I spoke with a man recently who called our office wanting to know about dust: how to stop it and what sort of regulations cover the activities that generate it. Several large, long-term construction projects are underway in his neighborhood, and he described how he has repeatedly cleaned his carpets and drapes as the onslaught continues, drained his swimming pool, and even tried to vacuum out dust embedded in the porous tiles in his house.Annoying? Of course, and new evidence suggests dust could even be more dangerous than anyone previously realized. Airborne dust has long been associated with respiratory illness; in June, the Journal of the American Heart Association reported on a Boston study correlating hospital emergency-room data with air-quality data. As the concentration of PM2.5 particles (those less than 2.5 microns in diameter, which are thought to escape the lung¹s filtering mechanisms) increased, so did the number of heart attacks. Work is ongoing to determine whether specific types of particles raise the risk more than others or whether size alone is the critical factor.
Rapidly growing cities with many unpaved roads and much construction—Las Vegas and Phoenix are often cited as prime examples—have been grappling for years with the health, safety, economic, and legal implications of dust, as well as with the annoyance factor. Various EPA regions are developing new rules, supplementing whatever local air-quality regulations are in place. These often involve using organic or chemical dust suppressants and soil stabilizers, graveling unpaved lots, reducing exposed areas susceptible to wind erosion on construction sites and other workplaces, and limiting dust-generating activities on especially windy days.
The problem with local controls is that dust travels. At least the man with the sandy swimming pool and silt-filled tiles can identify the source of his problem—it’s right down the street—and the possible recourse. But the origin isn’t always simple or localized, and the haze you see out your window today might have a far more distant source. Large dust clouds originating in China hovered over the Rocky Mountains earlier this year, blotting out the mountains entirely in some places. Dust from Northern Africa has reached the Caribbean and the Southeastern US.
China¹s dust problem is especially severe and growing. In May, Reuters published dramatic photos of pedestrians and bicyclists on a street in the central Chinese city of Chengdu, some with their faces buried in their hands and others bent double to shield themselves from a violent dust storm blowing through the downtown area. It¹s a dilemma not only within the country but also for neighbors like Japan and South Korea, which are now working with China on the issue, and increasingly for more distant countries.Causes vary. During the Cultural Revolution, China’s government sought to eliminate “Western” influenced landscape features such as lawns—although existing vegetation had been killed to establish the lawns in the first place, and the new practice left huge tracts of exposed soil. More widespread culprits today are drought, deforestation, overgrazing, overploughing, and poor irrigation practices that lower water tables and dry up rivers and lakes. By some estimates, 900 square miles of China’s land experiences severe wind erosion each year, and far more is deteriorating.
In the US, the proliferation of local and regional regs mean possible new constraints for builders and new opportunities for those who deal in controlling dust. But the global problem means people everywhere who are responsible for air quality—and water quality, in some cases, as airborne dust and pollutants settle and are washed into surface waters—face a problem over which they have no possible jurisdiction.
