Environment News Service: Low-income populations, racial and ethnic minorities in California are exposed to greater levels of some air pollutants than higher-income, Caucasian populations. New research shows that as a result they suffer more asthma-related difficulties -- from asthma attacks and daily medication use to work absences and emergency room visits. In all, about 3.5 million adults and 900,000 children in California have been diagnosed with asthma. Millions more suffer from asthma-like breathing problems. Residents...