Indoor Dust

For the general population, the oral route of exposure has been considered the major route, including inhalation of air (indoors and outdoors), ingestion of food, incidental ingestion of soil, and ingestion of dust (indoors), as well as direct contact with products that contain phthalates. Some studies suggested [17, 18] that food represents the most important source of exposure to DMP, DEP, DBP, butyl benzyl phthalate (BBP), and DEHP. A few studies showed that air inhalation could be also an important route of exposure [19-21], while others did not find any significant correlation between urinary levels in children and home dust measurements of phthalates [22]. 

In addition, other routes of human exposure are less studied, and exposure through dust (indoor and outdoor) and inhalation is necessary, and for example, the bioavailability of the current compounds from dust is unknown. 

VVOCs, (b.p. <0 to 50-100°C) and VOCs, (b.p. 50-100 to 240-260 °C) are transitory and predominantly found in air. Organic compounds of lower volatility, that is, SVOCs (b.p. 240-260 to 380-400°C) are present in air as well as in dust, whereas POM (b.p. >380°C) is part of the dust indoors. Analyses of SVOCs in indoor air and house dust are a measure of indoor contamination but may also provide valuable information for the assessment of human indoor exposure. 

A normal enclosure is meant for a reasonably clean atmosphere and a relative humidity not more than 50% for LT and 95% for FIT indoor enclosures. Where the atmosphere is laden with fumes or steam, saline or oil vapours, heat and humidity, excessive dust and water or contaminated with explosive and fire hazardous gases, vapours or volatile liquids (Section 7.11) a special enclosure with a higher degree of protection is required as in lEC 60529 or lEC 60079-14. For non-hazardous areas, the enclosure can be generally one of those discussed in Tables 1. 10 and 1. 11, and when required can be provided with special treatment to the metallic surfaces. For hazardous areas, however, special enclosures will be essential as discussed in Section 7.11. 

In such conditions, it is important that adequate care is taken to construct the bus enclosure lo weather the outdoor conditions such as by providing a canopy on the top and special paint treatment on the outdoor part. It is also recommended to seal off the indoor from the outdoor part to prevent the eflecl of rainwater, dust and temperature and other weather conditions on the indoor part. This can be achieved by providing seal-off bushings, one on... 

Indoor air quality complaints can arise from inadequate housekeeping that fails to remove dust and other dirt. On the other hand, cleaning materials themselves produce odors and emit a variety of chemicals. As they work throughout a building, cleaning staff or contractors may be the first to recognize and respond to potential lAQ problems. 

Outdoor inhalation exposure is mainly due to traffic, energy production, heating, and natural factors such as pollen and mineral dusts. These outdoor sources of pollution also affect indoor air quality. The indoor concentration is typically 20-70% of the corresponding outdoor concentration. Occasionally the indoor concentrations of an external pollutant (especially radon) may even exceed the concentrations outdoors. ... 

Air contaminants Aerosols, gases, vapors or dusts which may cause adverse effects if discharged into the indoor or outdoor atmosphere. 

Emission The undesirable liberation of a dust, gas, or vapor from a process, either indoors or outdoors. 

MMT, monomethyltin DMT, dimethyltin MBT, monobutyltin DBT, dibutyltin TBT, tributyltin MOT, monooctyltin DOT, dioctyltin Exposure via house dust (which has been measured as containing organotins) was also considered it is likely that inhalation exposure indoors includes house dust, which picks up leached organotins from vinyl flooring. 

In areas of agricultural methyl parathion usage, both outdoor and indoor air levels of methyl parathion of approximately 12 ng/m have been measured, and household dust was found to contain 21 ppb of methyl parathion. Outdoor and indoor air concentrations of methyl parathion as high as 0.71 and 9.4 pg/m, respectively, have been measured at the homes of individuals employed as pesticide formulators. 

A. Fox and R. M. T. Rosario, Quantification of muramic acid, a marker for bacterial peptidoglycan in dust collected from hospital and home air-conditioning filters using gas-chromatography mass spectrometry. Indoor Air-Intemat. J. Air Quality Cl. 4 239 (1994). 

Reduce indoor humidity to less than 50% if possible House dust mites... 

Purification of indoor air (dust and water-soluble gases such as CO2 and ammonia). 

For each category of land or water body use, one may envision a simplified scenario. In each scenario, only those activities most likely to lead to toxic exposures are considered. For example, In the Industrial scenario, Indoor workers would not be exposed to levels of dust bearing high concentrations of soli contaminants outdoor workers who stir up dry soli with heavy machinery, however, could expect to Inhale contaminant-laden dust. A scenario could Involve more than one exposure pathway. Thus, the Industrial worker might drink water from a contaminated well, In addition to breathing contaminated dust these exposures might represent not only different pathways but different sources. 

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