A recent article in the Journal of Allergy and Clinical Immunology cites a report indicating that buildings seeking LEED Certification, (buildings that are registered to become LEED Certified) are susceptible to spikes in fine, airborne particulates and may underperform in an indoor air quality test.
The report’s findings were presented at the American Academy of Allergy, Asthma, and Immunology annual meeting. These findings suggest that LEED Certified buildings may not be performing to their own standards and that LEED Certification is not necessarily indicative of a relative improvement, when compared to non-LEED Certified buildings, in indoor air quality (IAQ).
Except under certain workplace standards, indoor air pollution is not regulated in the United States.
LEED, which stands for Leadership in Energy and Environmental Design, is the leading green building certification program in the United States and measures the performance of green buildings across a series of categories including site sustainability, water efficiency, energy and atmosphere, environmental quality, building materials and resources. LEED uses its own standards to determine acceptable IAQ levels. LEED’s standards exceed those set in place by the Environmental Protection Agency (EPA).
Fine particulates are defined as particles 10 microns or less (PM10). The limit for exposure to fine particulates is a four-hour average of 50 micrograms per cubic meter (mcg/m3). The current U.S. EPA standard for outdoor particulate pollution is a 24-hour average of 150 mcg/m3.
Air was sampled in 142 new buildings seeking LEED certification. The sampling was done post-construction and pre-occupancy, which is recommended under the LEED certification program. The four-hour averages were within the LEED limit with a range of 10 to 20 mcg/m3.
However, the results were poorer when the investigators simulated the effects of human activity by running a vacuum cleaner in the buildings, a typical occurrence in commercial properties. The PM10 readings spiked to as high as 60 mcg/m3 and even larger surges were seen when indoor sampling coincided with nearby construction activity. The indoor PM10 readings rose to 200 mcg/m3 for a period of 15 minutes, and then dropped to less than 30 mcg/m3 at the end of the workday. The researchers went on to study occupied schools, apartments, and offices. The team found that the PM10 levels increased well beyond the LEED limit when people were inside doing normal activities.
In support of LEED buildings, researchers found that buildings that fail to receive LEED certification tested much higher for PM10s. This suggests that the LEED program does help reduce indoor air pollution. The study did not measure levels of PM2.5 (particles smaller than 2.5 microns). The LEED standards do not set limits for these ultrafine particles, which may be considered more dangerous than larger particles.
Click here to read the article in the Journal of Allergy and Clinical Immunology by E. Horner, P. Fritz, M. Califano and N. Sanders