Overview of the Alaskan Layered Pollution and Chemical Analysis (ALPACA) Field Experiment.

The Alaskan Layered Pollution And Chemical Analysis (ALPACA) field experiment was a collaborative study designed to improve understanding of pollution sources and chemical processes during winter (cold climate and low-photochemical activity), to investigate indoor pollution, and to study dispersion of pollution as affected by frequent temperature inversions. A number of the research goals were motivated by questions raised by residents of Fairbanks, Alaska, where the study was held. This paper describes the measurement strategies and the conditions encountered during the January and February 2022 field experiment, and reports early examples of how the measurements addressed research goals, particularly those of interest to the residents. Outdoor air measurements showed high concentrations of particulate matter and pollutant gases including volatile organic carbon species. During pollution events, low winds and extremely stable atmospheric conditions trapped pollution below 73 m, an extremely shallow vertical scale. Tethered-balloon-based measurements intercepted plumes aloft, which were associated with power plant point sources through transport modeling. Because cold climate residents spend much of their time indoors, the study included an indoor air quality component, where measurements were made inside and outside a house to study infiltration and indoor sources. In the absence of indoor activities such as cooking and/or heating with a pellet stove, indoor particulate matter concentrations were lower than outdoors; however, cooking and pellet stove burns often caused higher indoor particulate matter concentrations than outdoors. The mass-normalized particulate matter oxidative potential, a health-relevant property measured here by the reactivity with dithiothreiol, of indoor particles varied by source, with cooking particles having less oxidative potential per mass than pellet stove particles.

Managing Alaska's Road-Dust Problem: A Model for Road Dust-Impacted Regions.

Poor air quality in Alaska's remote communities due to road dust is one of the top environmental concerns of residents in these communities. Most communities are disconnected from the road network, with community roads that are predominantly unpaved. In Alaska, high costs limit widespread paving of roads, leaving communities to rely on alternative dust control strategies. The goals for this study were to assess the magnitude and impact of the dust problem in rural Alaska and use a diversity of experience, including regulatory, research, engineering, and cultural, to develop a road-dust management approach for rural Alaska. The plan incorporates different levels of dust management: institutional controls, road watering, chemical dust suppressants, and road surface stabilization. Geographical zones where use of each different dust management level will be most appropriate are identified based on rainfall frequency. Approximately 50% of Alaska's communities can manage road dust with institutional controls and road watering. Many of the road-dust management ideas presented are transferable to other global regions that experience similar economic and community access challenges as Alaska.