Citation:

Fahey, K., A. Holder, M. Hays, T. Yelverton, H. Pye, N. Briggs, I. George, R. Gilliam, R. Kotchenruther, J. Martin, B. Murphy, AND G. Pouliot. Fuel testing, emissions analysis, and modeling to improve Fairbanks PM2.5. FY2020 R10 Fairbanks RARE First Stakeholders call, NA, May 27, 2020.

Impact/Purpose:

The is the first stakeholder meeting for FY20 RARE project to improve our understanding of sulfur emissions and transformation in Fairbanks, Alaska as well as better constrain total PM2.5 predicted in air quality models. Fairbanks is in serious nonattainment of the 24-hour PM2.5 NAAQS. Better characterization of the emissions and sulfur chemistry in the basin will facilitate better air quality management strategies.

Description:

Fairbanks, Alaska is a Serious nonattainment area for PM2.5 (particles with aerodynamic diameter <2.5 μm). The dominant chemical composition of PM2.5 during winter pollution events is organic carbon (OC), elemental carbon (EC), and ammonium sulfate. Source apportionment techniques have identified residential wood combustion as the main source of OC and EC. However, ammonium sulfate originates from a mix of sulfur emission sources including electrical generating unit (EGU) industrial coal and fuel oil and residential fuel oil, and source apportionment techniques have not been able to identify which sources contribute how much sulfate. The unknowns that inhibit implementing cost effective controls to limit sulfate are first, how much gaseous sulfur dioxide (SO2) and direct particulate sulfate are emitted from each source, and second, does the amount of SO2 converting to particulate sulfate differ from source to source in terms of the monitored impacts? Information is needed on how the various forms of sulfur emissions connect to observed sulfate at the air quality monitors. This will allow for identification of whose sulfur is ultimately the culprit in exceedances. To perform this analysis, we need to identify the mechanism for converting emitted SO2 into particulate sulfate, which has not been done for cold, low sunlight conditions of the Arctic winter. This proposal has three linked components. To better characterize sulfur emissions, we are proposing to conduct fuel composition testing for fossil fuels used in Fairbanks. To better characterize the overall chemical composition of PM2.5, we are proposing to test the emissions of volatile organic compounds from wood stoves as used in the Arctic, which can quickly condense to the particulate phase under Arctic conditions and have not previously been accounted for in emissions inventories. Lastly, we propose to use this information in conjunction with recent advances in air quality modeling to identify likely mechanisms for converting sulfur emissions to particulate sulfate.

Record Details: