San Francisco is the latest county that's considering a mask mandate to help ease the spread of the delta variant. Public health officials say a decision could come as early as this week. Subsidies for electric vehicles have been hailed by environmentalists as a key clean energy policy. But do EVs actually reduce emissions? Guest: David Rapson, UC Davis Economics Professor  With wildfire smoke now a year-round problem in many parts of the state, Ventura County just launched a first-of-its-kind alert system to notify farmworkers when air quality conditions may pose a risk to their health.  Reporter: Matt Guilhem, KCRW  Among the San Joaquin Valley’s community of Punjabi Sikhs, there are many reasons people have been vaccinated against COVID-19. But many in these communities are also concerned that their vaccination concerns aren’t being addressed by health authorities. Reporter: Kerry Klein, Valley Public Radio Learn more about your ad choices. Visit megaphone.fm/adchoices