Toward Developing A New Occupational Exposure Metric Approach for Characterization of Diesel Aerosols

Abstract

The extensive use of diesel-powered equipment in mines makes the exposure to diesel aerosols a serious occupational issue. The exposure metric currently used in U.S. underground noncoal mines is based on the measurement of total carbon (TC) and elemental carbon (EC) mass concentration in the air. Recent toxicological evidence suggests that the measurement of mass concentration is not sufficient to correlate ultrafine aerosol exposure with health effects. This urges the evaluation of alternative measurements. In this study, the current exposure metric and two additional metrics, the surface area and the total number concentration, were evaluated by conducting simultaneous measurements of diesel ultrafine aerosols in a laboratory setting. The results showed that the surface area and total number concentration of the particles per unit of mass varied substantially with the engine operating condition. The specific surface area (SSA) and specific number concentration (SNC) normalized with TC varied two and five times, respectively. This implies that miners, whose exposure is measured only as TC, might be exposed to an unknown variable number concentration of diesel particles and commensurate particle surface area. Taken separately, mass, surface area, and number concentration did not completely characterize the aerosols. A comprehensive assessment of diesel aerosol exposure should include all of these elements, but the use of laboratory instruments in underground mines is gener-

Ultrafine Particle Generation through Atomization Technique: The Influence of the Solution

“…Even if the regulatory authority policies to reduce people exposure to particles are still mostly based on particle mass concentration standards, PM 10 or PM 2.5 (U.S. Environmental Protection Agency, 1997; European Committee for Standardization, 2001; European Committee for Standardization, 2005;European Commission, 2008;European Parliament and Council, 2008;European Parliament and Council, 2010;Buonanno et al, 2011a), during the last years the scientific community is focusing on new exposure metrics mainly related to sub-micrometric and ultrafine particles (UFPs) such as particle number (Franck et al, 2011) and surface area concentrations (Giechaskiel et al, 2009a;Cauda et al, 2012).…”

A simplified benchmark of ultrafine particle dispersion in idealized urban street canyons: A wind tunnel study

“…Future development of the study will be focused on the evaluation of influential parameters on particle exposure in urban microenvironments using the on-scale approach here proposed: as example, street canyon geometry (different aspect ratios, asymmetric canyons), presence of roadside vegetation barriers, and wind directions and velocities will be investigated. To this end the scalability of the fluid-dynamic and particle aerodynamics will be investigated in order to provide particle exposure scenarios representative Percentage difference with respect to the mid-length concentration (x=0 cm) - 5 5.73 ± 0.11 × 10 6 -22% -2. 5 6.90 ± 0.08 × 10 6 -5% 0 7.30 ± 0.05 × 10 6 -2.…”

“…To this end the scalability of the fluid-dynamic and particle aerodynamics will be investigated in order to provide particle exposure scenarios representative Percentage difference with respect to the mid-length concentration (x=0 cm) - 5 5.73 ± 0.11 × 10 6 -22% -2. 5 6.90 ± 0.08 × 10 6 -5% 0 7.30 ± 0.05 × 10 6 -2. 5 7.16 ± 0.04 × 10 6 -2% 5…”

Physiological Responses to Acute Airborne Particle Exposure during Maximal Aerobic Power

“…Particle surface area metric was chosen as it was recently suggested to have a more direct relationship with inhalation toxicity than particle mass concentration (Giechaskiel et al, 2009;Cauda et al, 2012;Oberdörster, 2001;Sze-To et al, 2012). Doses received by each subject were estimated from the alveolar deposited surface area concentration measured through the NanoTracer.…”