It may seem like a small comfort after seven consecutive days of triple-digit temperatures, but residents of the Sacramento region are breathing easier this summer than they did during California's last major heat wave.
A combination of preferable weather conditions and federal, state and local efforts to reduce ozone emissions have paid off for people who care about their respiratory systems. Ten years ago, during a similar week of blazing temperatures, "our air quality would have been a lot worse," said Larry Greene, executive director of the Sacramento Metropolitan Air Quality Management District.
It's part of a bigger statewide success story that rarely gets attention amid all the "California is failing" stories. According to the California Air Resources Board, ozone emissions statewide have been cut by one-third since 2006. These compounds are created when nitrogen oxides and volatile organic compounds the byproducts of burning fossil fuels are heated by high temperatures and sunlight.
According to data published by the Sacramento Air Quality Management District, ozone pollution highs during this year's heat wave remained markedly lower than those posted in the half-month summer heat wave in 2006.
During that spell, which lasted from mid-July through the end of the month, ozone levels stayed at levels considered dangerous for the entire population for five days in a row. Outside of this streak, ozone readings remained primarily at unsafe levels for sensitive groups.
This year, there were only two days in which pollution reached high enough levels to pose a threat to sensitive groups.
This summer's heat wave was accompanied by steady winds, which may have kept smog levels lower than they might have been, said Jamie Arno, a spokeswoman for the Sacramento Air Quality Management District. Still, there is little doubt that government interventions deserve credit for a general improvement in air quality, here and in several other basins of California.
The California Air Resources Board pointed to new emission standards for light vehicles and a higher turnover rate for construction and trucking fleets as contributors. At a local level, projects such as the Voucher Incentive program, run by the air quality management district, have helped retrofit and even replace out-of-date diesel vehicles.
Since the program began in 1998, the district has paid out more than $200 million to put cleaner diesel fleets on the road, said Greene.
In 2006, the Sacramento Air Quality Management District put out alerts for 15 "Spare the Air" days, or spring and summer days in which ozone levels surpass federally established standards. By 2012, this number fell to 6, and none have been recorded so far in 2013.
With the growth expected in the years ahead, said Greene, the big challenge will be designing communities to cut down on "vehicle miles traveled" and resulting vehicle emissions. Improved transit and programs to enhance walking and biking will need to be part of this mix.
Despite recent improvements, Sacramento was ranked as the sixth most ozone-polluted city in the nation by a 2013 report from the American Lung Association. If we want to avoid the reputation of being a smog capital with all the restrictions that can come with federal non-attainment status the region will have to build on some of the things it is doing right.