Indoor Air Quality / Volatile Organic Compounds

What is Indoor Air Quality and Why is it Important?

The U.S. Environmental Protection Agency defines indoor air quality as being “the air quality within or around a building, as it relates to health and comfort of building occupants”.1Indoor air quality is dependent upon air circulation, concentration levels of pollutants, and ventilation.

Concentration levels of Volatile Organic Compounds (VOCs) emitted from liquids found in everyday household items can cause immediate-health problems for occupants and some can create long-term, irreparable health difficulties. VOCs are chemicals that which can off-gas (evaporate from liquid to gas phase) at room temperature.

Due to the nature of these symptoms it can be difficult to pinpoint the source to poor indoor air quality.

  • Immediate symptoms experienced by occupants are similar to that of a common cold: irritation to the eyes, nose and throat, headaches, dizziness, and fatigue.
  • Long-term adverse health effects can be more serious, and can even show up years after the exposure: respiratory diseases, heart disease, and cancer.

Factors that affect the severity of the illness in people include: the age (children and the elderly being the most vulnerable), preexisting medical conditions (i.e. asthma), exposure length, concentration level of the chemical, and repeated exposure.1

Background on the Importance of Indoor Air Quality

Building weatherization was the earliest form of improving energy efficiency in response to the rising energy costs. In the late 1970’s, in Sweden, the early form of the blower-door test was invented. This test is used to depressurize a building to determine building leakage and help to determine areas of the building air tightness can be improved as a part of retrofitting buildings for weatherization.

Building envelopes were sealed to the exterior elements that may cause unwanted temperature fluctuations in the indoor environment such as heat loss in winter conditions, which in turn would make the occupants turn the heat up, and heat gain in summer conditions, which would make the occupants turn the air conditioning up. Air tightness done wrong, however, leads to a build-up of contaminants in the indoor environment, as discovered in the 1980’s. Mold and toxic materials from everyday items and building materials began to make occupants sick.2

The Sick Building Syndrome states that poor indoor air quality is related to adverse health impacts for the inhabitants. This lead to the development of green building rating systems, such as Leadership in Energy and Environmental Design (LEED). LEED has helped to refocus the entire building industry, from renovations of existing buildings to new developments. LEED has improved the way buildings are designed which has enhanced the indoor environmental quality for occupants.

Hardwood Floors Effect on Indoor Air Quality

Along with improving building ventilation and air circulation, manufacturers of building materials had to improve their chemical ingredients as to reduce health impacts from emissions of harmful chemicals from off-gassing of newly produced products. Per the U.S. Environmental Protection Agency, chemical off-gassing from materials can be 2-5 times higher indoors than ambient concentration levels of outdoor levels, sometimes even as high as 1,000 times the outdoor concertation levels.1

During the wet application process, wood floors off-gas VOCs while the floor finish cures. Varnishes and waxes all contain organic solvents. Installing prefinished hardwood floors, the type of finish used (wax, water, polyurethane based), and the ventilation in the space can greatly improve the air quality in the space of the new hardwood floors. However, off-gassing can occur for days, weeks, months even years after the installation. It is important to pay attention to the chemical contents in the finishes being used. Some VOCs include benzene, fomaldehyde, toulene, xylene and arsenic.

Indoor Air Quality Studies

A recent study conducted by a group of experts from Harvard School of Public Health, Syracuse, Upstate Medical University, and United Technologies concluded that office workers have lower cognitive function in offices in conventional buildings which tend to have low indoor air quality. Control groups were put into two separate environments: one simulating green building indoor conditions and the other that of conventional building conditions. Everyday tasks were recorded for how well they were performed: activity level (basic, applied and focused), task orientation, crises response, information seeking, information usage, breadth of approach and strategy. The study showed office workers in green buildings had significantly better cognitive function than those in conventional buildings. The study also concluded that carbon dioxide (CO2) and VOCs caused significant cognitive deficits at levels found in conventional buildings. Increasing the ventilation of outdoor air in green buildings lowered the exposure of said indoor environmental pollutants and showed higher cognitive function.3


1Indoor Air Quality. c2017. Washington (D.C.): United States Environmental Protection Agency ; [accessed 2017 Jan 25].

2 Santamouris M, Wouters P. Building Ventilation: The State of the Art. London (UK): Earthscan; 2006.

3 Allen JG, MacNaughton P, Satish U, Santanam S, Vallarino J, Spengler JD. 2016. Associations of cognitive function scores with carbon dioxide, ventilation, and volatile organic compound exposures in office workers: a controlled exposure study of green and conventional office environments. Environ Health Perspect 124:805–812;

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