Harvest dust can drive you nuts, but pales next to car exhaust

The almond harvest is upon us, and if you live or drive anywhere near an almond orchard, you know what that means.

Dust. And lots of it.

Depending on how close that orchard is, dust clouds can blanket your car and leave a layer of muck on your swimming pool. Worse, it could make you sick, or at least leave you coughing and wheezing.

“We definitely see more patients around harvest time,” said Dr. Dai Park, an allergist with Sutter Gould Medical Foundation in Modesto. “Some start their meds in the fall when they see that harvest start,” she said.

It’s no secret that local growers have responded to worldwide demand for the tasty, high-protein nut with a tidal wave of new almond orchards throughout the San Joaquin Valley, the most bountiful producer of almonds in the world. Led by Stanislaus County, harvested almond acres in the Northern San Joaquin Valley alone have surged more than 55 percent in 15 years and now account for a third of production in California.

“Harvesting is a dusty process,” acknowledged Gabriele Ludwig, director of sustainability and environmental affairs at the Almond Board of California, based in Modesto.

So, more almond trees must mean more dust, right? And more sickness?

The answer isn’t that simple.

Adding millions of almond saplings – the dustiest, by far, of all crops – no doubt brings more dust to the Valley. The almond industry, sensitive to public perception, anticipates a corresponding surge in protests and recently launched a multipronged drive to educate growers on keeping dust clouds to a minimum.

“We tell growers, ‘Look, your immediate world may not have changed, but now there are a lot more acres of almonds out there, and a lot more people, and there is more opportunity for what you’re doing to impact somebody,’ ” said Ludwig. Her group has produced a video series and technical guides on limiting dust at harvest, and the topic comes up in newsletters, urging growers – who grossed $6.8 billion in 2014 – to be respectful of neighbors.

Particle pollution, a component of air pollution, is on the rise, especially in the north Valley – Stanislaus, Merced and San Joaquin counties – according to the American Lung Association.

And California’s best-producing almond counties are also among the nation’s worst for particle pollution, the lung association reports. Kern County, which cranks out more almonds than any other, is first on the lung association’s bad list; Stanislaus, second-best in almonds, was lumped with Merced County for fourth-worst in the United States on the lung association’s list. Those in between are Fresno and Tulare, also major almond centers.

But the kind of dust kicked up in the almond harvest is a small component of particle pollution, and contributes only minimally to the most dangerous kind of particle pollution, or PM 2.5, say both the lung association and the San Joaquin Valley Air Pollution Control District.

The air district takes complaints on all air pollution sources, including dust. Without parsing for agricultural sources, the air district has received 945 dust complaints in Stanislaus and Merced counties in the past 10 years.

Here’s what’s surprising: Despite the almond surge – from 200,000 harvested acres in the north Valley in 2000 to 323,000 acres by 2014 – the number of fugitive dust complaints has not increased. In fact, except for small spikes in 2013 and 2014, complaints mostly have trended downward – 54 Stanislaus complaints last year, compared with 113 in 2007.

“Looking at the amount of pollution released into the air by agriculture and other businesses, we’re experiencing the lowest amount in our history, despite the growth in population, because of controls that have been put in place,” said Seyed Sadredin, executive director of the San Joaquin Valley Air Pollution Control District. And total air pollution, of which dust is only one component, has decreased 83 percent from 20 years ago throughout the eight-county San Joaquin Valley, Sadredin said.

His agency has implemented hundreds of rules in recent years, including tight restrictions on wood burning and other emissions.

The air district’s recent blow-up with federal environmental officials is far from resolved, and without a radical change, the Valley could not meet a particle matter standard even by removing all cars, trucks, farms and other businesses, the district says.

No one, however, is saying almond harvest dust is fun, or safe to breathe.

“Short-term exposure to particle pollution can kill. Deaths can occur on the very day that particle levels are high,” says the American Lung Association’s website.

Harvesting almonds kicks up 41 pounds of dust per acre – many times that of wheat, measured at less than 6 pounds per acre, or cotton at less than 4 pounds, according to a 2003 study, and row crops are even cleaner. The California Air Resources Board and other scholars have referred to that study over the years, although the almond industry has done others since and questions whether it’s still accurate. Machines in wide use today have reduced dust 30 to 40 percent compared with 20 years ago, the almond board has said.

The U.S. Environmental Protection Agency recently convoked a committee charged with proposing new standards for particle pollution, and two experts recommended a more careful look at exposure to harvest dust.

“We have to be concerned about exposure to all pollutants,” said Bonnie Holmes-Gen, a senior director with the lung association. “And agriculture certainly is a key source of pollution in the Valley.”

However, almond dust seems a small problem, she said, next to vehicle emissions, by far the major contributor to the Valley’s rising problem with particle pollution. And most of that increase is linked to the recent drought, the lung association and air district say, exacerbated in the summer by wildfires and in the winter by burning wood.

The lung association, in fact, found no spikes in particle pollution over many years during the almond harvest, generally September and October.

Holmes-Gen acknowledged that Stanislaus’ two air quality monitors – in downtown Modesto and a housing tract in Turlock – are not close to almond orchards. They might not pick up almond dust at all, she said, because unlike ozone – a wafting regional problem – particle pollution doesn’t stray far, mostly affecting those nearest by. Merced County also has two monitors, and San Joaquin County has three.

Sadredin said the 36 monitors throughout the eight-county air district actually rank among the highest concentrations for similar networks in the United States. Because vehicle emissions are mostly to blame for all air problems, Stanislaus monitors – following federal guidelines – were put in its most polluted places, and most people are exposed to lower levels of pollutants, he said.

Almonds passed milk a few years ago as Stanislaus’ most lucrative farm commodity, and now are California farms’ No. 1 agricultural export. The state produces all almonds in the country and accounts for 83 percent of global production, and a federal agency predicts a record crop this year.

It’s too early to tell whether the almond board’s campaign urging growers to limit harvest dust is working, Ludwig said. She’s heard stories of almond dust clouds stopping traffic on major highways, and of rural feuding farmers purposely directing harvest dust at the other’s property as a nuisance weapon. But most growers don’t like complaints and want to get along.

“There has been a fundamental change in how people view farming,” she said. “Twenty years ago, farmers were the salt of the earth. Now it’s, ‘Who are you and what are you doing?’

“We encourage almond growers and custom harvesters to take time to think about what they can do in their individual situation to try to minimize dust,” Ludwig continued. “That doesn’t mean there won’t be dust. But we ought to be thoughtful about how and when it’s emitted.”

This story was originally published September 10, 2016 at 7:45 PM with the headline "Harvest dust can drive you nuts, but pales next to car exhaust."