PICACHO PEAK — It’s a hot and dry May afternoon and just off Interstate 10, on a side road close to Picacho Peak, stands Peter Hyde. His eyes are fixed on a plot of barren land dotted with dying palo verde trees, thin desert shrubs and grasses. And, he says, there aren’t as many as there should be.

A gentle breeze stirs, but it’s not nearly strong enough to dry his sweat-stained shirt or kick up any dust from the brittle brown ground beneath him. If the day were any drier or windier, Hyde wouldn’t want to be anywhere near here.

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During the summer monsoon season, this stretch of Pinal County can erupt in blinding clouds of grit and dust, brown curtains rising thousands of feet in the air, sweeping across a path miles wide. Wind whips the barren ground, gathering bits of whatever has settled on the desert floor, growing thicker as it scrapes fields and empty lots.

This is ground zero for many of Arizona's famed summer dust storms, sometimes called haboobs. The storms often originate hundreds of miles away, but it is here amid uncultivated farm lands and abandoned housing developments that the walls build, fortified by dust that can be measured in tons.

“It’s a force of nature," said Hyde, who has researched Arizona's summer storms. "You don't want to be out there."

A dust storm can cause chaos on the roadways as visibility plummets, often within minutes. Interstate 10 through Pinal County turns treacherous during the summer monsoon season: About half the 85 dust-related crashes between 2010 and 2015 occurred in a two-mile section near Picacho Peak, sometimes called the "Dust Corridor." Some of those crashes were fatal.

The health risks of breathing dust from the storms can be more far-reaching and long-lasting. State air quality monitors don't measure the precise content of dust, but the storms track through farm fields, livestock feedlots, industrial areas, unpaved roadways, landfills and old mines. As the storms die, the dust settles across neighborhoods, stirred up for days by wind, traffic or other activities.

And all the while, people breathe it in, whether at the height of the storm or the aftermath. The particles, called particulate matter by air quality regulators, are so small they can enter a person's lungs or bloodstream.

Dust particles are linked to a wide range of respiratory and cardiovascular health problems. People with preexisting conditions, along with young children and older people, are at highest risk. Dust pollution can trigger asthma attacks, contribute to lung cancer, heart attacks and premature deaths.

“For children still growing during the developmental stages, (dust) can lead to lifelong problems,” said climate scientist Ploy Pattanun Achakulwisut. “It affects lung growth and even brain development.”

Dust storms are difficult to predict, but experts say the conditions are unlikely to change soon. If drought persists, farmers in Pinal County will be forced to leave more land unplanted, leaving thousands of acres of soil exposed to the wind.

“The future is not bright for dust storms," Hyde said. "They're going to get worse and there are going to be more of them.”

A giant dust storm covers Phoenix on July 5, 2011. The storm was one of the largest on record in the area. Rob Schumacher/The Republic

Tracing the path of a dust storm

The swirling sands of a dust storm would seem to be a fact of desert life, but Arizona has grown dustier in recent years amid new development, mining operations and expanding farm fields, all human activities that disturb the desert landscape and expose the churned earth to winds.

And years of drought and an economic downturn worsened the situation as farmers and builders abandoned wide expanses of desert, contributing to some of the worst dust storms on record.

Dust storms follow unpredictable paths, but tend to blow up and move through a corridor from southern Arizona into northern Maricopa County.

Most storms peter out after 25 to 50 miles, losing strength as energy along the leading edge of the storm front dissipates.

But that wasn’t the case one day last summer.

On July 9, 2018, a dust storm formed just outside Phoenix and tore a 300-mile path before dying out in southeastern California.

Its epic proportions drew comparisons to a massive storm that occurred July 5, 2011 — a 100-mile wide, more than 1-mile-high storm that dumped 40,000 tons of dust on Phoenix in just two hours.

Last night’s dust storm (haboob) in #Phoenix made me feel a bit like I was on #Mars with its current dust storm raging.https://t.co/pGdcBKyZt2 pic.twitter.com/SXQQIk8YLU — Dr. Tanya Harrison (@tanyaofmars) July 10, 2018

The 2018 storm showed just how far dust can travel; the 2011 storm followed a more typical Arizona storm path.

The most active time for dust storm formation is during early monsoon season, June and July, said Jaret Rogers, lead forecaster at the National Weather Service in Phoenix.

Dust storms also develop outside the summer season, building with a dry cold front. While a summer storm can be over in three or four hours, a storm from a cold front can linger for half a day or more.

The most active path is in the heart of Pinal County. The weather agency recorded the starting locations for 34 dust storms between 2010 and 2018. Of those 34 dust storms, 21 originated in Pinal County.

From there, a northwest-blowing wind will drive the storm along I-10, marking a path to Phoenix known as the dust storm corridor.

The “wall of dust” people are familiar with is linked most often to summer thunderstorms, Rogers said. A dry monsoon storm doesn’t produce much rain and when the storm collapses, a burst of downward wind pushes up any dry, loose soil from the ground.

“It’s like throwing a rock in a pond,” Rogers described. “The dust storm forms along the ripple.”

A combination of wind and drought conditions means that, along the way, that cloud of dust picks up more dry, loose soil from unplanted farmland, construction sites and dirt roads. The outflow of wind from other storms can also cause a dust storm to redevelop over and over again.

Weather agencies, with improved technology, have gotten better at tracking dust storms, which used to rely heavily on human reports of dust storm sightings, Rogers said.

It's still a challenge, however, to predict when the next great dust storm will happen.

A dust storm passes along the north side of Tempe on July 9, 2018, tearing a 300-mile path before dying out in southeastern California. Patrick Breen/The Republic

Fields of disturbed dust

For all the questions about predicting storms, scientists are learning more about what's in them. Hyde, the ASU researcher, said the largest contributors are mine tailings, mostly from Hayden and Ajo; construction in areas from Tucson to Glendale; the Salt River Channel in Mesa; disturbed scrub desert in Yuma; and agricultural land around the state.

While abandoned agricultural land might not be the largest contributor now, it could be a more significant one in the future.

Decades ago, agricultural land surrounded Picacho Peak, but as water sources became more sparse, the land dried up, turned salty and transformed into miles of new dust storm fuel. Experts like Hyde want to keep soon-to-be-idled agricultural land from becoming abandoned and repeating the cycle.

Under the recently enacted Drought Contingency Plan, farmers in Pinal County will begin to lose access to Colorado River water. For now, they’re drilling wells to draw groundwater but those who can’t afford to do that will have to leave their land bare.

Over time, Pinal farmers would see a 62% reduction in water supplies. Some predictions foresee a 40% increase in uncultivated land in the next two to three years, and more in the coming years.

The latest 2017 government estimates show over 260,475 acres of idle or fallow agricultural lands across the state. Of that, 65,550 acres were in Maricopa County, 10,952 acres in Pima County and 56,496 acres in Pinal County.

That could further contribute to dust pollution and worsen the situation for large portions of Pinal County that are already failing to meet federal air quality standards.

The air Arizonans breathe turns deadly when summer dust storms roll through Drought, dirt roads, and fallow land all contribute to dusty air. Arizona Republic

Farmers who leave their land unplanted will still have to follow a few of the suggested guidelines and keep large-particulate (PM 10) emissions below a certain threshold. PM, or particulate matter, is a mix of dirt, dust, soil, ash and soot. They're finer than a grain of sand, allowing them to get caught in the respiratory system.

A best practices committee has suggested more than a dozen things farmers can do to keep dust emissions down, such as watering dirt roads and keeping crop residue on their land for a longer period of time.

Some farmers might be put in a tough situation and have to continue doing this for fallowed land that isn't producing income. Some will be compensated by the state under the Drought Contingency Plan.

Dan Thelander, a Tempe Farming Co. partner in Maricopa, says he may have to fallow 2,000 of his 5,000 acres because of looming water cuts. Cheryl Evans/The Republic

More dry farmland may mean more dust

Long-time Arizona cotton farmer Dan Thelander will have to decide which fields to fallow and find ways to save money.

Thelander prides himself on using drip irrigation, a system of poly tubing with strategically placed holes, that let him use only as much water as he needs. Not everyone can afford the system, which costs about $1,500 an acre to install.

Farmers like Thelander were expecting water cuts, but not for another 11 years. With shortages looming on the Colorado River, the flow of water into Pinal County will likely slow much sooner. At some point, Thelander said he may have to fallow 2,000 of his 5,000 acres. But even if farmers follow the rules and do what they can to mitigate dust, it’s never really enough to combat nature.

Battling climate change and dust can be costly for Arizona farmers, who are already facing other economic threats to their livelihoods. Cheryl Evans/The Republic

“It's difficult to deal with because even if your soil is in good shape, you're still gonna get a generation of some dust,” Thelander said.

“If you get 25- or 30-mile-an-hour winds, these dirt roads are still going to generate dust, and farmers can't afford to keep all the roads watered and the county can't afford to pave all the dirt roads," he said. "We live in a desert and it's difficult to deal with.”

Less water and more idle land would worsen conditions in western Pinal County, Hyde said. The region already emits hundreds of tons of PM 10 emissions into the air every year from agriculture and related activity.

As Arizona continues to adapt to a nearly two-decade drought, climate change will continue to make the state and the greater region hotter and drier, leaving the desert more vulnerable to these events.

“If you think about the present tense, the frequency and severity of dust storms as you go one decade, two decades, three decades in the future, both the frequency and the severity have got to increase, especially in Pinal county,” Hyde said, adding that those storms won’t likely stay in Pinal County, but encroach into Phoenix and other cities.

But every community around the state contributes, Hyde said, and the farmers should not be scapegoats.

The dust sources are intimately tied with human activities, from development to driving. While regulation and voluntary mitigation practices may have good intentions, Hyde said, they’re hard to enforce and they can only do so much. Deserts are dusty.

“There's no getting around it,” Hyde said,

“You can't live without polluting a little bit. It’s just the way the world works.”

Show caption Hide caption In the I-10 "dust corridor" just north of Tucson, University of Arizona researcher Joey Blankinship and his team are trying to change the composition of... In the I-10 "dust corridor" just north of Tucson, University of Arizona researcher Joey Blankinship and his team are trying to change the composition of the soil with compounds to add moisture and microbes that give loose soil some structural stability. Nathan J. Fish/The Republic

Mitigating dust pollution

On a piece of vacant desert near Picacho Peak, University of Arizona researchers Joey Blankinship and Kyle Rine are working on a series of tests they hope will lead to a natural, relatively cheap and long-lasting solution that improves soil health, the first step toward controlling dust.

Because there aren’t enough native plants on the empty parcels of land, Blankinship said, water doesn’t absorb into the ground as much. If it does, it breaks up the brittle soil, which can blow away when the water evaporates. Blankinship and his team have tried many things to keep the dust down, such as laying discarded plants, mulch compost and biochar, a charcoal-based soil additive, on top of the soil to try to keep it together.

While some of that, especially mulch, works, Blankinship said, mild winds can still blow it away. Instead, the team is trying to change the composition of the soil by using a patty of what are called biological soil crusts or “biocrusts.”

These crusts have moss, glycogen, lichen and cyanobacteria, all compounds that act as a natural glue that make the soil moister and more stable and add vital microbes that give loose soil some structural stability. Blankinship has been working on the land near Picacho Peak as a test site, a proof of concept he hopes to eventually take to a state or private investor.

The crusts also help fertilize the soil and take nitrogen out of the atmosphere, Blankinship said, and there’s a potential to cultivate them. One problem is that he can’t leave them alone; the biocrusts require intervention and upkeep in order to make sure they’re sticking to the soil.

That’s why Blankinship hopes once he shows a working proof of concept, people will invest more money, helping him find a better formula or a way for them to better manage themselves. The biocrusts might not be usable in certain areas given the conditions and are just one of many things that will need to be done to mitigate dust pollution.

“So besides microbes, which depending on soil chemistry and other factors and other soil properties, biocrusts might work better in some areas than in others,” Blankinship said.

“We're also looking at plants as a major component of the system. So not just thinking about soil but ways of improving the health of the soil so that plants can come in.”

Part of that is getting more water to seep into the soil by physically disturbing it in some way and planting more native plants in those areas — native plants that rely on Arizona’s sparse rainwater and don’t need much upkeep.

The Arizona Department of Environmental Quality and U.S. Department of Agriculture have also been trying to mitigate the problem. They often treat areas with “chemical dust suppressants” and encourage people across the state and in certain communities to participate in their voluntary programs.

Health issues keep Barbara Carpenter in her Phoenix apartment when air quality is at its poorest. Sean Logan/The Republic

The painful effects of dust pollution

Barbara Carpenter, a snowbird-turned-Phoenix retiree, often structures her day around the air quality forecast that she religiously reads. Carpenter has a progressive immune disease, one she doesn't fully understand but whose effects she knows all too well.

She looks out the window of her apartment at Piestewa Peak. She might be climbing that now, but because of her condition, this is usually the best view she gets of it if the air quality is too poor.

"None of the things we’re going to do in our society are going to matter if we can’t breathe,” Barbara Carpenter says. Sean Logan/The Republic

On those days, she sits in her soft armchair and enjoys the air-conditioning, reading with her husband behind shaded windows shut tight, draft-guarded doors and with a portable air machine within arm’s reach. If she absolutely has to leave, she’ll tuck away a mask in her purse just in case and stay inside as much as she can.

Carpenter takes such precautions, especially in the summer, because dust storms can happen in an instant. One day, she was at a tai chi class on what looked like a clear day, but when she left the class, she walked into the middle of a thick brown haze and could barely see where her car was.

She grabbed the mask from her purse and shuffled her way through the small parking lot, seeing only a few feet in front of her and she slowly drove home on the interstate. It was her first time in a storm as bad as that, but it felt oddly familiar.

“It was almost like being in a blizzard in the Midwest,” Carpenter said.

“It was just very eerie. I could see other car lights kind of glaring and I just went very, very slow on the right-hand side of the road."

Carpenter’s condition has robbed her of experiencing nature for the most part, but she’s made peace with her situation and has focused inward.

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She started a support group for people like her in her retirement community with help from the American Lung Association. They talk about their days, exchange advice and do breathing exercises aimed at focusing their attention on their breaths.

That focus on the present moment, Carpenter said, has reminded her of a more healthy perspective she can latch onto in her moments of sickness. She can’t change the air quality or the weather, but she can control how she deals with it.

She can breathe.

“We can’t stop living,” Carpenter said.

"“I’m here, it’s my home," she said. "I wish things were better. I wish the forces that could change some of the things would. None of the things we’re going to do in our society are going to matter if we can’t breathe.”

Dust as a public health menace

Airborne dust is a major component of particulate matter pollution in the Southwest and is linked to a variety of adverse respiratory and cardiovascular health problems, said Achakulwisut, the climate scientist.

The consequences from harmful dust pollution include asthma flare-ups, lung cancer, heart attack and even premature death — more than a thousand deaths in a year, according to recent statistics, and the number is possibly rising each year.

In April, the American Geophysical Union published a study that quantified how drought affects public health. Achakulwisut’s study found that dust pollution contributes to an estimated 1,300 premature deaths each year.

WHAT CAN BE DONE? State takes aggressive approach to detecting dust storms

By 2090, an additional 2,900 more premature deaths could be added each year, the result of a growing population, disease rates and dust levels affected by human-caused climate change. The rise in poor health could also increase economic damages by $47 billion per year by 2090.

"Further research is needed to conclusively identify the specific health impacts related to inhaling dust particles," Achakulwisut said. "But the evidence so far does suggest that desert dust is a toxic component of particulate matter."

While high levels of dust tends to affect most the people who spend a lot of time near the source, ambient dust can travel for miles and reach a large region, she added.

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Climate change spells a drier, dustier Arizona

The variability of monsoon season makes it difficult to predict if there will be more ferocious or more frequent dust storms, said state climatologist Nancy Selover. In the past five years, monsoon precipitation has varied from year to year.

There is one thing she has noticed: Arizona has been getting dustier.

“That’s been in large part due to the drought,” said Selover, a senior sustainability scientist at Arizona State University. “This year was a change. It was a lot wetter and rain helps lock the top layer of soil and dirt down. It’s not as easy for wind to pick up.”

But in the midst of a climate crisis, the return of drought looms as a possibility in the desert Southwest. The question, perhaps, is not when it’s going to happen, but what are people going to do about it.

Based on projections from climate models, the Southwest is going to experience increasingly dry conditions and higher levels of outdoor dust, Achakulwisut said. It’s going to take more than just peer-reviewed studies to respond to climate-driven threats, Achakulwisut said.

For Achakulwisut, the turning point when she went from scientist to scientist and climate activist came when she realized “the full scale and magnitude of the climate crisis and global air pollution.”

“I felt like we need action beyond the individual level, systematic changes” Achakulwisut said.

“I’m not a policy expert,” she admitted. “But I can read policy recommendations and draw informed conclusions and speak out. I think it’s an important issue.”

Ultimately, it might come down to a mix of climate policy and smarter land use.

“The first dust storm that was huge was in 2011,” Selover said. “We just had a booming housing market. Farmers decided to finally sell land to developers. Developers got excited. They plowed up all the ground, leveled it out, and then the bottom fell out of housing market. So they stopped.”

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The land no longer farmed or developed became enormous sources of dirt and dust, ready to be picked up after a dry winter, Selover said.

Dust pollution from human activities and disturbed land has become an immense problem that the state needs to solve, said ASU's Hyde, sitting at a picnic table at Picacho Peak State Park.

From his messenger bag, he pulled out a book of maps, outdated and worn. When he turned to the pages that show the area around the park, he pointed and traced the different colored plots of land. The colors indicate types of public land, state and federally owned.

“So why can’t the state fix it?" Hyde mused. "Well, the problem is immense. The expense is tremendous. The political will has yet to arrive.”

Do you have concerns about air quality in Arizona? Reach out to the reporters at Andrew.Nicla@azcentral.com and Priscilla.Totiya@azcentral.com. You can also reach Andrew at (602) 444-3821 and Priscilla at (602) 444-8092. Follow them on Twitter: @AndrewNicla and @PriscillaTotiya.

Environmental journalism on azcentral.com and in the Arizona Republic is supported by a grant from the Nina Mason Pulliam Charitable Trust. Follow the azcentral and Arizona Republic environmental reporting team at environment.azcentral.com and at OurGrandAZ on Facebook, Twitter and Instagram.