the air entering swine farms has significantly reduced the incidence of porcine reproductive and respiratory syndrome virus (PRRSv) infections in Midwestern breeding herds. Despite the significant investment made in installation of air filters, the nature and type of viruses trapped by these filters are not yet clear because of the unavailability of reliable methods to elute and detect these