Plowing Under Southland Dairies Gets Environmental Agencies’ OK

It is an oft-repeated pattern across Southern California: farmland yields to the bulldozer’s blade.

But in contrast to other parts of the state, where pitched battles have been fought to save farms from urban sprawl, the rapid transformation of the dairy lands near Chino is being welcomed by environmental regulators as a significant step toward cleaner air.

Normally, replacing farms with suburbs would bring on more pollution from increased traffic. But for hundreds of thousands of people living in the Riverside area -- downwind from the dairies -- the biggest air pollution problem is a persistent haze of tiny particles, and dairy farms are one of the chief culprits.

Ammonia rises from the dairies -- an estimated 21 tons each day, making the farms the largest source of ammonia emissions in Southern California. The prevailing winds wafting over the region carry tons of nitrogen oxides produced by cars, power plants and factories.

The two chemicals mix in the air to produce tiny particles of ammonium nitrate -- the same stuff as lawn fertilizer -- swirling in the sky.

Health studies have linked particle pollution to maladies ranging from lost lung function to premature death.

Western Riverside and San Bernardino counties suffer from some of the worst particulate pollution in the nation.

But with houses replacing dairies, the plume of ammonia will continue to dissipate.

“In this case, growth will take out the cows and that will have a beneficial impact on particulate matter,” said Roger Atkinson, director of the Air Pollution Research Center at UC Riverside.

Haze blankets many of California’s inland valleys during warm weather, but it is especially abundant in the Inland Empire. A pollution sensor in Rubidoux consistently records the highest particle pollution levels in Southern California, and some of the top measurements in the nation. Throughout the year, the concentration of very small particles averages 31 micrograms per cubic meter of air in Riverside, more than double the federal health-based standard, government records show.

Under the right conditions, a person standing downwind from the Chino area can watch at midday as a billowing curtain of gray haze forms out of thin air as onshore breezes pass over the dairies. The towering mass contains billions of particles efficient at reducing visibility -- many of the specks are the diameter of the wavelength of light and scatter the sun’s rays -- and it descends on the area from Grand Terrace to Mira Loma.

Vicki Fitch, 35, is one of many who rely on their noses to tell which way the wind is blowing. She lives in the Bridlewood tract, one of Chino’s newest communities built in dairy land. Like her neighbors, her family wanted to live in a rural area, but they got more than they bargained for.

“It’s very odiferous. There’s a lot of fragrance and flies in the air,” Fitch said. “I use a lot of air freshener in the house, and I have to walk quickly from the house to get into the car,” she said.

Unlike other polluters, the dairies have escaped regulation of their emissions. Now, the South Coast Air Quality Management District is preparing a measure aimed at reducing emissions by at least half over the next decade.

The agency is considering more stringent rules on manure removal and greater use of “digesters” that derive methane fuel from manure.

Reductions in dairy fumes could create benefits that would ripple to big cities from Long Beach to the San Fernando Valley.

If dairy emissions are substantially reduced, smog goals for the region could be met without having to reduce as much of the nitrogen oxides produced by industrial sources farther west.