Saturday's dust storm in eastern Washington triggered high air-pollution levels in Kennewick and Spokane, according to preliminary data collected by state and local air-quality agencies.

At monitoring stations in Kennewick, operated by the Benton Co. Clean Air Authority, and in Spokane, operated by the Spokane County Air Pollution Control Authority, pollution from airborne particles averaged more than two times the national standard for healthy air. Based on an index where 100 is the health standard, the pollution level was 224 in Kennewick and 268 in Spokane. The U.S. Environmental Protection Agency classifies pollution in that range as "very unhealthy." Both readings are preliminary and not part of official air-quality records.

Airborne dust particles are "particulate matter," one of the basic types of air pollution monitored in Washington. Particulate matter in dust storms is very small and can be inhaled deeply into the lungs, where it can damage sensitive tissues. People with respiratory illnesses, the elderly, young children, pregnant women and anyone engaged in strenuous physical activity outdoors are most at risk.

• The interaction of soil dryness, wind speed and practices used to manage open ground on farms, construction sites, dirt roads and other facilities affect the level of dust emissions. For additional background information:
  

Local contacts:

• Benton Clean Air Authority, 509-943-3396.
• Spokane County Air Pollution Control Authority, 509-477-4727.