L.A.'s smog tops Houston's
Associated Press
LOS ANGELES — The greater Los Angeles region surpassed Houston and the San Joaquin Valley as the nation's smog capital, in part because of a change in method of ranking, federal officials said.
Houston and the San Joaquin Valley, which in recent years rivaled or surpassed Los Angeles as the country's smoggiest areas, ranked lower this year.
But Los Angeles' rank comes with an asterisk.
The EPA this year switched from measuring smog over a one-hour period to measuring it over an eight-hour span. Under the old system, Houston would have edged out Los Angeles for the top spot by violating the standard on 33 days compared with 30 days.