Air Quality Information

for the Sacramento Region

Thursday, clear overnight skies and calm winds have allowed surface temperatures to cool in the Sacramento region, producing a strong temperature inversion. This inversion has reduced vertical mixing in the atmosphere, trapping pollutants near the ground. In addition, morning fog and mist have enhanced particle production, and calm to light winds throughout the day will limit pollutant dispersion. These conditions, combined with carryover pollutants from previous days, will lead to Unhealthy for Sensitive Groups particle levels. Friday, an overnight temperature inversion and calm morning winds will continue to limit mixing and dispersion in the Sacramento region, allowing pollutants to accumulate through the morning hours. However, as a weak upper-level trough of low pressure moves through northern California, increased atmospheric mixing and light to moderate northerly winds will develop in the afternoon, dispersing some pollutants. Therefore, particle levels will be Moderate. Saturday, an upper-level ridge of high pressure will build over northern California, reducing vertical mixing. Furthermore, as surface high pressure settles over Nevada, winds will diminish in the Sacramento region, reducing pollutant dispersion. As a result, particle levels will be Unhealthy For Sensitive Groups.