Aerosol particles, estimating exposures

Vemez (Switzerland) 2006 Application of waterproofing sprays Respirable aerosol particles containing solvent Exposure estimate range (mg/m )... 

Atmospheric conditions and particle size determine the persistence of aerosolized toxin in the environment. Temperature and humidity extremes facilitate toxin degradation, and smaller particles dissipate more quickly into the atmosphere. Studies estimate that aerosolized toxin would decay between less than 1 and 4% per minute. At a 1% decay rate, insubstantial amounts of toxin would remain after 2 days (36). Although botulinum toxin can penetrate mucosal surfaces, it cannot penetrate intact skin. If a release were recognized or announced, and authorities anticipated potential airborne exposure, people could protect themselves by covering their mouths and noses with clothing, such as underwear, shirts, scarfs, or handkerchiefs. In addition, after exposure, washing with soap and water would decontaminate clothing, and a 0.1% hypochlorite bleach solution would be effective on contaminated objects and surfaces (36). 

Information regarding absorption of PCBs in animals following inhalation exposure is limited. Male rats were exposed (whole body) to an aerosol of a PCB mixture, Pydraul A200 (42% chlorine), at a concentration of 30 g/m (0.5-3 pm particle diameter) for 2 hours (Benthe et al. 1972). After a 15-minute exposure, the PCB concentration in the liver was 40 pg/g tissue, and reached a maximum of 70 pg/g after 2 hours of exposure. These results provide qualitative information regarding absorption of this specific PCB mixture, but the data were not sufficient for estimating the amount or rate of absorption. It must be also mentioned that since exposure was not nose-only, the dermal route may have contributed to absorption. 

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