February 10, 2021 7:52 am Air Quality: What Is It and What Does it Measure? NBC 7’s Sheena Parveen explains how air quality is measured and how data is collected in San Diego. US & World Videos 3:01 Woman confronts prowler in her Point Loma home 0:22 Police searching for trio accused of beating man outside downtown Tacos El Gordo 0:34 WATCH: Explosions heard as crews battle SUV fire 1:24 Evacuation orders issued again at energy storage facility 0:50 WATCH: PLNU pitcher snaps an aluminum bat in half!