Today was an Air Quality Action Day in Utah. PM2.5 concentrations reached Code Yellow and Orange (Moderate to Unhealthy for Sensitive Groups) AQI levels, as shown in the EPA Airnow AQI animation below. Concentrations ranged from 11 to 49 ug/m3, as shown in the Airnowtech PM2.5 timeseries. The Utah Department of Environmental Quality adviced the public to voluntarily not use wood coal burning stoves fireplaces, and reduce vehicle use by consolidating trips. Industry was advised to optimize operations to minimize air pollution emissions. AOD retrievals over Utah were not possible due to cloud coverage, as shown in the MODIS Aqua RGB image. California experienced high AOD retrievals as pollution settled along the San Joaquin River Valley, as shown in GASP animation.