A Crash Course on Indoor Air Quality

By Jennifer Easton, Communications Associate, U.S. Green Building Council

The EPA estimates that we spend as much as 90% of our days in buildings, so it’s no surprise that buildings have a significant impact on our health and well-being. The air we breathe in our offices, schools, and homes not only has a profound effect on our health, but also on the value of our buildings, which is why indoor air quality must play a significant role in the building process.

Good Indoor Air Quality, or IAQ, ensures building occupants breathe air that’s free of both harmful contaminants and conditions associated with health issues. IAQ has an effect on the happiness and productivity of occupants, and good, clean IAQ has been linked with reduced absences and increases in productivity. At its best, good IAQ creates a healthy and enjoyable atmosphere for employees and can save building owners and managers extensive time and money by avoiding major retrofits down the road. Poor IAQ, on the other hand, can cause major added costs for building owners and managers for associated repairs and readjustments.

The U.S. Green Building Council (USGBC), in conjunction with the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) and four other building industry leaders recently released Indoor Air Quality Guide, 40 strategies for achieving healthy IAQ. A collaboration between USGBC, ASHRAE, the American Institute of Architects (AIA), the Buildings Owners and Managers Association (BOMA) International, the U.S. Environmental Protection Agency (EPA), and the Sheet Metal and Air Conditioning Contractors of North America (SMACNA), Indoor Air Quality Guide emphasizes the importance of good IAQ and its contribution to healthy green buildings.

The new guide explains an array of methods for planning and achieving good IAQ for better occupant health and higher building value. Below are a series of expanded tips, based on facts from the guide, and intended to give building owners, managers, and practitioners a crash-course in IAQ.

Begin planning for IAQ at the very beginning of the design process.

The most important tip in the Indoor Air Quality Guide is that IAQ should be accounted for at the very beginning of the development and design process, since often opportunities to accommodate IAQ into building plans are lost by the time the building’s schematic design is complete. When IAQ is left as a late addition, after the building layout and ventilation system are defined, it may be impossible to provide the desired air quality within the structure.

A variety of decisions in the building process may work against IAQ, such as selecting indoor finishes that lead to high VOC emissions or moisture problems in the building envelope. If IAQ is taken into consideration from the very beginning of the planning stages, these pitfalls can be avoided. Plus, bringing IAQ plans into the first stage of building design proves cost effective, making good IAQ easy to attain at lower or even no added cost, all the while avoiding costly retrofits in the future.

Control indoor humidity.

Indoor humidity should be a strong consideration in any building’s IAQ plan, as it affects occupant health and comfort. High humidity can bring on condensation that may spur biological contamination like mold, or lead to the degradation of materials. Conducive to dust mite populations, high humidity also contributes to allergies. Building projects should aim to reach a careful balance in humidity levels, as low humidity adversely affects occupant health by drying out mucous membranes. Additional consideration should be given to humidity control in special circumstances, including hot and humid climates, conditioned spaces with large indoor moisture sources, and spaces with unusually cold surfaces.

ASHRAE Standard 62.1 now requires that designers take certain actions to ensure healthy humidity levels in buildings, such as selecting automatic temperature controls for humidity considerations. Monitoring a building’s humidity may also prove useful in tracking the effectiveness of humidity control parameters and system performance. Since instruments measuring humidity tend to be high-cost, several inexpensive options are recommended, including water heater overflow pans, secondary condensate pans, and liquid moisture sensors in below-grade floors subject to flooding.

Limit the entry of outdoor contaminants.

Like humidity control problems, outdoor air pollutants entering a building can have adverse health effects for occupants, ranging from cardiovascular problems to aggravation of asthma. Outdoor contaminants include herbicides and pesticides, radon, contaminants carried by pests, as well as particles and gases in outdoor air. A key first step to creating a filtration plan is to investigate local outdoor air quality to determine the level of filtration required for a healthy indoor environment. The Green Book, available on the Environmental Protection Agency (EPA) Web site, http://www.epa.gov/air/oaqps/greenbk/, is a useful resource for evaluating local air quality. Using enhanced filtration and air cleaning in buildings located in areas of poor outdoor air quality ensures high quality ventilation air. It’s highly advisable to locate outdoor air intakes away from contaminant sources to ensure that incoming air from outside does not disrupt good IAQ within the building.

Select adequate building materials and furnishings.

While outdoor contaminants must be taken into consideration in order to provide good IAQ, indoor contaminants should not be overlooked. It is now easier to evaluate the chemical effects and emissions of materials and products used in building construction, finishing, and furnishing, as well as their impact on IAQ. In general, materials and furnishing should be selected for minimal emissions of harmful or irritating compounds. Using non-offensive building materials saves money by reducing the need to dilute air contaminants with costly ventilation methods. Building designers should research the cleaning methods for the low-emitting products that they select, which could be offset by high-emitting cleaning products. Emissions rates for building products and materials vary significantly over time and the emissions lifespan of a product should be factored in. For some products, chemical emissions decay rapidly, while other products may release contaminants at nearly constant rates for many months. Since the rate of emissions decay has different effects on IAQ, the rate should play into product and material selection.

For more tips on obtaining good IAQ in any building, purchase the Indoor Air Quality Guide or peruse the shortened online manual, available for free download at www.ashrae.org/iaq.

Headquartered in Washington, D.C., the U.S. Green Building Council http://www.usgbc.org is the nation’s leading coalition for the advancement of buildings that are environmentally responsible, profitable, and healthy places to live and work. Established in 1993, the Council offers various products and services to include the LEED Green Building Rating System, an annual International Green Building Conference and Exposition, membership summits, information exchange, education, and policy advocacy.

* The articles appearing in this section are written by the organizations as stated with each paper; FMLink is not responsible for the accuracy of their content. Should anyone wish to contact FMLink regarding any article, please e-mail FMLink at contact@fmlink.com. Contact information for each organization is provided inside each paper.