Organic Contaminants In House Dust

The human population is exposed to a growing number of emerging chemicals that are used in a wide variety of processes and products such as additives in plastics (e.g. plasticizers, polymer property modifiers, filler, stabilizers, surfactants, flame retardants), electronics, building materials and health care products. Because people spend much of their time indoors such as homes, workplaces and schools[1], exposure of indoor contaminants are of great concern. Several studies have identified house dust as an important exposure media of these chemicals. Organic contaminants found in house dust, including compounds banned long time ago, are often sources of exposure for the human population. House dust is a medium for semi volatile organic compounds

The pollutants can settled themselves much better in dust than other sink materials. Because dust particles are very small in size, have a much greater surface area-to-volume ratio, can settle on source or non-source surfaces, and can be re-suspended[zz]. The transport from indoor air pollutants from different sources to settled house dust can occur via several ways. Such as volatilization from the source with subsequent partitioning to dust (evaporation), abrasion of the treated product, transferring microscopic fibers or particles to the dust and direct uptake to dust via contact between source and dust.

There are many different sources of indoor contaminants. One of the major sources are chemicals emitted from building materials. As example, the products of composite-wood such as plywood, particleboard, oriented strand board and medium density fiberboard each emits a mix of aldehydes and terpenoids. The use of PVC pipes and wire/cable insulation in the indoor environment has increased during the past 50 years. This contains organotin compounds as stabilizers, which can migrate into indoor environment, and plasticizers, primarily phthalate esters which can emitted from the

These include electronic equipment, appliances, furnishing, paints, flooring, cleaning products, carpeting and clothing. Electronic equipment products are growing in size and number of components, which result in increased emissions of plasticizers and flame-retardants. Also carpeting, furnishing and clothing are treated with flame-retardants which emitted into the indoor environment. Appliances, a microwave as example is typically unvented and emits cooking fumes such as nitrogen dioxide into the indoor environment[7]. Paints contains texanol as coalescing agent. Texanol is semi volatile and continue to be emitted from painted surfaces for months after application. Nowadays there is a new trend towards greener cleaning agents. The cleaning products are created with terpenoid based solvents which reacts at relatively fast rates with ozone. This resulted in production of ozone-derived pollutants such as formaldehyde and secondary organic aerosols.[6]

The last important source of indoor contaminants is caused by personal habits. Smoking is the major exposure pathway in indoor health risks of environmental tobacco smoke (ETS) [6]. ETS contains over 4000 chemicals with more than 60 known carcinogens. The biggest carcinogens present in ETS are the PAHs[xx]. Also the use of air conditioning results in less outdoor-to-indoor transport of ozone, nitrogen dioxide and submicron