People don't think about dust much until it's time to clean the house, but a new report by UC researchers could raise awareness of the growing threat of dust and dust storms.
Dust affects everything from cardiovascular and brain health to traffic collisions and agricultural yield. “Beyond the Haze: A UC Dust Report on the Causes, Impacts, and Future of Dust Storms in California” details the wide-ranging impacts of dust on health, public safety, the environment and California's economy.
“Dust events are a big problem, especially in the Central Valley, and have not gotten enough attention,” UC Merced Professor Adeyemi Adebiyi said. “One of the goals of the report is to highlight that.”
Dust is a naturally occurring phenomenon that defines the desert climate zone that makes up most of the state. The regions where dust storms occur encompass an area greater than 55,000 square miles and are home to nearly 5 million Californians. To put these numbers into perspective, this is an area and a population greater than almost half of the states in the United States.
Led by Amato Evan, a climate scientist at UC San Diego’s Scripps Institution of Oceanography, and funded by a grant from the UC Office of the President, the researchers represent seven of the UC’s 10 campuses. Two researchers from UC Merced, both Health Sciences Research Institute members, contributed their expertise.
The collaborative compiled “Beyond the Haze” by synthesizing work from hundreds of scientific publications and recent reports to conclude how dust affects California's people and resources, including water resources, solar energy production, agricultural productivity, and weather and climate.
For example, dust can be laced with industrial chemicals and pathogens that can cause severe respiratory illnesses or death. Unfortunately, the report points out, vulnerable groups disproportionately bear these health impacts.
Valley fever, caused by a fungus, is one of the illnesses that relies on dust to spread.
“Valley fever risk increases as the amount of dust increases,” UC Merced immunology Professor Katrina Hoyer said. “We don't yet know how the dust interacts with the fungus in triggering the host immune response, but a recent study at the University of Nevada found an association between fine mineral dust and Valley fever incidence.”
Dust is made of fine particles of solid matter. It generally consists of particles in the atmosphere from various sources such as soil lifted by wind, volcanic eruptions and pollution.
Much of the dust in our homes is composed of dead skin cells. The rest, and in offices and other built environments, comprises small amounts of plant pollen, human hairs, animal fur, textile fibers, paper fibers, minerals from outdoor soil and other materials that may be found in the local environment.
Pollution is a complex mixture of solids and aerosols composed of small droplets of liquid, dry solid fragments and solid cores with liquid coatings. Particulate matter (PM) with a diameter of 10 microns or less (PM10) are inhalable, and matter classified as PM 2.5 is particularly concerning because it can penetrate deep into the lungs and even enter the bloodstream.
“We hear about PM 2.5 and PM 10 and pollution all the time — but some people don't realize part of that metric is dust,” Adebiyi said.
PM 2.5 has been linked to various forms of dementia, cardiovascular problems, COPD, asthma, and perhaps most surprisingly, longer and more painful menstrual cycles.
Masks protect against the fungal spores that cause Valley fever and many other potentially dangerous inhalable particles, including airborne viruses such as COVID. But, Hoyer said, many people don't want to wear masks while working in the heat outside.
In addition to health problems, reductions in visibility during dust storms often result in significant traffic accidents. Dust storms reduce agricultural productivity due to the loss of fertile topsoil and abrasion of crops by airborne particles, which is particularly critical given the state’s role as the leading agricultural producer in the United States.
“California, particularly the Central Valley, has not been considered an important dust source,” said Adebiyi, who studies dust and its impacts. “However, we're beginning to see, with recent events, that the Central Valley is a major contributor, and much of its dust comes from agricultural sources.”
When blowing dust settles on solar panels, the ability to generate electricity from the sun is diminished, hampering the state's transition to renewable energy sources. Dust whipped up from the state’s arid regions during the winter and spring can settle on the snow covering the Sierra. The report indicates that this causes a darkening of the snowpack and encourages melting earlier than would otherwise occur, negatively impacting the state’s critical water resources.
The report authors hope their work yields more support from state and local governments to help impacted communities minimize exposure to dust by generating timely and accurate forecasts of dust and characterization of what people might be breathing in when it is aloft.
“Legislatively, we need more studies to understand better how all these things go together, understand the dust patterns, and develop dust mitigation strategies,” Hoyer said. “Farmers have been working hard over the last decade to develop ways to reduce dust during harvest. I think more resources must be spent helping with that effort and finding ways to mitigate the infectious materials that may accompany that dust.”
Although dust storms affect millions of Californians, communities don’t have reliable forecasts of when, where, and for how long they will occur, Evan said, nor is there an early-warning system that can alert them when dust storms are on the way so they can protect themselves.
The report summarizes the past and likely future of dust in the state. Historical records indicate dust emissions in the state are now greater than at any other period, and computer model simulations suggest the aridity driven by climate change will further fuel this trend of increasing dustiness.
Adverse health impacts are expected to increase in the San Joaquin Valley, which already has some of the most polluted skies in the United States.
Similarly, other adverse impacts of dust on California, its environment and its climate are also expected to become more severe with time.
“Dust hasn't really been considered part of the climate change puzzle, but it is a great readout of climate change. Drought and changing weather conditions are impacting the amount of dust in the air,” Hoyer said.
“The future of dust in California is still uncertain. Our report suggests dust storms will likely increase,” Adebiyi said. He said one reason for that is policies such as the Sustainable Groundwater Management Act, which requires farmers to try to limit the amount of water they use.
“One consequence is that Central Valley farmers may have to fallow or abandon about 1 million acres of land to comply with the law. That is a lot of land that can become exposed to wind erosion, resulting in another dust source,” he said. “Another factor is climate change. We are vulnerable to drought and heat waves in the Central Valley, and these climate impacts are predicted to worsen, potentially contributing to more dust emissions.”
