Desert dust storms carry human-made toxic pollutants, and the health risk extends indoors
Published in Science & Technology News
Humans have contended with dust storms for thousands of years, ever since early civilizations appeared in the Middle East and North Africa. But modern desert dust storms are different from their preindustrial counterparts.
Around the world, deserts now increasingly border built structures, including urban dwellings, manufacturing, transportation hubs, sewage treatment and landfills. As a result, desert dust lifts a growing load of airborne pollutants and transports these substances over long distances.
This is happening throughout the Global Dust Belt, an arid to semiarid region that stretches from western China through Central Asia, the Middle East and North Africa. Similar storms occur in the U.S. Southwest and central Australia.
To our thinking, modern desert dust storms have been overlooked as a public health crisis. Elevated exposure to these events is likely to contribute to rising respiratory and other diseases, including asthma and chronic obstructive pulmonary disease. We are environmental researchers whose work shows a need for better public health practices to protect people from dust storm pollutants.
To appreciate the scale of the threat, consider the Arabian Peninsula, where asthma rates have been the world’s highest for the past two decades.
In spring 2011, one of the most severe desert dust storms in recent decades swept across the Middle East at the peak of the dust storm season. Its plumes spread from the west coast of the Persian Gulf to the eastern shores of the Caspian Sea, covering northern Saudi Arabia, southern Iraq, Kuwait and western Iran. One quadrant of this large storm alone covered most of the Arabian Peninsula.
This storm reached vertically as high as 5.5 miles (9 kilometers) above the ground. Its wind speeds exceeded 45 mph (72 kilometers per hour) – higher than average wind speeds in the region. Dust particle concentrations peaked at 530,000 micrograms per cubic foot (15,000 micrograms per cubic meter), blocking sunlight for days.
One study found that a large proportion of individuals exposed to sandstorms had symptoms that included increased cough, runny nose, wheezing, acute asthmatic attack, eye irritation and redness, headache, sleep disturbance and psychological disturbances. Another study reported that increased dust storm exposure in western Iran led to increases in hospital admissions for chronic obstructive pulmonary disease and more deaths from respiratory causes.
Researchers study desert dust storms in a dozen different fields, each with its own terminology, expertise and body of knowledge. This work includes analyzing satellite images, creating simulation models for predicting dust particle transport, and identifying each dust storm’s particle content. So far, however, the health effects of desert dust storms and their changing particle content have gotten scant attention.
As we discussed in a recent review article, studies have found pollutants in dust storms that include bioreactive metals such as copper, chromium, nickel, lead and zinc, as well as pesticides, herbicides, radioactive particulates and aerosolized sewage. The extent to which desert dust storms transport a special class of pollution particles, those even smaller than one micron – or one millionth of a meter – is not yet clear.
...continued

Comments