Fine aerosols particle exposure

Tippe AH, U. Roth, C. (2002) Deposition of fine and ultrafine aerosol particles during exposure at the air/cell interface. J Aerosol Sci 207-218... 

Sioutas C, Koutrakis P, Burton RM (1995) A technique to expose animals to concentrated fine ambient aerosols. Environ Health Perspect 103 172-177 Sioutas C, Delfino RJ, Singh M (2005) Exposure assessment for atmospheric ultrafine particles (UFPs) and implications in epidemiologic research. Environ Health Perspect 113 947-955 Southern Ontario Centre for Atmospheric Aerosol Research (SOCAAR) (2007) FacUities-Concentrated Ambient Particle Exposure Facility (CAPEF). http //www.socaar.utoronto.ca/ fac-inst/Facilities.htm. Accessed 21 September 2009 Squadrito GL, Cueto R, Dellinger B et al (2001) Quinoid redox cycling as a mechanism for sustained fiee radical generation by inhaled airborne particulate matter. Free Radic Biol Med 31 1132-1138... 

Respiratory protection is the most critical aspect of all protective clothing. The most common exposure route is the respiratory system. Most chemical agents are dispersed as an aerosol vapor or, in the case of biological or radiological agents, as small particles suspended in an aerosol. The atmosphere at explosion scenes will be very dusty (fine airborne particles). Working at an explosion scene requires respiratory protection, as this dust may contain asbestos or other toxic materials. 

Although respiratory protective devices and protective clothing fabrics are generally considered to provide adequate protection for exposures to fine-sized particulates, it is unclear whether these are effective barriers for nanoparticulates, defined as particulates with particle sizes <100 nm. Unfortunately, the currently available methodologies utilized in industrial hygiene practices to measure particle exposures also may not be sufficiently sensitive to measure occupational or ambient aerosol concentrations, whether in terms of particle mass, particle numbers or surface area. Therefore, it will be critical to develop a sensitive system to assess the barrier effectiveness or permeation of protective clothing fabrics, filters and respirators. 

Health effects attributed to sulfur oxides are likely due to exposure to sulfur dioxide, sulfate aerosols, and sulfur dioxide adsorbed onto particulate matter. Alone, sulfur dioxide will dissolve in the watery fluids of the upper respiratory system and be absorbed into the bloodstream. Sulfur dioxide reacts with other substances in the atmosphere to form sulfate aerosols. Since most sulfate aerosols are part of PMj 5, they may have an important role in the health impacts associated with fine particulates. However, sulfate aerosols can be transported long distances through the atmosphere before deposition actually occurs. Average sulfate aerosol concentrations are about 40% of average fine particulate levels in regions where fuels with high sulfur content are commonly used. Sulfur dioxide adsorbed on particles can be carried deep into the pulmonary system. Therefore, reducing concentrations of particulate matter may also reduce the health impacts of sulfur dioxide. Acid aerosols affect respiratory and sensory functions. 

Particles which find their way into the lungs can also have a negative effect on health. In the workplace and in our everyday lives, exposure to fine particle aerosols should be avoided. History has shown that exposure to coal dust, silica dust and asbestos dust, for example, can have disastrous effects on the health of workers many years after exposure. Many other workplace dusts, less well known, have been found to have negative health effects. 

Unlike the majority of chemical agents that are liquid at room temperature, modem RCAs are crystalline solids with low vapor pressure (see Table 11.1). RCAs are typically administered as fine particles, aerosol sprays, or in solutions therefore, they are not true gases. The inhalation toxicity of RCAs, as well as CWAs, is often indicated by the expression Ct. This term is defined as the product of concentration (C) in mg/m multiplied by exposure time (t) in minutes (mgmin/m ). LCt50 and... 

Sioutas C, Koutrakis P, Godleski JJ, Ferguson ST, Kim CS, Burton RM. Fine particle concentrators for inhalation exposures-effect of particle size and composition. J Aerosol Sci 1997 28 1057-1071. 

---