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The generation of diesel exhaust particle aerosols from a bulk source in an aerodynamic size range similar to atmospheric particles.

Cooney DJ, Hickey AJ - Int J Nanomedicine (2008)

Bottom Line: Inertial impaction data indicated that the particle size distributions of the generated aerosols were trimodal, with count median aerodynamic diameters less than 100 nm.Scanning electron microscopy of deposited particles showed tightly aggregated particles, as would be expected from an evaporative process.Chemical analysis indicated that there were no major changes in the mass proportion of 2 specific aromatic hydrocarbons (benzo[a]pyrene and benzo[k]fluoranthene) in the particles resulting from the aerosolization process.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC, USA. cooneyinsf@gmail.com

ABSTRACT
The influence of diesel exhaust particles (DEP) on the lungs and heart is currently a topic of great interest in inhalation toxicology. Epidemiological data and animal studies have implicated airborne particulate matter and DEP in increased morbidity and mortality due to a number of cardiopulmonary diseases including asthma, chronic obstructive pulmonary disorder, and lung cancer. The pathogeneses of these diseases are being studied using animal models and cell culture techniques. Real-time exposures to freshly combusted diesel fuel are complex and require significant infrastructure including engine operations, dilution air, and monitoring and control of gases. A method of generating DEP aerosols from a bulk source in an aerodynamic size range similar to atmospheric DEP would be a desirable and useful alternative. Metered dose inhaler technology was adopted to generate aerosols from suspensions of DEP in the propellant hydrofluoroalkane 134a. Inertial impaction data indicated that the particle size distributions of the generated aerosols were trimodal, with count median aerodynamic diameters less than 100 nm. Scanning electron microscopy of deposited particles showed tightly aggregated particles, as would be expected from an evaporative process. Chemical analysis indicated that there were no major changes in the mass proportion of 2 specific aromatic hydrocarbons (benzo[a]pyrene and benzo[k]fluoranthene) in the particles resulting from the aerosolization process.

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Related in: MedlinePlus

Diagram of potential droplet formation followed by evaporation yielding three different aerosol size modes.
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f5-ijn-3-435: Diagram of potential droplet formation followed by evaporation yielding three different aerosol size modes.

Mentions: The mass and number-based particle size distributions appear to be bimodal, but when taken together indicate a probable trimodal aerosol particle size distribution. There were large numbers of nanoparicles (NM1) that would not be seen in the data from the NVCI because particles in this size range are too small to deposit in the device and contain very little mass. NM2 likely represents the same particle mode that is represented by MM1. The shift in location on the particle diameter axis from NM2 (~0.2–0.3 μm) to MM1 (0.5–1.5 μm) is typical of particle size distributions based on number and mass [mass ∝ (number × diameter3)]. The number of particles contained in MM2 was likely too small for that mode to be seen in the ELPI data. The size distributions of suspension MDI aerosols are functions of the initial droplet sizes and the number of suspended particles and dissolved material that each droplet contains. If the aerosol particle size distribution was trimodal, the initial droplet distribution was likely trimodal. A diagram of the potential size distribution of droplets and final aerosol particles is shown in Figure 5. It has been shown previously that some HFA134a pressurized metered dose inhaler aerosols have multi-modal droplet size distributions (Smyth and Hickey 2003).


The generation of diesel exhaust particle aerosols from a bulk source in an aerodynamic size range similar to atmospheric particles.

Cooney DJ, Hickey AJ - Int J Nanomedicine (2008)

Diagram of potential droplet formation followed by evaporation yielding three different aerosol size modes.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2636590&req=5

f5-ijn-3-435: Diagram of potential droplet formation followed by evaporation yielding three different aerosol size modes.
Mentions: The mass and number-based particle size distributions appear to be bimodal, but when taken together indicate a probable trimodal aerosol particle size distribution. There were large numbers of nanoparicles (NM1) that would not be seen in the data from the NVCI because particles in this size range are too small to deposit in the device and contain very little mass. NM2 likely represents the same particle mode that is represented by MM1. The shift in location on the particle diameter axis from NM2 (~0.2–0.3 μm) to MM1 (0.5–1.5 μm) is typical of particle size distributions based on number and mass [mass ∝ (number × diameter3)]. The number of particles contained in MM2 was likely too small for that mode to be seen in the ELPI data. The size distributions of suspension MDI aerosols are functions of the initial droplet sizes and the number of suspended particles and dissolved material that each droplet contains. If the aerosol particle size distribution was trimodal, the initial droplet distribution was likely trimodal. A diagram of the potential size distribution of droplets and final aerosol particles is shown in Figure 5. It has been shown previously that some HFA134a pressurized metered dose inhaler aerosols have multi-modal droplet size distributions (Smyth and Hickey 2003).

Bottom Line: Inertial impaction data indicated that the particle size distributions of the generated aerosols were trimodal, with count median aerodynamic diameters less than 100 nm.Scanning electron microscopy of deposited particles showed tightly aggregated particles, as would be expected from an evaporative process.Chemical analysis indicated that there were no major changes in the mass proportion of 2 specific aromatic hydrocarbons (benzo[a]pyrene and benzo[k]fluoranthene) in the particles resulting from the aerosolization process.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC, USA. cooneyinsf@gmail.com

ABSTRACT
The influence of diesel exhaust particles (DEP) on the lungs and heart is currently a topic of great interest in inhalation toxicology. Epidemiological data and animal studies have implicated airborne particulate matter and DEP in increased morbidity and mortality due to a number of cardiopulmonary diseases including asthma, chronic obstructive pulmonary disorder, and lung cancer. The pathogeneses of these diseases are being studied using animal models and cell culture techniques. Real-time exposures to freshly combusted diesel fuel are complex and require significant infrastructure including engine operations, dilution air, and monitoring and control of gases. A method of generating DEP aerosols from a bulk source in an aerodynamic size range similar to atmospheric DEP would be a desirable and useful alternative. Metered dose inhaler technology was adopted to generate aerosols from suspensions of DEP in the propellant hydrofluoroalkane 134a. Inertial impaction data indicated that the particle size distributions of the generated aerosols were trimodal, with count median aerodynamic diameters less than 100 nm. Scanning electron microscopy of deposited particles showed tightly aggregated particles, as would be expected from an evaporative process. Chemical analysis indicated that there were no major changes in the mass proportion of 2 specific aromatic hydrocarbons (benzo[a]pyrene and benzo[k]fluoranthene) in the particles resulting from the aerosolization process.

Show MeSH
Related in: MedlinePlus