[MUSIC PLAYING] There's just so far that you can go by treating people, treating them in the hospital or other settings. And if we really want to address health, we need to go upstream and figure out why it is that they're actually getting sick. And so I look at the relationship of human health to what's going on in our air, our water, our food. 

I also teach a class on sustainable agriculture and the public health implications. We go to some organic farms and a variety of places. The students also get to spend one day with a San Francisco food inspector going to restaurants around the city. And that has been an incredible experience for them. In January, they closed three restaurants down that day. I'm not going to name names, but some of them would be surprising to you. 

[MUSIC PLAYING]