North Carolina residents breathed a little easier this summer.

The News & Observer of Raleigh reported Tuesday that the state's air quality was the best in three decades as environmental laws, balmy weather and the recession combined to make the air cleaner.

The Department of Environment and Natural Resources said Monday that North Carolina had six "code orange" days, the lowest number since some local governments began tracking air quality in the early 1970s. Code orange means ground-level ozone levels exceeded federal clean air standards.

The state had 36 days of unhealthy ozone levels last year and 66 in 2007.

On "code orange" days, state officials urge children, the elderly and people with asthma to avoid strenuous outdoor activity.