May 2, 2013 12:04 PM by Ryan Haarer
TUCSON - Here in Pima County we've got good air quality 300 days out of the year but that could change.
There is no need to panic. The air is not getting more polluted. The measurement standards for gauging air quality are just changing.
The EPA recently changed the standard to measure even smaller pollution particles. These particles are 2.5 microns, a small fraction in size compared to a human hair.
So what does that mean for you? Pima County will see more moderate air quality days and fewer in the good range. The idea is to be more protective of public health, giving people with cardiovascular problems more of a heads up as to what they are walking into when they step outside.
These moderate days are usually seen during high wind days where particles are being kicked up, but now more stagnant days will see moderate days and the main culprit are motor and gasoline emissions.
The American Lung Association recently published their annual state of the air report. Tucson ranked in the top ten cleanest cities when it comes to year round particle pollution but that can be improved by taking fewer car rides, and by using newer cars with higher standards.