A comparative study of challenge aerosols was conducted to review a performance test for dust respirators. The national approval test for dust respirator certification in Japan requires that air containing quartz particles of smaller than 2 pm in diameter should be used as the test aerosol. Aerosols with broad size distributions may therefore be used as the test aerosols. In view of the interna...

An aerosol generation, calibration, and research facility has been developed with the major purpose of evaluating aerosol instrumentation, including quality assurance testing, intercomparison, performance evaluation, and calibration of aerosol sizing, bulk, and speciated mass-measuring instruments. The aerosol facility also provides excellent opportunities for basic aerosol research. Polydisper...

In this paper, we present the development of a method to accurately measure the positive and negative charge distribution of nanosized aerosols using a tandem differential mobility analyzer (TDMA) system. From the series of TDMA measurements, the charge fraction of nanosized aerosol particles was obtained as a function of equivalent mobility particle diameter ranging from 50 to 200 nm. The capa...

Aerosol particles attached to cloud droplets are much more likely to be removed from the atmosphere and are much less efficient at scattering sunlight than if unattached. Models used to estimate direct and indirect effects of aerosols employ a variety of representations of such cloud-borne particles. Here we use a global aerosol model with a relatively complete treatment of cloud-borne particle...

Air filters efficiency is usually determined by non-biological test aerosols, such as potassium chloride particles, Arizona dust or di-ethyl-hexyl-sebacate (DEHS) oily liquid. This research was undertaken to asses, if application of non-biological aerosols reflects air filters capacity to collect particles of biological origin. The collection efficiency for non-biological aerosol was tested wit...

As part of the OSOA (Origin and formation of Secondary Organic Aerosols) project, two intensive field campaigns were conducted in Melpitz, Germany and Hyytiälä, Finland. This paper gives an overview of the measurements made during the Hyytiälä campaign, which was held between 1 and 16 August 2001. Various instrumental techniques were used to achieve physical and chemical characterisation of aer...

All naturally occurring and most man-made solid particles are nonspherical. Examples include air-pollutants in the nano- to micro-meter range as well as blood constituents, drug particles, and industrial fluid-particle streams. Focusing on the modeling and simulation of inhaled aerosols, theories for both spherical and nonspherical particles are reviewed to analyze the contrasting transport and...

Diseases can be transmitted via many routes, including inhalation of aerosols. When properly fitted and maintained, particulate-removing respirators have been demonstrated to reduce the amount of aerosols – both bioaerosols and nonbiological aerosols – that are inhaled by the wearer. In contrast, most surgical masks are not designed to seal tightly to the face, and research has shown that they ...

Atmospheric aerosols, suspensions of solid or liquid particles, are an important multiphase system. Aerosols scatter and absorb shortwave (solar) radiation, affecting climate (Charlson et al., 1992; Schwartz, 1996) and visibility; nucleate cloud droplet formation, modifying the reflectivity of clouds (Twomey et al., 1984; Schwartz and Slingo, 1996) as well as contributing to composition of clou...