1. Recent Trends In Ambient Air VOC and RSC Concentrations In The Athabasca Oil Sands Region Kevin E. Percy 1 & Tom Dann 2 1 Wood Buffalo Environmental Association, Fort McMurray, Alberta, Canada ; 2 R.S. Environmental, Ottawa, Ontario, Canada  Abstract The Wood Buffalo Environmental Association (www.wbea.org) has been monitoring ambient air quality in the Athabasca Oil Sands Region of Alberta since 1998. WBEA currently operates 18 fixed, and 4 portable monitoring stations for the continuous and semi-continuous measurements of criteria and non-criteria air pollutants. Current and historical raw and quality assured continuous data are publically available, while 2009-2013 semi-continuous data for VOC, RSC, PAH, and trace elements/ion in PM are publically available. By October, current and historical semi-continuous data along with essential metadata will become publically available.www.wbea.org WBEA follows Environment Canada (NAPS) protocols for semi- continuous measurement of VOC and RSC. Sampling is conducted for 24 hrs every 6 days using automatically-triggered Summa canisters. Sixty target VOC species and 20 target RSC species are analyzed for. The most recent 2010-2014 data from 8 air monitoring stations comprising a possible 2700 samples was examined. Patterns and trends within these data will be presented.  Introduction The Alberta Oil Sands comprise the third largest oil reserve in the world. The Athabasca Oil Sands Region (AOSR), largest of the three oil sand deposits, is situated in the northeastern corner of Alberta. Some 170 billion barrels of reserve are currently economically accessible. Of this, only 20% can be extracted by truck-shovel mining (below left), with 80% extractable by drilling using techniques such as SAGD (below right). Production is some 2.1 Mbpd at present. The Wood Buffalo Environmental Association (www.wbea.org) has been monitoring ambient air quality in the Athabasca Oil Sands Region of Alberta since 1998. WBEA currently operates 19 fixed, and 4 portable monitoring stations for continuous and integrated measurements of criteria and non-criteria air pollutants.www.wbea.org Current and historical raw and quality assured continuous data are publically available from 1998-present. Integrated data/metadata for VOC, RSC, PAH, and trace elements/ion in PM will be publically available at http://dev.wbea.org/monitoring-stations-and- data/historical-monitoring-data by December 31.http://dev.wbea.org/monitoring-stations-and- data/historical-monitoring-data  Results (cont’d)  Results  Methods & Materials  Discussion When comparing WBEA mean 2013-2014 24-hour sampled benzene concentrations to EC NAPS 2012-13 concentrations, the WBEA AMS concentrations were in the mid range for other NAPS locations. Collaborative EC-WBEA continuous BTEX measurement at AMS 1 indicates that hourly benzene concentrations can range between 1-3 ppb, or higher for short periods. Mean annual 24-hour benzene and toluene concentrations have declined at industrial AMS over six years. Six-year mean annual 24-hour acetaldehyde and methanol concentrations have increased at both community and industrial stations Methanol is generated by both industrial and natural (forest fire) processes Published WBEA real-world dilution stack sampling, and portable emissions measurement for mine heavy hauler emission factor/rate data is useful for understanding industry contribution to VOCs from two major source types. VOC concentrations measured do not clearly track emissions reported to NPRI (http://www.ec.gc.ca) for several reasons.http://www.ec.gc.ca WBEA will be expanding its list of target VOC in 2016.  Acknowledgements The authors thank WBEA ambient air technical staff for operation of the WBEA ambient air network. We acknowledge the support and funding by WBEA Members 2009-2013. We acknowledge funding beginning 2014/15 from the Alberta Environmental Monitoring, Reporting and Evaluation Agency (www.aemera.org) for ambient air measurementswww.aemera.org 2013-2014 Mean concentrations and 95% CI for most frequently-measured VOC during 2013-2014 are shown below. Mean 24-hour toluene concentration was highest at AMS 1 (0.68 ppb) with other community and industrial AMS having mean concentrations between 0.15-0.4 ppb. Mean 24-hour benzene concentrations ranged ranged between 0.17- 0.28 ppb. In 2013-2014, m,p-xylene mean concentrations ranged between 0.11-0.2 ppb, with mean ethyl-benzene and o-xylene concentrations between 0.03-0.07 ppb. Methanol was measured at the highest concentrations. During 2013-2014, mean methanol concentrations ranged between 5.0 - 19.8 ppb, with the highest concentration measured at AMS 7 in Fort McMurray. Acetone and acetaldehyde mean concentrations were similar, ranging between 2-4 ppb. 2009-2014 For the six-year period, Thiel-Sen analysis indicated a significant trend of decreasing benzene concentrations at industrial AMS, but only a small trend for community AMS. For the six-year period, Thiel-Sen analysis indicated a strong trend of decreasing toluene at industrial AMS, but no trend for community AMS.                                                                                 For routine measurement of VOCs and RSC in ambient air at 8 air monitoring stations (AMS), WBEA follows the Environment Canada (NAPS) SOP. Sampling is automatically triggered every 6 th day, and sampling occurs over 24 hours. Air is drawn into a Silcosteel® canister (below). The canister is shipped to a laboratory where the contents are withdrawn and analyzed using gas chromatography-mass spectrometry. Samples are analyzed for 63 VOC and 20 RSC compounds. For this analysis, 2009-2013 VOC data were considered. There was a maximum of 60 samples collected per AMS/year. The locations of the 8 AMS are shown in the image below. Community stations are in yellow, industrial stations in blue. Note that the community of Fort McKay is situate very near the four largest oil sands mining/upgrading operations. Few RSC routinely analyzed for were above method detection limits. Therefore, in this poster only VOC data are presented. The ten most frequently measured VOC at community AMS in 2014 are presented below for context purposes. AMS 1 Bertha Ganter-Fort McKay VOCFrequency (%) Maximum Concentration (ppb) Average ± 1 SD Concentration (ppb) Acetone85 %63.8 3.3 ± 4.9 Benzene72 %41.5 0.4 ± 2.7 Methanol63 %197 13.0 ± 28.4 Toluene62 %16.5 0.6 ± 1.9 Butane60 %105.0 1.4 ± 6.9 Isopentane60 %22.2 0.7 ± 1.7 Acetaldehyde49 %115.0 2.4 ± 7.7 Isobutane48 %59.6 0.6 ± 3.9 m, p-Xylene25 %3.97 0.1 ± 0.3 Isoprene23 %6.02 0.4 ± 1.0 Six-year mean annual concentrations of both acetaldehyde and methanol showed increasing trends at both community and industrial AMS.The increasing concentration trend for methanol was particularly strong. Below for context purposes, NMHC, benzene, toluene and xylene trends for Environment Canada (EC) measurements made at WBEA AMS 13 (http://www.ec.gc.ca/inrp-npri; NAPS 90806) and VOC emissions reported to NPRI are compared.http://www.ec.gc.ca/inrp-npri