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Fugitive dust is an environmental air quality term for very small suspended in the air, primarily mineral dust that is sourced from the soil of Earth's pedosphere. A significant volume of fugitive dust that is visible from a distance is known as a dust cloud, and a large dust cloud driven by a gust front is known as a dust storm.
Fugitive dust particles are mainly minerals common to soil, including , aluminium oxide, calcium carbonates and . About half of fugitive dust particles are larger than 10 in particle size and settle more quickly than the smaller particles. It does not include particulates from other common artificial sources such as vehicle exhaust, or . The term is used to denote that the dust "escapes" into the atmosphere rather than being exhausted in a "confined flow stream" from a "ducted emitter" (an exhaust pipe or chimney).
The U.S. Environmental Protection Agency estimated that fugitive dust was responsible for 92% of the PM-10 emissions in the United States in 1995.
Surfaces susceptible to fugitive dust emissions are both natural and man-made. Specific sources include open fields and parking lots, paved and unpaved roads, agricultural fields, construction sites, unenclosed storage piles, and material transfer systems. Surface mining operations are also sources of fugitive dust as a result of many mining operations including , tailings piles, drilling, blasting, the removal of overburden and the actual mineral extraction.
In 1995, 28 percent of fugitive dust in the US originated from unpaved roads, 23 percent from construction sites, 19 percent agricultural, 15 percent from paved roads, 5 percent from wind erosion, 1 percent from mining according to the EPA.
In addition to outdoor dust sources, numerous indoor dust sources also exist, often in manufacturing and similar industries. Examples of this include the metalworking process which incorporates different forms of grinding, cutting, and polishing, various food industries like sugar, spices, and grains, and even the pharmaceutical industry during packaging or production. In order to reduce the possibility of different hazards brought upon by indoor fugitive dusts, prevention must be a top priority.
There are two general kinds of hazards associated with airborne dusts- combustible dust scenarios and health effects.
Dust explosion incidents primarily occur in two separate stages. The initial deflagration usually takes place within machinery or an enclosed area. This can disturb dust which has settled or damage surrounding equipment. The second explosion then has the potential to be far more destructive since more dust is dispersed and ready to ignite.
Examples of combustible dust disasters include:
As wind-borne dust can easily migrate, respiratory irritation can occur in construction and agricultural workers close to a source as well as others including wildlife. In addition to adverse health effects, the abrasive nature of particulate matter can cause property damage and obscure visibility leading to vehicular collisions causing injury and death.
Fugitive dust can also harm plant life. In 1999, the National Park Service found that lichen and other non-vascular plants in the Cape Krusenstern National Monument in Alaska were affected due to dust generated from hauling ore from the Red Dog mine along a road within the monument. A follow-up study in 2006 found slightly elevated levels of lead and cadmium concentrations in small birds and voles captured along the road.
A lawsuit in 2011 filed by 150 Waimea, Hawaii residents alleges that their homes were subjected, "on almost a daily basis", to blown "pesticide-laden fugitive dust". The residents claimed their homes sustained physical damage and they were forced to live with their windows closed year-round. They were seeking monetary damages from DuPont Pioneer to compensate for the reduced value of their homes and suggested future lawsuits would address health issues.
A 2017 lawsuit in Maryland claims that fugitive dust from a -high pile of coal dust at a coal processing plant has caused "extensive damage" through erosion to blades on in a nearby wind farm.
Fugitive dust can be controlled by the application of various chemical suppressants including , petroleum resins, , salts, plastics, and wetting agents.
Coal dust piles have been treated with water or other chemical to suppress dust until the moisture evaporates. Other chemicals can provide protection for up to six months. Wind fences of polyester fabric can also be used to slow wind movement and minimize fugitive dust.
For indoor sources, effective prevention methods consist of inspections and material transfer isolation. Implementing a thorough schedule of inspecting locations of potential dust build up and procedures for cleaning these surfaces can limit high accumulations of dust. Enclosing conveyor belts and providing proper dust collection measures will reduce leakage and control dispersion.
The US Federal Environmental Protection Agency has specific standards for daily average particulate matter originating from active mines. Finer particulates have been detected up to from mining operations.
Fugitive dust acquires an electrostatic charge when dispersed in the air. Spraying an oppositely charged water fog can be used to effectively control dust in an industrial setting. If so charged, less water is needed to cause the particulate matter to drop from the air. This method has been tested with many materials including silica flour, sulfur dioxide, and fly ash.
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