Exposure particulate

Characterization of the Composition of Personal, Indoor, and Outdoor Particulate Exposure... 

The people who are most at risk for health problems from particulate exposure are those who already have some form of respiratory disorder or heart disease, the elderly, and children. Such problems begin to appear when the ambient concentration of pollutants reaches about 40 pg/m for PM25 particulates and about 150 pg/m for PM particulates. Such concentrations are observed during dust storms, along dusty unpaved roads, and in areas with high levels of motor vehicle traffic, for instance. Increasing concentrations of both PM2 5 and PMj particulates result in more serious health problems, including asthma, bronchitis, emphysema, and cardiac problems. 

Wegman, D.H., E.A. Eisen, X. Hu, S.R. Woskie, R.G. Smith, and D.H. Garabrant. 1994. Acute and chronic respiratory effects of sodium borate particulate exposures. Environ Health Perspec. 102(Suppl. 7) 119-128. 

Di(2-ethylhexyl) phthalate has been shown to account for 69 and 52% of the total amount of phthalates adsorbed to sedimented dust and particulate matter, respectively, in a number of Oslo dwellings. It was found at levels of 11-210 pg/100 mg [110-2100mg/kg] sedimented dust in 38 dwellings and at levels of 24-94 pg/100 mg [240-940 mg/kg] suspended particulate matter (mean SD, 60 30) in six dwellings. It was suggested that suspended particulate exposure to di(2-ethylhexyl) phthalate is one- to three-fold higher than the estimated vapour phase exposure (0ie et al., 1997). 

Eisen et al (1994) USA Nested case-control of laryngeal cancer 108 fatal and incident cases 538 controls (study base Eisen et al., 1992 cohort) 1941-84 Cumulative exposure to straight and soluble types of metalworking fluid and metalworking fluid particulate exposure during grinding duration of exposure to metalworking fluid and other components. 

Occupational exposure to chromium(VI) primarily as mist/aerosol can result in respiratory effects. Animal studies have reported respiratory effects following exposure to chromium(VI) or chromium(III) mists and particulates. Exposure to chromium in ambient air is mainly to chromium(III) adhered to dust particles (see Section 5.4.1). The possibility that inhalation exposure to chromium in the environment, from industrial sources, or at hazardous waste sites could result in respiratory effects cannot be ruled out. 

RDDR is a multiplicative factor used to adjust an observed inhalation particulate exposure concentration of an animal to the predicted inhalation particulate exposure concentration for a human based on a MMAD of 0.28 pm and a geometric standard deviation of 1.63, lung effects (TH or thoracic region) RDDR calculated to be 2.1576 using Table H-l (EPA, 1990—older version of inhalation dosimetry methodology used to calculate RDDR because MMAD <0.5 pm, so cannot use the EPA, 1994 program). 

A suitably sized solution preparation system similar to that mentioned under the previous sections can be used to provide material for bulk freeze drying. (Since product solutions can be sterile-filtered directly into the final container, microbial and particulate exposure will be minimized.) The sterile solution is subdivided into trays and placed into a sterilized freeze dryer. Aseptic transfer of sterile product in trays to the freeze dryer must be validated. After tray drying, the sterile product is aseptically transferred through a mill into suitably designed sterile containers. The preparation of sterile bulk material is usually reserved for those cases where the product cannot be isolated by more common and relatively less expensive crystallization methods. Due to recent advances in this field, a freeze drying process should be considered as a viable option. ... 

The vast majority of dollar-valued benefits from air pollution abatement arise from the impact of airborne particulates (PM2 5) on premature mortality. A 1997 EPA study reports that of the estimated 22.2 trillion worth of benefits derived from the Clean Air Act of 1970, reductions in particulate-related mortality contributed more than 20 trillion. We use a spatially-detailed air pollution dispersion model (the Source-Receptor Matrix) to evaluate the impact of SO2 emission reductions from each plant on county-level concentrations of particulates during Phase I of Title IV. Using existing evidence on the connection between particulate exposures and mortality, we translate the reductions in secondary particulate concentrations in each county in the United States into the dollar benefits from reductions in premature mortality. 

Chay and Greenstone (2003a, 2003b) examine the effect of particulate exposures on infant mortality, and obtain impacts of a similar magnitude, measured in terms of increased mortality rates. 

Fakhri AA, Ilic LM, Wellenius GA et al (2009) Autonomic effects of controlled fine particulate exposure in young healthy adults effect modification by ozone. Environ Health Perspect 117 1287-1292... 

The Nurses Health Study (Puett et al. 2008) examined the association of chronic particulate exposures with all-cause mortality, incident nonfatal myocardial infarction, and fatal coronary heart disease (CHD) in a prospective cohort of 66,250 women from the Nurses Health Study in north-eastern US metropolitan areas. In an age- and season-of-the-year-adjusted models, 10 pg/m increases in 12-month average exposures to PMio were associated with increased all-cause mortality (RR 1.16, 95% Cl 1.05-1.28) and fatal CHD (1.43, 95% Cl 1.10-1.86). 

Regulatory DOT nonregulated SARA 311/313 nonreportable EU, Canada DSL, Australia, Japan, Korea listed Properties Whitish micronized powd. 9 p avg. particle size essentially odorless negligible sol. in water dens. 0.94 g/cc drop pt. (Mettler) 113 C acid no. nil flash pt. 240 C hardness 1.0 dmm = 100% act. Toxicology ACGIH TLV/TWA 3 mg/m respirable particulate exposure to wax fumes may cause irritation may be mild skin irritation molten material will cause thermal skin burns dust/fumes from molten material may be irritating to eyes, respiratory tract TSCA listed... 

Kelleher PC, Martyny JW, Mroz MM, et al. BerylUum particulate exposure and disease relations in a beryllium machining plant. J Occup Environ Med 2001 43(3) 238-249. 

Mahar S. Particulate exposures resulting from the investigation and remediation of a crash site of an aircraft containing carbon composites. Am Ind Hyg Assoc J 1990 51 459-461. 

A variety of hypotheses relating particle properties to biological effects have been proposed to explain the pulmonary response to various forms of particles. Particle size, surface area, surface composition, and crystal structure have been proposed as key properties influencing particle-tissue interactions. Clearance, and impairment of clearance have also been implicated as mechanistic factors determining the outcome of particulate exposure. Although these are important issues that must be recognized, they are outside the scope of the current chapter. 

A central hypothesis derived from this data is as follows Ambient air particles are complex mixtures with intrinsic toxicity. In concert with preexisting inflammation, particulate exposure results in stimulation of lung receptors and immune cells, release of reactive oxygen species (ROS), and induction of pro-inflammatoiy mediators that lead to local and systemic effects, which ultimately account for the epidemiological associations between adverse health effects and particulate air pollution. Hypothetical mechanistic pathways by which inhalation of ambient particles in urban air may lead to morbidity and mortality are outlined in Figure 1. 

For both adults and children, chronic cough and bronchitis are associated with increased particulate air pollution. However, wheeze and asthma were associated with chronic particulate exposures only among adults, but not in studies of children. This may reflect the very different charaeteristies of asthmatic symptoms and disease in ehildren and the elderly. 

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