Support for LAist comes from According to Michael Jerrett, a UCLA public health professor, Pacoima faces multiple challenges when it comes to air quality. For starters, the geography of the region, a valley, causes air-toxic chemicals, like nitrogen dioxide and ozone to settle near ground level. It’s like liquid in a bowl. That’s where small particles get into people’s lungs, where they can cause inflammation. It also doesn’t help that Pacoima is a big producer of those chemicals. Whiteman airport, Sun Valley power plant, the 5, 210, 118 freeways, and other industrial facilities pump pollution into an atmosphere where it is difficult to disperse.