Apr 1, 2010 6:02 AM
PHOENIX (AP) Thursday marks the beginning of metropolitan Phoenix's six-month ozone reporting season.
The state had issued 31 health watches and six high pollution advisories in 2009.
Those results were an improvement over 2008, when there were 44 health watches and 11 high pollution advisories for the Phoenix area.
Officials say the fewer air pollution alerts in 2009 may be attributed to people driving less, using light-rail and lower June temperatures that kept ozone levels in check.
Ozone is a colorless gas that can irritate the eyes, nose and lungs and worsen existing heart and respiratory ailments.