Submitted to: International Conference on Modelling, Monitoring and Management of Air Pollution
Publication Type: Proceedings
Publication Acceptance Date: 9/22/2008
Publication Date: 9/24/2008
Citation: Sharratt, B.S., Feng, G. 2008. Fugitive dust emissions from agricultural land within the Columbia Plateau, USA. International Conference on Modelling, Monitoring and Management of Air Pollution .
Technical Abstract: Windblown dust originating from agricultural land has contributed to poor air quality within the Columbia Plateau region of the Pacific Northwest United States. In fact, the US EPA national ambient air quality standard for PM10 (particulates 10 µm or smaller in diameter) is exceeded each year in eastern Washington due to wind erosion of agricultural land. Winter wheat - summer fallow is the conventional crop rotation employed on more than 1.5 million ha within the region. During the 13-month summer fallow period, multiple tillage operations are performed to conserve soil water and control weeds; these tillage operations also result in erosive soil conditions. No previous studies have assessed the loss of soil or PM10 from agricultural fields during high wind events within the Columbia Plateau. Therefore, instrumentation was installed to measure sediment and PM10 flux at the windward and leeward positions in a field maintained in summer fallow. Soil loss occurring as a result of singular high wind events ranged from 0 to 2320 kg ha-1 over a four year observation period. Suspension-sized particulates (smaller than 100 µm in diameter) comprised greater than 90% of the eroded sediment, indicating that direct suspension and not saltation was the dominant erosion process. The corresponding loss of PM10 occurring during singular high wind events ranged from 0 to 210 kg ha-1. Loss of PM10 comprised 5 to 12% of the total soil loss. Although loss of PM10 during high wind events is relatively small compared to total soil loss, such quantities are sufficient to degrade air quality. Therefore, alternative tillage or cropping practices are sought that will reduce the loss of topsoil and PM10 from summer fallow fields during high wind events.