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Comparison of Passive and Active Air Sampling (PAAS) Methods for PCBs – A Pilot Study in New York City Schools
Hunt, G., M. Lorber, K. Thomas, M. Maddaloni, E. Gerdts, E. Denly, J. Bourbon, AND A. Signa. Comparison of Passive and Active Air Sampling (PAAS) Methods for PCBs – A Pilot Study in New York City Schools. Dioxin 2017, Vancouver, CANADA, August 20 - 25, 2017.
The Region 2 RARE project presentation describes a comparison of active versus passive sampling methods for PCBs in school indoor air. If successful, passive sampling methods may provide a more feasible and cost effective approach for measuring PCBs in school and other types of buildings.
PCBs were used extensively in school building materials (caulk and lighting fixture ballasts) during the approximate period of 1950-1978. Most of the schools built nationwide during this period have not had indoor air sampling conducted for PCBs. Passive air sampling holds promise as a lower cost, easily implemented method for sampling in school buildings. It has the benefit of providing a longer time-integrated sample than an active pump-assisted method and may be more suitable for use in occupied buildings. However, the performance of a passive sampling device against an accepted active sampling method in an actual school setting has not been established. This study was designed to address this data gap. It also aligns with US EPA’s Office of Research and Development National Exposure Research Laboratory’s (ORD NERL) recent efforts to characterize sources and exposure potential for PCBs in schools. In cooperation with the USEPA, two school buildings with indoor air PCB concentrations expected to be above 50 nanograms per cubic meter (ng/m3) were selected for the PAAS Study. As part of a 2010 Consent Agreement between the City of New York and the USEPA, the City had undertaken a comprehensive PCB Pilot Study to evaluate the possible presence of PCB-containing caulk in public school buildings and preferred remedial remedies. School A and School B were selected from the five Pilot schools for this PAAS Study based on review of historic air sampling data which had shown indoor air PCB concentrations in specific areas of the school in the range of 50-500 ng/m3. Screening level air sampling by an active method was performed in two locations in each of the two (2) selected schools prior to performing the 6-day school air sampling to ensure that the selected schools had PCB indoor air concentrations in the targeted range (50 – 500ng/m3. This sampling occurred during September of 2016. Upon confirmation that screening level concentrations were acceptable, four locations, within each of the two pilot schools, were identified for the side-by-side PAAS. Screening air samples were analyzed in accordance with SW846 Method 8082A with a target detection limit of approximately 50 ng/m3. The screening air sample results ranged from 49.8 ng/m3 in the Therapist Room 118 (formerly a classroom) at School A to 478 ng/m3 in the Southwest Stairs D (top half-landing) at School B. Results of the PCB screening air sample analyses were found to be in the range of 50 -500 ng/m3 and therefore these locations were acceptable to be included in the PAAS Study. The full study PAAS air sampling was conducted over a six (6) day sampling event from October 7 to 13, 2016 when school was not in session. Four locations in each school were identified, leading to a total of 8 locations. Each location had a collocated pair of active and passive samples, and these samples were the focus of the study. Results were determined for PCB Aroclors and PCB congeners; this abstract focuses only on the PCB congeners. Active air samples were collected using a low-volume SKC AirChek® XR-5000 personal sampling pump equipped with a glass cylinder containing a polyurethane foam (PUF) sorbent for the collection of PCBs in accordance with EPA Method TO-10A. For each location, three active 48-hour samples were collected in series to allow for data representative of the 6-day sampling duration needed for the passive samples and for subsequent comparison of results of the two sampling methods. Each active sample was collected at a flow rate of 2.5 liters per minute (lpm) with a sampling period of 48 hours for a resulting total air volume of approximately 7.2 m3 for each of the three 48-hour active samples in series. This resulted in a total volume of approximately 21.6 m3 or 21,600 liters of air for each active sample. Tisch Environmental Model TE-200-PAS Passive Air S