SALT LAKE CITY (AP) -- Despite the growth in population and auto use, Wasatch Front summertime air is cleaner than it was 20 years ago.
"From the '80s, the ozone (level) has gone down dramatically," said Cheryl Heying of the Utah Division of Air Quality.
State regulators cite the vehicle inspections and maintenance programs that ensure that vehicle pollution controls remain in good order and the fact that vehicles are built to produce less pollution than they used to.
There also have been equipment improvements mandated at electric utilities that lower nitrogen dioxide and volatile organic compounds that combine in hot weather to create ozone.
In addition, new companies are required to keep their pollution low or buy pollution credits from other companies.
The technological improvements in containing auto emissions are important because vehicles account for more than two-thirds of the area's air pollution.
"What's making the difference is the cars are cleaner and getting cleaner all the time, so when we retire a junker and bring a new one on, it makes a big difference," said Sam Klemm, spokesman for the Wasatch Front Regional Council.
"By 2030, we're going to have 1.4 million people in the Salt Lake Valley, but the trend line looks good because the cars will be that much cleaner. The automobile portion of the pie is improving," Klemm said.
Pollution is at its worst during the hottest and coldest months.
In winter, the fine particles left over from combustion are the biggest problem, especially when extended inversions trap the scummy air in valley basins.
The state established a no-burn program to help improve the winter air-quality during those inversions. The number of coal and wood burning stoves fell from more than 5,000 to fewer than 2,000 during the 1990s.
In summer, the problem is ozone, 78 percent of which is blamed on combustion engines. Sunlight and heat cause the hydrocarbons and nitrogen oxide in emissions to form ozone.
Despite the gains, demographic projections by the state Division of Air Quality suggest the state and industry will have to keep making strides in technology and regulation or Utah's population growth will overwhelm the controls by 2030.
(Copyright 2003 by The Associated Press. All Rights Reserved.)