1. Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles (UCLA), Los Angeles, California, USA
2. Department of Environmental Health Sciences, Fielding School of Public Health, UCLA, Los Angeles, California, USA
3. Department of Atmospheric & Oceanic Sciences, UCLA, Los Angeles, California, USA
4. Department of Chemistry, University of California, Irvine, Irvine, California, USA
5. Environmental Health Sciences, School of Public Health, University of California, Berkeley, Berkeley, California, USA
6. Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Quebec, Canada