Lead-containing aerosols

Centrifugation and blending of products can lead to aerosol formation and containment of such activities to prevent transfer of live microorganisms is necessary. 

The relationship between air-lead and blood-lead in the occupational setting will also vary as a function of the particle-size distribution and chemical speciation of the lead contained within occupational aerosols [25]. The uptake of inhaled lead varies as a function of the area of the respiratory tract in which it deposits. Deposition patterns within the lung, in turn, will vary as a function of particle size. Very fine... 

Personal care products that are potential indoor sources of elements include home remedies, underarm antiperspirants, and cosmetics. Zinc oxide and titanium oxide are used in many commercial sunscreen products, and zinc oxide (as calamine) has long been recognized for its healing properties (Lansdovm and Taylor 1997). Aerosolized aluminum chlorohydrate, a common antiper-spirant formulation, is one of many potential indoor sources of Al (Fishbein, 1991). Sainio etal., 2000) determined Ni, Pb, Co, As, and Cr concentrations in commercial eyeshadows, and found that 75% of the colors contained more than 5 pg g of at least one of the elements. Lead-containing remedies and cosmetics used by some Middle Eastern and Asian communities are listed by ATSDR (2000). Two Mexican folk remedies which contain Pb are azarcon and greta, which are used to treat empacho, which is a colic-like illness (ATSDR, 2000). 

Although lead pollution effectively began early in the history of mankind, the human input of this metal to the environment increased sharply in the twentieth eentury (Fergusson, 1990). For example, the burning of lead-supplemented fuels has caused the release into the atmosphere of huge quantities of lead-containing particles and aerosols (and their subsequent wet and dry deposition in waters and soils). 

Machining, sanding, drilling, or other mechanical disruptions of materials containing nanoparticles can potentially lead to aerosolization of nanomaterials. 

In addition, even where foaming is not a specific problem in a boiler, carryover may occur, especially in lower pressure boilers with very high TDS (i.e., over 10,000 to 15,000 ppm TDS) because of the collapse of surface bubbles. This leads to BW aerosol generation and entrainment of the spray in steam. Under these circumstances, antifoam agents such as polyamides are useful in preventing these entrainment problems. Furthermore, the antifoaming action of polyamides is often enhanced by protective colloid materials such as tannins, and consequently, formulations containing polyamide emulsions in an alkaline tannin base are available. 

Examples of such procedures are making dilutions (not all components of the mixture may be equally soluble or miscible with the vehicle) and generating either vapors or respirable aerosols (not all the components may have equivalent volatility or surface tension, leading to a test atmosphere that contains only a portion of the components of the mixture). 

Metals Metals are used as collapsible tubes and in aerosol containers. The most common metals in use are tin, aluminum, and lead. Tin is the most expensive, while lead is the cheapest. Laminates of tin-coated lead provide the appearance and oxidation resistance of straight tin at lower prices [89]. Tin is the most chemically inert of all collapsible tube metals. It offers a good appearance and compatibility with a wide range of products. Aluminum tubes provide the attractiveness of tin at relatively lower cost. Lead has the lowest cost of all tube metals and is widely used for nonfood products such as adhesives. However, with internal linings, lead tubes are used for such products as fluoride toothpaste. If the product is not compatible with bare metal, the interior can be flushed with wax-type formulations or with resin solutions. 

Several groups have investigated the effect of surfactants on emitted droplet size. In the early work performed by Polli et al., the surfactant sorbitan trioleate decreased the MM AD of the CFC dexamethasone suspension when added to the formulation (52). A suspension of terbutaline in a CFC system containing sorbitan trioleate surfactant was shown to have little change in emitted particle size when either 2.8 or 14mg/mL of surfactant was added (53). Interestingly, the surfactant had a significant effect on the obscuration (droplet concentration) of the laser diffraction instrument used to determine particle size. Surfactants may lead to an increase in MMAD due to decreased evaporation rates from aerosol droplets. This may occur because of their tendency to associate at the air liquid interface (54). 

---