From Source to City: Particulate Matter Concentration and Size Distribution Data from an Icelandic Dust Storm

Abstract:

Dust storms are the source of particulate matter in 20%-25% of the cases in which the PM₁₀health limit is exceeded in Reykjavik; which occurred approximately 20 times a year in 2005-2010.

Some of the most active source areas for dust storms in Iceland, contributing to the particulate matter load in Reykjavik, are on the south coast of Iceland, with more than 20 dust storm days per year (in 2002-2011).

Measurements of particle matter concentration and size distribution were recorded at Markarfljot in May and June 2015. Markarfljot is a glacial river that is fed by Eyjafjallajokull and Myrdalsjokull, and the downstream sandur areas have been shown to be significant dust sources. Particulate matter concentration during dust storms was recorded on the sandur area using a TSI DustTrak DRX Aerosol Monitor 8533 and particle size data was recorded using a TSI Optical Particle Sizer 3330 (OPS). Wind speed was measured using cup anemometers at five heights.

Particle size measured at the source area shows an extremely fine dust creation, PM₁ concentration reaching over 5000 µg/m³ and accounting for most of the mass. This is potentially due to sand particles chipping during saltation instead of breaking uniformly. Dust events occurring during easterly winds were captured by two permanent PM₁₀ aerosol monitoring stations in Reykjavik (140 km west of Markarfljot) suggesting the regional nature of these events. OPS measurements from Reykjavik also provide an interesting comparison of particle size distribution from source to city. Dust storms contribute to the particular matter pollution in Reykjavik and their small particle size, at least from this source area, might be a serious health concern.