Assessment, Evaluation and Control of Indoor Environmental Issues

PO102 ​
​Assessment, Evaluation and Control of Indoor Environmental Issues

Monday, June 1, 2015, 10:30 AM - 12:30 PM

CS-102-01 Federal Post-Disaster Indoor Environmental Pollutants Guidance

W. Friedman, HUD, Washington, DC

Situation/Problem: Several federal agencies, including EPA, HHS (CDC and NIEHS), HUD, and DOL have issued guidance on rehabilitation and remediation techniques for homeowners. Because of their differing agency authorities, missions, technical expertise, and organizational experiences, such guidance differed from agency to agency. This became significant after Hurricane Sandy, when the public (including industrial hygienists and environmental professionals) sought guidance on how families should address indoor environmental quality issues after the disaster.

Resolution: The federal Hurricane Sandy Rebuilding Strategy established the Indoor Environmental Pollutants Work Group with the charge that FEMA, EPA, HUD, and HHS issue consolidated guidance on remediation of four indoor air pollutants: mold, lead, radon, and asbestos. The Work Group invited OSHA to join, which it did. The Work Group assembled technical experts from its agencies to review their existing guidance and guidance, recommendations and standards from other government agencies (international, federal, state and local), standards organizations, and nongovernmental organizations, to provide the basis for developing consolidated guidance documents regarding each of the four pollutants.

Results: The Work Group identified commonalities in the agencies’ guidance, and built upon them to harmonize differences on remaining subjects, reflecting state of indoor environmental quality science and engineering. For each pollutant, the Work Group developed a pair of 4-page plain-language guidance documents, one for each of two sets of target audiences: homeowners, and local community development and health groups; and contractors and consultants, with the latter documents more operational. The Work Group engaged communications and outreach professionals from its start to ensure that language and graphic styles were appropriate, and to design the guidance’s outreach plan.

Lessons Learned: 1: The different agency approaches could be harmonized, motivated by the agencies recognition that it had proved unnecessarily difficult for the users of their guidance to reconcile them in the field after a disaster. 2: The information gained from Hurricane Sandy specifically is applicable to the broader range of disasters to come. 3: Engaging communications and outreach professionals from its start increased the effectiveness of the guidance and its outreach.

SR-102-02 Assessing the Effectiveness of Air Duct Cleaning on Indoor Environmental Quality at a Large Laboratory Facility

J. Archer, US EPA, Research Triangle Park, NC; A. Imler, Eastern Research Group, Inc., Morrisville, NC

Objective: A large laboratory facility had a history of indoor environmental quality (IEQ) issues and workspace contamination because of visible particulate matter (PM) emanating from supply ductwork in offices and labs. The major source of particulate throughout the ductwork was determined to be from deterioration of metallic surfaces in the HVAC system. Because of these IEQ issues, a comprehensive duct cleaning project was initiated after other interim steps were not fully successful. To investigate the effectiveness of the duct cleaning, industrial hygiene sampling for airborne PM was conducted before and after duct cleaning.

Methods: Real-time PM mass concentration (μg/m3) and particle counts (six size bins from 0.3 to 10 μm) were measured in representative offices and labs throughout a five-floor office/lab wing. Continuous sampling was conducted over four-week periods prior to and after the duct cleaning in the same locations. Filter samples for PM2.5 were also collected at several of these sampling locations and analyzed gravimetrically with elemental analysis conducted by X-ray fluorescence. Outdoor PM levels were also simultaneously measured and controlled for in statistical analysis. Pre- and post-duct cleaning PM measurements were compared using repeated measures linear models (SAS v9.3).

Results: The predominant airborne PM indoors and outdoors was observed to be in the 0.3 µm and 0.5 µm size bins. After controlling for outdoor PM levels, particle counts at these smaller particle sizes showed statistically significant decreases (p<0.05) indoors after duct cleaning. Additionally, particle mass concentration (Total PM) showed a statistically significant decrease (p<0.05) post duct cleaning. Elemental composition of the PM indoors was not significantly different between pre- and post-duct cleaning.

Conclusions: There is little evidence in the literature documenting the effectiveness of air duct cleaning. In this study, however, the supply duct cleaning in a large laboratory facility produced positive results in terms of reducing airborne PM inside the building. Additionally, other tangible benefits resulted from the duct cleaning process including increased energy savings. There is also anecdotal evidence that duct cleaning has increased the comfort of building occupants and reduced health-related complaints that may have resulted from the PM-contaminated ductwork.

CS-102-03 Mysterious Eye Illnesses in a Commercial Kitchen

C. Haury, Golder Associates, Inc., Jacksonville, FL

Situation/Problem: Eye irritation began in a commercial kitchen with one employee reporting that he went to see his physician and was provided a diagnosis of conjunctivitis. After his first day back to work, he again experienced eye irritation and was sent home. A few days later, three employees reported eye irritation and sought medical treatment. The three employees missed a day of work and the employer suspected, as did the physicians, that an eye infection was being spread in the workplace. The worker’s compensation insurer was put on notice regarding the eye illnesses as it began to appear that there may be an occupational connection to the eye illnesses. The eye irritation improved when employees were away from work but symptoms returned when they resumed work.

Resolution: The kitchen was equipped with natural gas-fired cooking appliances and a variety of chemicals were used for sanitizing kitchen surfaces and dishes. A leak was found in the chlorine dispensing equipment for the dishwasher and repaired. Gas connections were inspected for all appliances and found to be leak-free. The HVAC system was assessed by a specialty contractor and found to be operating normally. Sources of contaminants in make-up air were investigated and no sources were found. A mold investigation did not find any mold growth or other microbial irritant. Air monitoring did not indicate airborne chlorine or formaldehyde. Eventually, all gas usage was discontinued and the dishwasher system was shut down. Even with these measures, employees continued to experienced eye irritation which was lessened with the use of goggles.

Results: The source of the exposure was finally found after investigating an electronic flying insect trap.  

Lessons Learned: Industrial hygienists must use their specialized skills and investigate all sources of exposure to provide solutions. Occupational illnesses are often difficult to associate with workplace exposure and require concerted efforts.

CS-102-04 IEQ Issues in a Newly-Constructed Laboratory Research Building

M. Brinton, Weill Cornell Medical College EHS, New York, NY

Situation/Problem: In January 2014, Weill Cornell Medical College (WCMC) began occupancy of a newly-constructed 438,000 net square foot wet-bench research laboratory building. Shortly after partial occupancy, researchers began complaining of strong “sewer-gas” odors in the building. When the construction management company was unable to identify the source, a team consisting of WCMC Environmental Health and Safety (EHS), WCMC Engineering and Maintenance, the construction manager and the design engineers was assembled to identify the source(s) and resolve the issue. 

Resolution: By reviewing the building’s mechanical systems and utilizing direct-read instrumentation (PIDs and electrochemical sensors), the odor was identified and traced to multiple sources (acid waste neutralization system and sewage ejector pits). The building mechanical systems (plumbing, HVAC and elevator) were also assessed to determine the pathways by which the odor was traveling. Final resolution required implementation of multiple administrative and engineering controls. 

Results: Levels of hydrogen sulfide gas (range of 500 - 900 parts per billion) and total volatile organic compounds (0.5 to 1.5 parts per million) were reduced in complaint spaces to a level below detection limits and the odor complaints were eliminated.

Lessons Learned: Despite intense pre-construction review of the building’s design plan by a team that included an industrial hygienist, building mechanical systems can operate in unpredicted ways due to unforeseen factors. It is therefore important to assemble a team of knowledgeable parties to address these issues, review the project throughout its many phases and attempt to identify potential IEQ issues before they arise. In addition, special attention should be given to specialized building systems and their potential relationship to other building mechanical systems.

SR-102-05 Characterizing Air Quality in Manned Habitats Using a Portable FTIR Spectrometer

O. Monje, Air Revitalization Lab, Kennedy Space Center, FL; A. Caraccio, NASA KSC, Kennedy Space Center, FL

Objective: The objective was to characterize the atmospheric composition of precursor manned habitats that house astronauts performing specific manned mission scenarios. Real time air quality data was collected during the Mission Operations Test of NASA’s Deep Space Habitat and during Mission 2 of the HI-SEAS Mars Analog Habitat. A portable FTIR was chosen because of limitations in crew time for conducting data collection and analysis.

Methods: A portable FTIR (Gasmet DX4040) was used for sampling real time air quality during both missions. The FTIR was zeroed using nitrogen periodically to obtain a background spectra. This background spectra and reference spectra are used for determining the concentrations of the gases and no other calibration is required. A predetermined method collecting up to 25 gases was used. The spectra were collected with a wand using the internal sampling pump of the FTIR. Results were displayed and recorded in a PDA. The portable FTIR was held at four fixed locations (core lab, hygiene module, plant growth system, and crew quarters) during the Deep Space Habitat mission. Sampling lines were laid out and the FTIR was moved by the crew during the mission. During the HI-Seas Mission 2, the FTIR was used in portable mode and used to routinely monitor gas composition in 3 locations (trash bin, living room, and plant/lab).

Results: Generally, changes in atmospheric composition and concentration were detected in different modules of the habitats. During the DSH mission, spikes in CO2 and ethanol were associated with periods of crew exercise as a result of increased metabolism and by the use of ethanol wipes to clean up after exercise. Cooking events were characterized by spikes in pentane, ammonia, and ethylene. Ethanol spikes were also measured when the crew used the hygiene module. During the HI-Seas mission, ethanol was highest in the food/water/metal/hygiene and in the paper/cardboard/plastic trash bins. Toluene was highest in the living room, where most carpeting was found.

Conclusions: The portable FTIR was very useful for measuring the background atmospheric composition, as well as, sudden increases in gas concentrations associated with distinct crew activities. These data are useful for understanding the interactions between human activities, habitat construction, packaging, and the air revitalization system of the habitat.

CS-102-06 Developing Effective Air Contaminant Bake-Outs

S. Evans, CIH, CSP, P.E., MDE, Inc., Seattle, WA

Situation/Problem: In a number of cases for projects, the scope of work included development of work plans to correct situations where volatile organic compounds or volatile non-organic compounds had “sunk” into fabrics, porous drywall and other porous and semi-porous surfaces within a residence. Detailed information on how to successfully bake-out a structure was not found in published literature. However, there were a few studies identified where select components that could be utilized to develop the appropriate method. The bake-out method needed to have the temperatures in the structure hot enough to drive the volatile substances out of where they “sank” into materials. However the method also had to consider minimizing ancillary damages such as weakening the glued furniture joints, and loosening adhesive under laminate countertops or wood or plastic veneers. Other concerns were excessive drying leading to cracks and checking of solid wood members.

Resolution: The limited studies found that a temperature range centered on 120°F maintained for 72 hours was shown to be most effective. My workplans were developed to incorporate this criteria and were further enumerated to include requirements to minimize the potential for damage. The methodology utilized will be discussed in detail.

Results: Once the bakeouts were conducted according to the workplans, the results in all cases indicated the absence of quantifiable concentrations of contaminants of concern were absent. Occupants that had been unable to live in the space due to negative reactions to the contaminants were able to live in the structures. The wallboard, carpet, etc. did not need to be replaced or wallboard painted.

Lessons Learned: Introduction of the heated air in multiple locations is more effective than when introduced at one location. Utilization of a contractor experienced in conducting bake-outs with stringent criteria was critical; they need less hand-holding that those without experience. Also, in addition to using recording temperature/humidity meters, a handheld digital temperature “gun” was utilized to verify temperature in every room. However, the results of a gun can vary depending on the color of the wall surface and distance from the target. A portable target (even a piece of paper) should be fastened to surfaces and the distance to the target marked to standardize the readings. Also, I need to write a paper on my multiple studies to ease the dearth of references available on bake-outs to others.