Bill would add public members to Valley district's governing body.

Long overdue changes in the makeup of the Valley air districts' governing board could follow a legislative compromise that now appears imminent. The upshot of the changes would be to somewhat reduce the influence of some special interests in the district's operations and boost the influence of the biggest special interest group of all: Valley residents who breathe the polluted air.

Senate Bill 999, sponsored by Sen. Michael Machado, D-Linden, would expand the 11-member board of directors of the San Joaquin Valley Air Pollution Control District by adding permanent representatives from the cities of Fresno, Stockton and Bakersfield, the Valley's largest.

It would also add two public members, appointed by the governor, with the approval of the state Senate. One would be a physician or scientist with expertise in pollution and its effects. The other would be someone in "environmental engineering, chemistry or meteorology, and who is a specialist in the public health impacts of air pollution," in the language of the bill.

Two other members would be chosen by other city councils, one from a town of 40,000 or fewer and the other from a larger city.

Each of the boards of supervisors in the eight counties of the district would continue to appoint one member apiece, bringing the new total on the board to 15.

It has taken a long time -- four years -- to get to this point. Fresno Assemblyman Juan Arambula kept the process alive, working very hard to achieve a compromise that had a chance in the Legislature. It isn't a slam dunk -- the county boards of supervisors have all opposed the idea strenuously and can be expected to continue to do so.

The opposition to expanding the district board comes mostly from those who prefer that the air district move forward slowly -- if at all -- in addressing the Valley's filthy air. For the most part, such groups fear that any changes in the status quo could cost them money -- setting aside the fact that everyone would be a great deal healthier if the air were cleaner.

The county boards, as a rule, are inclined to listen closely to those powerful groups, despite the fact that the interests of their broad range of constituents aren't well-served in that fashion.

Nor does this bill really threaten the status quo. County supervisors would still be in the majority on the air district board. An earlier version called for adding four public members; that proved much too progressive for the Legislature to swallow. Perhaps this compromise will go down easier.

We hope so. The Valley air district has made some progress in the battle for cleaner air, but the toughest parts of the fight are still ahead. A board with greater scientific expertise will be better positioned for that fight, even if only in a small way.