Kaarle Kupiainen

Experimental studies about the impact of traction sand on urban road dust composition

Traffic causes enhanced PM(10) resuspension especially during spring in the US, Japan, Norway, Sweden and Finland, among other countries. The springtime PM(10) consists primarily of mineral matter from tyre-induced paved road surface wear and traction sand. In some countries, the majority of vehicles are equipped with studded tyres to enhance traction, which additionally increases road surface wear. Because the traction sand and the mineral matter from the pavement aggregate can have a similar mineralogical composition, it has been difficult to determine the source of the mineral fraction in the PM(10). In this study, homogenous traction sand and pavement aggregate with different mineralogical compositions were chosen to determine the sources of PM(10) particles by single particle analysis (SEM/EDX). This study was conducted in a test facility, which made it possible to rule out dust contributions from other sources. The ambient PM(10) concentrations were higher when traction sand was used, regardless of whether the tyres were studded or not. Surprisingly, the use of traction sand greatly increased the number of the particles originating from the pavement. It was concluded that sand must contribute to pavement wear. This phenomenon is called the sandpaper effect. An understanding of this is important to reduce harmful effects of springtime road dust in practical winter maintenance of urban roads

Fatty acids on continental sulfate aerosol particles: FATTY ACID SURFACTANTS

Published 2005 American Geophysical Union. Reproduced by permission of American Geophysical Union.

Review of Road Dust Emissions

Abstract Non-exhaust emissions from road dust, such as particulate matter (PM) available for suspension from the road surface, can be a significant contributor to traffic-related PM emissions. The sources of road dust can be many and varied and include traffic-related wear of roads, tires, and brakes, as well as a range of other sources, such as traction sanding, road salt, atmospheric deposition, migration, or entrainment from roadside dust or construction sites. The contributions vary depending on location, tire types, road surface quality, etc. Processes affecting road dust loading and emission include traffic suspension rates, driving patterns, road drainage, and vehicle spray. Importantly, meteorological conditions, such as road surface wetness, have a strong controlling impact on road dust retainment and suspension. As vehicle and road wear sources, often referred to as being direct emissions, can also be deposited on the road surface to become road dust, care should be taken in describing these sources, to avoid any double counting.