Indoor exposure potential, applicator

Fenske, R.A., K.G. Black, K.P. Elkner, C.L. Lee, M.M. Methner and R. Soto (1990). Potential exposure and health risks of infants following indoor residential pesticide applications. Am. J. Public Health, 80, 689-693. 

Indoor exposure assessments can be more complex than outdoor assessments. The indoor assessments are often complicated by the fact that pesticide application methods and their placement within the indoor environments are very diverse and include, for example, crack and crevice treatment, carpet treatment, room loggers, moth repellents, residual termiticides, disinfectants and pet products. This diversity also means that potential human contact with the residues may range from a low probability (crack and crevice treatment) to a higher probability (indoor broadcast treatment such as an indoor total release logger) because of the nature of the application and the variability in activities that may bring individuals in contact with treated areas. Furthermore, the varied characteristics of the source (e.g. formulation type, application methods, room of application and duration of emission) and the indoor residential environment (e.g. room size, air exchange rates, temperature and types of surfaces, such as carpet, upholstery, vinyl, etc.) significantly influence exposure pofenfial. 

Indoor Exposure. Products to be used indoors (houses, institutions, greenhouses, etc.), may have potential exposure (inhalation, dermal, and ingestion) hazards both during the application and upon reentry. An appropriate ventilation period may be needed to protect residents, inhabitants, or workers in the treated area from inhalation of hazardous chemicals as well as from contacting residues on carpets, countertops, etc. A study outline has been developed and used by the CDFA for studies it conducts to acquire needed data this is available upon request for others to use to plan their studies. 

Epoxy resins are the most commonly used thermosets, used for durable and inert coatings, in laminates and various composite applications, as well as an adhesive. Epoxies have low vapour pressures, so the potential for respiratory exposure is very low, and hence they do not pose health hazard indoors. The potential for dermal (contact) exposure is, however, much greater than respiratory exposure, which should not be a problem at all for a finished construction indoors. It is a reaction product of epichlorohydrin and BPA, which are not carcinogenic or a ECD agent. 

In addition to its presence in the ambient atmosphere, diazinon also has been monitored in both outdoor and indoor air associated with its use in a variety of domestic, commercial, and occupational exposure situations. Exposure to diazinon from its use in lawn and home garden applications was evaluated by Davis et al. (1983). Diazinon was mixed with water and sprayed using compressed air sprayers or hose-end sprayers, and potential respiratory and dermal exposures were estimated from residues collected from respirator filters, body pads, and hand rinsings. These authors reported mean respiratory exposures of 1.9,... 

Exposure to VOCs in public beauty shops can also be high. Many cosmetic products contain VOCs such as 2-phenoxyethanol, 2-butanone, acetone, terpenes, 2-hydroxy-4-methoxy-benzophenone or phenylmethanol. In particular, hair sprays are potential sources of indoor pollutants. To estimate VOC concentrations associated with the use of beauty products, a female subject was placed in the model room described earlier and sprayed with 16.1 g hair lacquer. Propellant gases (butane, pentane), ethanol, limonene and tripropyleneglycol (isomers) were subsequently monitored in the room. Thirty minutes after the application of this product, the highest VOC concentrations were measured for ethanol (>100pg/m3)... 

Indoor concentrations of pesticides in proximity to pesticide-treated farmland have been measured (Fenske et al., 2002). For example, it has been shown that pesticide exposure in children could potentially be increased if they live in homes in close proximity (60 m) to pesticide-treated farmland (Fenske et al., 2002). Clothing and cars of farm workers can also be a source of pesticide exposures for children. Usually, applications of insecticides and herbicides in and around the home are a more likely source for children s exposures. 

Residential risk assessment to pesticides typically involves more than one sonrce and mnitiple pathways and rontes, e.g. a given active ingredient may be nsed for multiple indoor apphcations, and in some cases, for outdoor applications. In some cases, the applications may overlap with respect to timing (calendar days). The potential co-occurrence of applications and potential exposures requires temporal product use information. Such information is rarely available. 

The typical end-use product and application method chosen as representative of the extreme-case exposure scenario must be used to attain the highest permissible rate allowed by label directions. Sampling for indoor residues should consider all potential sites where appreciable residues are expected and are accessible. For instance, dermal contact may come from exposure to the pesticide as a residue on carpets, vinyl tile, upholstery and counter tops, while airborne residue (vapor- or particle-phase) may provide the source of inhalation exposure. The measurements taken are linked specifically to the method of application. 

This study provides a means for conservatively estimating potential post-application dermal exposures to treated surfaces following the use of indoor total release foggers by using a high-contact, but reproducible activity. The procedure for estimating potential dermal exposure is based on the use of transfer factors (TFs) derived from the human volunteer dermal dosimetry and treated carpet transferable-residue measurements based on an indoor roller method (Ross et al, 1990, 1991). 

The EU-ECA-WG 13 found, however, that the TVOC measure is a suitable way of reporting exposures to VOCs indoors if it is measured in the way proposed by the group. Although many uncertainties remain with the use of a TVOC value, especially with regard to the type and quantity of potentially associated health and comfort effects, the working group felt that such use can be beneficial if the limits of application are outlined and respected. 

For maximum safety, avoid use or storage indoors. Indoor areas should have positive ventilation with at least 6 volumes of air changes per hour. Use of a fume hood in laboratories is advisable. Automatic air-monitoring equipment is advisable in indoor applications. Isolated outdoor areas provide maximum handling safety. Natural ventilation helps to dissipate leaks rapidly. Gas dispersion analysis should be performed for a specific location to determine potential geographic exposure. 

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