Air Quality Monitoring at 40°C below Zero!

Most people think of the Arctic as a highly pristine clean environment, but this is not always the case. During the long dark Arctic winter, the urban atmosphere can become extremely polluted. Indeed, at some point during the year, the remote Alaskan city of Fairbanks turns into the most polluted city in the whole of the US.

This is due to the very cold Arctic winter when emissions of gases and particles (such as from wood-burning stoves, traffic, power stations) can become trapped locally at ground level due to the very stable meteorological conditions, with poor vertical mixing. Concentrations of gases and particles thus become very high, exceeding air quality limits as set out in The Clean Air Act and managed locally by the Alaska Department of Environmental Conservation. Fairbanks, Alaska is currently designated as a non-attainment area for PM_2.5 and a Maintenance Area for Carbon Monoxide.

In order to better understand these conditions, a research team was established to quantify air pollution in Fairbanks throughout the Arctic winter. Scientists Tjarda Roberts, Kathy Law, and Bill Simpson plus other experts from CNRS France research laboratories (LPC2E, LATMOS, …) and the University of Alaska (Fairbanks USA) are pursuing several objectives that can inform effective decision making to improve air quality. Specifically, to characterise local emission sources, understand the atmospheric processing of gases and particles and correlate the measurements of the atmospheric pollutants with observations of the local meteorology and boundary-layer conditions.

Tjarda Roberts explains, “for this, we needed reliable, automated instruments that could withstand the harsh Arctic winter conditions. We deployed two Praxis instruments from South Coast Science throughout the whole winter season (November 2019 to April 2020) to characterise gas and particle pollution at various sites across Fairbanks.

“The instruments measured CO, NO, NO2, Ozone, and size-resolved particles and operated autonomously throughout delivering high-resolution air quality data in real-time (via SIM card). The Praxis proved to be highly reliable under the extreme Arctic conditions, even as temperatures reached as low as -40 C.”

This work by Roberts et al. has an important contribution to make towards improving air quality and human health in the region. This isn’t a new problem. Back in 2018, the American Lung Association identified Fairbanks as the number one most polluted city for year-round particle pollution. This problem was compounded further last year by raging forest fires, reportedly degrading the air quality across most of the state.

Last winter's air measurement campaign* precedes a bigger international-effort on arctic wintertime atmospheric chemistry that is planned for this coming Winter in Fairbanks (unless delayed by Covid19), to which the US has committed significant funds in a project called ALPACA (Alaskan Layered Pollution And Chemical Analysis).

Where significant funds have been committed to assisting the understanding of air pollution, it is important that the outcomes provide value for money and support real, positive change. The high reliability of devices and measurements in this challenging environment creates robust data outputs. It also allows the researchers to concentrate on more sophisticated modelling. The incentives for change are made visible resulting in increased possibilities for action on air quality.

*Funded by the French National program LEFE (Les Enveloppes Fluides et l’Environnement), IPEV, Paris-OVSQ and Orléans Labex Voltaire.

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