Some late summer season heat waves created enough smog to give the region nine excessively smoggy days in 2010, compared with eight days last year. Still, that's clearly much better than the Los Angeles basin area that had 103 days and 83 days in the San Joaquin basin.
These days are counted as excessively smoggy when ground-level smog concentrations violate federal health standards.
When the ozone increases like this, air officials typically call 'Spare the Air' Alerts.
