Particulate Matter Exposure of Rural Interior Communities as Observed by the First Tribal Air Quality Network in the Yukon Flat

Various studies linked high concentrations of PM_2.5 from wildfires and wood burning to respiratory and cardiac illnesses especially in sensitive people with preconditions, children, and elderly. In the rural Interior of America, medical emergencies often require air travel by charter for medical care, which contributes to elevated health care costs for rural villages.

Baselines of aerosol and meteorological surface data are vital for mitigation of air pollution, and any cost-efficient implementation of emission-control measures, policies, and intelligent decision-making processes. Such baselines can help identify sources, and direct the search for emission-control measures to mitigate health adverse air quality.

Recognizing the critical need of a baseline for improvement of human health, quality of life, conservation of prosperity, and ecosystem preservation in a rapidly changing world, the Tribes in the Yukon Flats, Alaska decided to step up to fill a gap in atmospheric near-surface data on their own to assess the quality of the air they are breathing. And a system of aerosol monitors and meteorological ground stations was placed in four Yukon Flats communities, and is managed by the Tribes of Ts’aahudaaneekk’onh Denh (Beaver), Gwichyaa Zheh (Fort Yukon), Jałgiitsik (Chalkyitsik), and Danzhit Khànląįį (Circle).

In this paper, the authors established a baseline inventory of air quality in the communities and to gain understanding of the sources of PM_2.5 within these Interior Alaska villages. The results showed radiative cooling under low surface wind speeds (<1 m·s−1 ) can lead to inversion formation and accumulation of local pollutants until winds or heating break the inversion and the pollutants are swapped out. ><1 m·s⁻¹) can lead to inversion formation and accumulation of local pollutants until winds or heating break the inversion and the pollutants are swapped out. As the warm season progressed, worst air quality was due to transport of pollutants from upwind wildfires. During situations without smoke or when smoke existed at layers above the surface inversion, concentrations of particulate matter of less than 2.5 micrometer in diameter or less (PM_2.5) were explainable by the local emissions; 24-h means remained below 25 μg·m^-3. When a cyclone governed the weather in the Interior, concentrations were lowest due to scavenging, washout and rainout. After the end of precipitation, typically concentrations built up to about the monthly baseline in about one hour. Occasionally, the change in wind direction associated with a frontal passage advected smoke from upwind fires to the community. When concentrations aloft were higher than in the village breaking of the inversion led to strong variations in concentrations due to the mixing processes of the two air masses of different degree of pollution.

Article by Stanley G. Edwin and Nicole Mölders, from USA.

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