VOC

Volatile organic compounds (VOCs) are emitted as gases from certain solids or liquids.  VOCs include a variety of chemicals, some of which may have short- and long-term adverse health effects.

Concentrations of many VOCs are consistently higher indoors than outdoors. VOCs are emitted by a wide array of products numbering in the thousands. Examples include: paints and lacquers, paint strippers, cleaning supplies, pesticides, building materials and furnishings, office equipment such as copiers and printers, correction fluids and carbonless copy paper, graphics and craft materials including glues and adhesives, permanent markers, and photographic solutions.

Organic chemicals are widely used as ingredients in household products. Paints, varnishes, and wax all contain organic solvents, as do many cleaning, disinfecting, cosmetic, degreasing, and hobby products. Fuels are made up of organic chemicals. All of these products can release organic compounds during usage, and, to some degree, when they are stored.

Testing emissions from building materials used indoors has become increasingly common for floor coverings, paints, and many other important indoor building materials and finishes.

Carbon Monoxide

One of the most acutely toxic indoor air contaminants is carbon monoxide (CO), a colorless, odorless gas that is a byproduct of incomplete combustion of fossil fuels.  Common sources of carbon monoxide are tobacco smoke, space heaters using fossil fuels, defective central heating furnaces and automobile exhaust.  Improvements in indoor levels of CO are systematically improving from increasing numbers of smoke-free restaurants and other legislated non-smoking buildings. By depriving the brain of oxygen, high levels of carbon monoxide can lead to nausea, unconsciousness and death.

Molds and Other Allergens

These biological chemicals can arise from a host of means, but there are two common classes:

• Moisture induced growth of mold colonies
• Natural substances released into the air such as animal dander and plant pollen. 

Moisture buildup inside buildings caused by water penetrating the building envelope or skin, from plumbing leaks, from condensation due to improper ventilation, or from ground moisture entering a building part will result in mold. When materials such as paper, wood or drywall become moist and fail to dry within 48 hours, mold mildew can propagate and release allergenic spores into the air.

In many cases, if materials have failed to dry out several days after the suspected water event, mold growth is suspected within wall cavities even if it is not immediately visible. Through a mold investigation, which may include destructive inspection, one should be able to determine the presence or absence of mold. In a situation where there is visible mold and the indoor air quality may have been compromised, mold remediation may be needed. Mold testing and inspections should be done by an independent investigator to avoid any conflict of interest and to insure accurate results; free mold testing offered by remediation companies is not recommended.

There are some varieties of mold that contain toxic compounds (mycotoxins). However, exposure to hazardous levels of mycotoxin via inhalation is not possible in most cases, as toxins are produced by the fungal body and are not at significant levels in the released spores. The primary hazard of mold growth, as it relates to indoor air quality, comes from the allergenic properties of the spore cell wall. More serious than most allergenic properties is the ability of mold to trigger episodes in persons that already have asthma, a serious respiratory disease.

Mold is always associated with moisture, and its growth can be inhibited by keeping humidity levels below 50%. Moisture problems causing mold growth can be direct such as a water leaks and/or indirect such as condensation due to humidity levels.

Radon

Radon is an invisible, radioactive atomic gas that results from the radioactive decay of radium, which may be found in rock formations beneath buildings or in certain building materials. Radon is one of the most pervasive serious hazard for indoor air, probably responsible for tens of thousands of deaths from lung cancer each year.  There are relatively simple tests for radon gas, but these tests are not commonly done.

Radon is a heavy gas and will accumulate at the floor level. Building materials can actually be a significant source of radon, but little testing is done for stone, rock or tile products brought into building sites.  Radon accumulation is greatest problem for well insulated homes. The half life for radon is 3.8 days, indicating that once the source is removed, the hazard will be greatly reduced within a few weeks.

Radon levels can be reduced by sealing concrete slab floors, basement foundations, water drainage systems, or by increasing ventilation. They are usually cost effective and can greatly reduce or even eliminate the contamination and the associated health risks.

Indoor Air Quality

Indoor air quality is a term referring to the air quality within and around buildings, especially as it relates to the health and comfort of the people inside the building.  Indoor Air Quality can be affected by:

• Microorganism contaminants such as mold and bacteria
• Gases; including, carbon monoxide, radon, volatile organic compounds
• Particulates that can causes adverse health conditions

Indoor air is more of a health hazard than outdoor air. The primary methods for improving indoor air quality are:

• Proper ventilation to dilute contaminants
• Filtration 
• Air source control 

Indoor Air Quality is determined and controlled by collecting and analyzing air samples, monitoring human exposure to pollutants, collection of samples on building surfaces and computer modelling of air flow inside buildings.