I didn't grow up there during that time, but moved there in the late 70's. There were indeed many smoggy days. But surprisingly it got much better after about 10 years. I assume it was a result of stricter regulations. These days the air quality in the LA area is generally pretty good, with historical PM2.5 data showing "green" most of the time http://aqicn.org/city/los-angeles/
