Share thisIndoor air quality, known as IAQ, and now broadened to indoor environmental quality (IEQ), became a major issue in the early 1980s. Problems developed from energy conservation measures adopted in the late 1970s that limited functioning windows and introduction of outside air into buildings. The resultant “tight” buildings and 100% recirculating heating, ventilating, and air conditioning (HVAC) systems produced myriad problems for building occupants and owners alike. What began as a few cases of tight building syndrome exploded into high profile cases of multiple chemical sensitivity and indoor mold contamination—and IAQ issues were born.
Today we are in much better shape thanks to efforts of the Environmental Protection Agency (EPA), Occupational Safety and Health Administration (OSHA), American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE), and the U.S. Green Building Council (USGBC). Both the EPA and OSHA have extensive information and guidance at their respective websites.1,2 You can learn as much as you want to know about indoor air quality, building systems, preventing problems, and troubleshooting with the comprehensive materials developed by these government agencies. And, the good news, it’s free. Non-governmental organizations like ASHRAE and USGBC have also advanced the science of indoor air quality. ASHRAE’s ventilation guide is considered by many to be the IAQ designer’s bible providing very important information on fresh outside air quantities.3 The USGBC Leadership in Energy and Environmental Design (LEED) program presents cutting edge guidance for designing and building the new generation of green buildings with focus on occupant health and indoor air quality.4
However, even with this wealth of information and today’s sophisticated HVAC systems, indoor air quality issues arise due to many different reasons—a preventative maintenance was missed, a belt broke on a crucial exhaust fan, a suite was just renovated with new furnishings and floor coverings, or a delivery truck sat parked in front of the outside air intake for a few hours. We have come across all of these issues and spent valuable time running down the cause and correcting the problems. Some transgressions are unforeseeable and unavoidable, but many can be headed off or even prevented with a minimal effort focused on routine checking of the facility’s indoor air quality.
How do we check our IAQ?
Digging through the massive volumes of indoor air quality information is daunting for most of us and too time consuming.We often deal with situations only when they become a crisis. Then we are scrambling to fix the problem or call in experts. But, having dealt with IAQ issues for the past couple of decades and poured over the guidance documents, we have developed a tool, an air testing protocol, that may help prevent many of the common indoor air quality issues.
This air testing protocol is based on EPAIAQ studies and the USGBC LEED indoor air quality commissioning requirements. It consists of a complete facility (or area of concern) survey for specific parameters and contaminates and is performed with portable instruments so data is real time and available immediately. It is quick, simple, and straightforward— and inexpensive even if consultants are hired to perform the work. (The alternative is to rent the instruments and have in-house staff take the measurements.) Best of all, the data is directly compared to existing OSHA, EPA, ASHRAE and LEED standards or recommended guidance levels and related to occupational health conditions.
Base IAQ Assessment Protocol
Begin the indoor air quality survey by taking measurements of the classic four parameters: temperature, relative humidity, carbon dioxide, and carbon monoxide. This is most easily done using a modern hand-held IAQ meter such as the TSI Q-Trak™, or equivalent, which can measure these four parameters at once. Temperature, relative humidity, and carbon dioxide are important indicators of HVAC system performance as well as occupant comfort. ASHRAE standard 62.1-2010 provides excellent guidance on these criteria. If problems pop up with these indicators it could mean the system is out of balance or the percentage of outside air is insufficient. Carbon dioxide is also dependent on occupant loading and tends to increase during the workday. If “hot spots” of accumulation or buildup are noted, first verify the proper amount of outside air, then check the supply flows and adequate distribution in the area. ASHRAE recommends that carbon dioxide levels be kept below the ambient level plus 700 ppm.3 The theoretical amount of carbon dioxide in outdoor air is around 350 ppm.