The counting efficiency as a function of particle size has been calculated for a particular forward scattering aerosol particle counter that uses white light illumination for spherical particles with indexes of refraction 1.33-0i, 1.40-0i, 1.50-0i, 1.592-0i, 1.50-0.05i, 1.50-0.1i, 1.50-0.5i, and 1.95-0.66i. The counting efficiency differs from 100% because of statistical effects: photoelectron ...

A recirculation aerosol wind tunnel was designed to maintain a uniform airflow and stable aerosol size distribution for evaluating aerosol sampler performance and determining particle penetration through protective clothing materials. The oval-shaped wind tunnel was designed to be small enough to fit onto a lab bench, have optimized dimensions for uniformity in wind speed and particle size dist...

The effect of vapor-wall deposition on secondary organic aerosol (SOA) formation has gained significant attention; however, uncertainties in experimentally derived SOA mass yields due to uncertainties in particle-wall deposition remain. Different approaches have been used to correct for particle-wall deposition in SOA formation studies, each having its own set of assumptions in determining the ...

.........................................................................................................................3 INTRODUCTION ................................................................................................................5 DIESEL ENGINE TECHNOLOGY AND EMISSION REGULATIONS .............................7 PHYSICAL AND CHEMICAL NATURE OF DIESEL AEROSOL ......................

BACKGROUND The optimal particle size of a beta 2 agonist or anticholinergic aerosol in patients with severe airflow obstruction is unknown. METHODS Seven stable patients with a mean forced expiratory volume in one second (FEV1) of 37.9% of the predicted value inhaled three types of monodisperse salbutamol and ipratropium bromide aerosols with particle sizes of 1.5 microns, 2.8 microns, and 5 ...

[1] Secondary organic aerosol (SOA) formed from partitioning of oxidation products of anthropogenic and biogenic volatile organic compounds (VOCs) accounts for a substantial portion of atmospheric particulate matter. In describing SOA formation, it is generally assumed that VOC oxidation products rapidly adopt gas-aerosol equilibrium. Here we estimate the equilibration timescale, teq, of SOA ga...

This paper presents a mechanistic, fully dynamic, internally mixed, sectional aerosol module, the UCD Aerosol Module, which evolves from the Aerosol Inorganic Model (AIM). The UCD Aerosol Module employs three gas-to-particle mass transport schemes, replacement, coupled and uncoupled, and simplified aerosol thermodynamics to predict gas–particle partitioning, aerosol phase state and water conten...

The Coastal Aerosol Transport (CAT) model was developed to study the evolution of aerosol particle size distributions and composition in the coastal environment. The model simulates such processes as particle production at the sea surface, mixing of particles through the boundary layer by turbulent diffusion, gravitational settling, and dry deposition. The model is initialized at the shoreline ...

A new aerosol microphysical module MATRIX, the Multiconfiguration Aerosol TRacker of mIXing state, and its application in the Goddard Institute for Space Studies (GISS) climate model (ModelE) are described. This module, which is based on the quadrature method of moments (QMOM), represents nucleation, condensation, coagulation, internal and external mixing, and cloud-drop activation and provides...

A three-dimensional, size-resolved and chemically resolved aerosol model is developed. Gas-to-particle conversion is represented by dynamic mass transfer between the gas and aerosol phases. Particle-phase thermodynamics is computed by a new thermodynamic model, Simulating Composition of Atmospheric Particles at Equilibrium 2. The aerosol model is applied to simulate gas and aerosol behavior in ...