Dust aerosol

Toxic, flammable/explosive, reactive, unstable Liquid, solid (briquette, flake, powder), gas, vapour, ah-borne particulate (including mist, fume, froth, aerosol, dust)... 

Exposures to chemicals may involve solids, liquids, or airborne matter as mists, aerosols, dusts, fumes (i.e. pm-sized particulates), vapours or gases in any combination. Many situations, e.g. exposure to welding fumes or to combustion products from fossil fuels, include mixtures both of chemicals and of physical forms. Quantification of exposure is then difficult. 

Monitor for airborne dust (surfaee or subsurfaee soil) with portable, aerosol dust direet reading instruments. 

Figure 4-2. Particle-size ranges for aerosols, dusts, and fumes. Courtesy, H. P. Munger, Bat-telle Memorial Institute.

Armstrong, D.W., Kullman, J.P., Chen, X., Rowe, M. (2001). Composition and chirality of amino acids in aerosol/dust from laboratory and residential enclosures. Chirality 13, 153-158. 

Xnormal normal or total respirable aerosol dust concentration,... 

Occupational exposure to nickel may occur by dermal contact or by inhalation of aerosols, dusts, fumes, or mists containing nickel. Dermal contact may also occur with nickel solutions, such as those used in electroplating, nickel salts, and nickel metal or alloys. Nickel-containing dust may be ingested where poor work practices exist or poor personal hygiene is practiced. A National Occupational Exposure Survey (NOES) conducted by NIOSH from 1981 to 1983 estimates that 727,240 workers are potentially exposed to some form of nickel metal, alloys, salts, or inorganic nickel compounds in the United States (NIOSH 1990). The form of nickel these workers were probably exposed to and the level of exposure for different industries and operations were reviewed by Warner (1984) and lARC (1990). 

Only one study was located regarding death in animals after inhalation exposure to DNOC aerosols (Burkatskaya 1965a). In this study, I of 3 and 2 of 6 cats died after being exposed to 40 and 100 mg/m of an aerosol of DNOC solution for 4 hours, respectively. Two of six cats died after being exposed to 100 mg/m DNOC solid aerosols (dusts). The data suggest that the DNOC solution aerosol was no more toxic than the dust. In addition, 2 of 3 cats died after being exposed to an aerosol of 2.0 mg/m DNOC in solution 4 hours/day for 1 month. 

Grin H. and Lein V., Aerosols - dusts, smokes and fogs. Leningrad, Gidrometeoizdat, 1969, 427 pp. (in Russian). 

A number of studies have speculated on diazotroph response to mineral dust Fe fertilization in the Atlantic (Mahaffey et al, 2003), and Pacific Oceans (Johnson et al, 2003). Circumstantial evidence for dust stimulation of marine diazotrophic biomass has recently been reported. A 1999 Saharan dust event coincided with increases in dissolved Fe concentrations on the west Florida shelf and a 100-fold increase in Trichodesmium biomass. N2 fixation rates were not measured, but DON concentrations doubled, presumably due to exudation by N2 fixers (Lenes et al, 2001). A recent Saharan dust addition experiment to surface water samples collected along a west African cruise transect (35°W-17°W), found a minimal increase in CO2 fixation and a large stimulation in N2 fixation, suggesting that diazotrophs were co-limited by both P and Fe (Mills et al, 2004). Note however, analysis of aerosol dust shows that while providing Fe, it also supplies P and combined N (Baker et al, 2003 Mills et al, 2004 Ridame and Guieu, 2002). 

The pathways of radionuclides in ecosystems are illustrated schematically in Fig. 21.2. Plants may take up radionuclides from the air by deposition on the leaves, or from the soil by the roots with water and minerals. In this step, the species of the radionuclides and their solubility are most important. Microorganisms incorporate radionuclides present in water or in the soil. Animals and man may be contaminated by radionuclides from the air (gases, aerosols, dust) by inhalation or deposition on the skin, or by uptake of water and via the food chain by digestion. Animals may also be contaminated by ingestion of contaminated soil particles. 

Dimethoate is a systemic and contact insecticide-acaricide used on a range of insects including mites, flies, aphids, and planthoppers. Dimethoate is used very commonly in livestock for the control of botflies and mites. Formulations include aerosols, dusts, granules, and emulsifiable concentrates. 

Dermal exposure is the most common exposure pathway. Piperonyl butoxide is available as an aerosol, dust, emulsion, and solution. 

Particles are defined as aerosols (dust) when they are smaller than about 200 pm and larger than 0.01 pm. Smaller particles have the characteristics of a gas, and larger particles are too heavy to stay suspended and will not be inhaled. Inhalable particles which can reach the pharynx have a maximum size of 200 pm, particulate matter which is smaller than 10 pm can reach the larynx and the thorax, and respirable particles can go as far as the alveoh in the lungs (e.g. asbestos fibres) [47]. Particles with a diameter between 2 and 5 pm can precipitate in the alveoh even smaller particles are exhaled again. Air sample analysis indicates that up to 99% (by count) of particles present in the atmosphere are 1 pm or less in size [48]. 

As with lead arsenate, the broad conclusions that Neal drew from his DDT inhalation tests could be supported only by a selective reading of his data. The experiments showed that DDT aerosols often killed mice, but did little harm to dogs or monkeys. Two human beings exposed to DDT in the same form showed no evidence of poisoning. Neal s report, issued in September 1943, declared that DDT could be used safely as aerosol, dust, or mist spraying was approved that same month.19... 

The first group consists of solid particles of inorganic and also liquid droplets (e.g. fog) all of which could be in the form of aerosols. Dust is a stable colloidal system containing more large particles than smokes and fogs. The concentra-... 

The ability of the stone-colonizing microflora to cover and even penetrate material surface layers by the excretion of organic extracellular polymeric substances (EPS) leads to the formation of complex slimes, or biofilms, in which the microbial cells are embedded. Phototrophic organisms usually initiate colonisation by establishing a visible, nutrient-rich biofilm on new stone from which they can penetrate the material below to seek protection from high light intensities or desiccation. Stone EPS trap aerosols, dust and nutrients, minerals,... 

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