Numbers in the chart below show the Air Quality Index for today, based on an average over time. Because fires can cause high hourly levels of particulate matter (PM), which is harmful to breathe, it is important to check hourly readings on the Station Data page in addition to the chart below. See information on Smoke and Health. The Index below presents ratings for: ozone, a principal component of smog; particulate matter smaller than 2.5 microns in diameter (PM2.5); and particulate matter smaller than 10 microns in diameter (PM10). Note: all data are preliminary and subject to verification. To view exceedances of standards, see Days Exceeding Ozone and Particulate Standards. Temporary air monitoring for particles (PM2.5) has been installed in Santa Ynez. To see an air quality report for that station, see this website. Also see smoke reports for California wildfires posted on California Smoke Information site.