SACRAMENTO– A regulation requiring air districts to work more effectively at reducing the volume of smog-forming air pollutants moving from one district to another was passed today by the California Air Resources Board (ARB).

"These changes support the idea that neighboring air pollution control districts must work together to reduce emission sources under their jurisdictions -- air pollution does not respect boundaries," said ARB Chairman, Dr. Alan Lloyd.

Today's changes require upwind districts to take action towards reducing their smog impacts on downwind districts, in conjunction with efforts to reduce smog levels at home. This means that a district coming close to meeting ozone standards at home cannot cut back on smog-fighting efforts if its air pollution continues to impact a neighboring district.

The new provisions require districts to adopt all feasible measures to reduce the amount of ozone-forming pollutants flowing from one district to another. Districts will review their progress in adopting measures every three years, and consult with the public and neighboring districts. This will promote district collaboration and speed the adoption of new technologies.

The regulation also requires that districts use the same thresholds in determining whether new or modified stationary sources of air pollution need to reduce their emissions so there will not be a net increase in air pollution. Currently, some upwind districts have less stringent thresholds than their downwind neighbors.

"These changes add new measures that strengthen existing ARB rules on the issue of "transport" of ozone forming air pollutants from one district to another," Dr. Lloyd said.

The question of transport was most recently seen when air districts near the Bay Area Air Quality Management District claimed smog-forming emissions from the Bay Area were blowing inland into their districts. A major step toward alleviating this problem will come later this year when the Bay Area district begins using the more stringent enhanced smog check to reduce emissions from automobiles in the district.