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Eastern Washington State School District – Intervention - Indoor Air Quality Crisis

Plus Manufacturing Inc.

June 19, 2013
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plus-p1.jpgAn Eastern Washington State school district undertook an indoor environmental assessment, study, and intervention — by Indoor Air Quality (IAQ) consultant, Dr. Miles Athey — to protect and enhance the learning environment within the district’s elementary schools.

After investigating occupant complaints and testing many IAQ parameters, Dr. Miles Athey concluded two factors were the most frequent sources of the IAQ problems: ventilation and carpets.


The ventilation issues were largely remedied with several adjustments: 1) spacers were added to close off gaps in the HVAC filter brackets, eliminating the passage of unfiltered air into rooms, 2) an array of different kinds of filters (including filtration of particles as small as 1 micron, drop-in HEPA filters for supply grilles, and carbon filters for odors) were adopted throughout the district, each designed to prevent specific air quality problems, and 3) air dampers are routinely recalibrated to coincide with the district’s computerized digital control system helping to ensure sufficient quantities of fresh outdoor air are being supplied to each room.


An inconsistent cleaning program along with material, equipment and other deficiencies had apparently contributed to a significant buildup of soap residue on and between carpet fibers in the district’s elementary schools. This residue-particle loading in carpet was exacerbated by factors such as inadequately filtered outside air through HVAC systems, outside contaminants tracked in on shoes, improper products to clean carpets, and insufficient vacuuming and hot water extraction of carpets, thus increasing respirable airborne particulates.

Measuring Particulates - Equipment and Methodology plus-p2.jpg

A MetOne laser particle counter was used to measure classroom particulate counts for particle sizes of 10, 7, 2.5 and 1 microns in diameter at carpet level in both the ambient (undisturbed) state and the aggressive (disturbed) state for 3 minutes. The aggressive sampling consisted of beating a square meter of the carpet surrounding the particle counter for the first 20 seconds of the 3 minute sampling period. This forces particulates to dislodge from the carpet fibers and become airborne.

In most cases, the ambient levels were well below the EPA’s — then current — unhealthy Air Quality Index thresholds and were comparable with outside particulate levels. However, most of the aggressive samples were substantially higher indicating that the carpets were continually over-loading on particulates and thus were not being efficiently vacuumed or extracted by cleaning procedures. While the EPA’s Air Quality Index had cautionary statements for particulates of 2.5 and 10 microns in diameter at levels of 40 and 150 micrograms per cubic meter (ug/m3), respectively, these levels were considered to be more appropriate criteria for adult and industrial applications. The California Air Resources Board, as a result of that State’s Children’s Environmental Health Protection Act, had established more stringent criteria for children. These levels were adopted for the district’s IAQ program standards: 24-hour averages of 12 ug/m3 for PM 2.5 and 50 ug/m3 for PM 10.

Baseline Measurements

The initial baseline particulate measurements were taken in carpeted classrooms of several of the district’s elementary schools while school was in session February-March. These rooms had been occupied since September of the previous year and had been vacuumed daily.

plus-p3.jpgThese data indicated that significant quantities of particulate matter had loaded into the carpets over time and the cleaning procedures were not getting the carpets as clean as desired.

Based on the data, the district began to investigate its carpet cleaning procedures, and to search for a more efficient and effective cleaning process.

Dr. Athey speculated the extraction carpet cleaners previously and routinely used by the custodial staff were leaving solvents and soapy residues that the extraction process was not able to remove without using some other cleaning compound.

Another Washington State School District recommended Procyon — manufactured by Spokane based Plus Manufacturing, Inc. — as a means to break up the particulate-trapping residue.

Students in one classroom were relocated and a “deep cleaning” program was begun on this carpet. Procyon was applied to the carpet. After testing for particulate counts before and after the application, it was inferred that this product was able to chemically or otherwise separate entrapped particulates in the carpet from the fibers and backing without damaging the material or leaving resides, something other carpet cleaning products used were apparently unable to accomplish.

Carpeting was then deep cleaned using Procyon throughout the district. The same aggressive particle sampling procedure referenced above was used for measuring particulate loading in carpets, before and after the cleaning, in five classrooms.

Summary Results

The greatest improvement was L4; PM10=69.9 ug/l before, 3.2 ug/l after, a 2184% improvement. The least improvement was P4; PM10=81 ug/l before, 8.4 ug/l after, a 964% improvement. For all five rooms sampled, the average percentages of improvement by particle size were: PM10=1582%, PM7=1620%, PM2.5=1737%, and PM1=326%.

Research Addendum Notes: The major apparent advantage of using Procyon for carpet care is that its active ingredients are inorganic. Other carpet cleaning products often use organic chemicals (solvents) which leave residues within the fibers. These residues actually increase the attraction and bonding of additional particulates into the carpet fibers. When mixed properly, the intervention solution forms a mild (degreasing) liquid that effectively dissolves bound organic particulates, releasing them from carpet fibers and backing without damaging the integrity or color of the carpet. The intervention is also non-toxic making it environmentally preferable for chemically sensitive individuals.

This content was provided by Plus Manufacturing Inc. as part of a paid advertisement.

For more information, please contact Plus directly at 1-800-PROCYON (776-2966) or

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