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Since the first outbreak of Legionnaires Disease in 1976, the subject of how illness can spread through a building’s heating, ventilation, and air conditioning (HVAC) system has been well studied and documented. Most of us have also experienced the phenomena as a flu bug infects an entire department or closes our kids’ school. But there are more problems caused by poor indoor air quality than just diagnosable illnesses.
According to the Indoor Environment Group of the Lawrence Berkeley National Laboratory (LBNL), IAQ is also affecting our productivity and performance even when we are aren’t actually “sick.” In its Indoor Air Quality Scientific Findings Resource Bank (IAQ-SFRB), which is being developed with funding support from the U.S. Environmental Protection Agency (EPA), the LBNL reveals how recent research is showing that the benefits of improved workplace IAQ are considerable for both workers and business.
One of the primary subjects of IAQ research is that of ventilation, defined as “the supply of outdoor air to a building.” In studies on “ventilation rates and office work performance (speed and accuracy),” higher ventilation rates translated directly to improved performance. “For initial ventilation rates between 14 and 30 cfm per person, the average performance increases by approximately 0.8% per 10 cfm per person increase in ventilation rate. At higher ventilation rates, the average performance increase is smaller, approximately 0.3% per 10 cfm per person increase in ventilation rate.”
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Similarly, studies performed on ventilation rates and worker absence showed even more positive results. One large office study of 40 offices was performed over a full-year period and showed that “a 35% decrease in short-term absence was associated with a doubling of ventilation rate from 25 to 50 cfm per person, corresponding to a 1.4% decrease in absence per 1 cfm per person increase in ventilation rate.” Although the LBNL says research into ventilation and correlated absences is very limited, available data “suggest that modest decreases in absence rates could be obtained by increasing building ventilation rates.”
Another research subject is air temperature, or “thermal comfort.” Studies show that performance is best when temperatures are maintained at “approximately 71°F or 72°F,” with decreases in performance averaging “0.3% to 0.4% per each 1°F change in temperature” above or below the optimum range. However, some studies have also shown that temperature increases that improve thermal comfort may also increase performance and productivity and that the overall impact of temperature and thermal comfort “may depend on the type of work and the level of the workers’ motivation.”
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The impact of removing specific indoor pollutant sources also has positive effects on performance. Studies in this area have shown “approximately 4% to 16% increases in the performance (speed or accuracy) of selected office work tasks [e.g., typing, addition errors (in one study), speed of call center work] when indoor pollutant sources were removed, while performance of other tasks (e.g., proof-reading, creative thinking) was not significantly affected by source removal.”
While these easily quantifiable aspects provide fairly definitive guidelines, research has also found that a more subjective parameter, workers’ perception of improved IAQ, can also have a positive influence on performance. According to the LBNL, “Better perceived indoor air quality is correlated with improvements in office work tasks, with approximately a 1% increase in task performance per each 10% decrease in the percentage of occupants dissatisfied with indoor air quality.” Whether poor IAQ perception negatively affects performance is not known “because the same indoor environmental conditions affect both performance and perceived air quality.”