For decades, California Assemblywoman Cristina Garcia has been trying to clean up the air in polluted neighborhoods — first as an activist, then as a legislator. Recently, she celebrated her most significant victory: Governor Jerry Brown needed her help to extend California’s cap-and-trade program. In return for her support, she got the legislature to pay attention to not just greenhouse gases, but all the accompanying nasty that pours out of smokestacks. The result: California’s most significant air-pollution law in years.