We examined associations between outdoor air pollution and childhood asthma, using measures of SES, neighborhood quality, and social support from the Los Angeles Family and Neighborhood Survey (LA FANS). We linked residential census tracts for 3114 children to government air monitoring stations and estimated average pollutant concentrations for the year before interview. CO and NO(2) levels increased and O(3) levels decreased as neighborhood quality decreased, yet correlations were low. Pollutant levels were not correlated with neighborhood support. Even after adjustment for social environment characteristics, LA FANS children living in high O(3), PM(10), and CO areas appeared to have worse asthma morbidity.