Rare “Orange” air quality measured Sunday
Saharan dust is causing reduced air quality across the Southeast
ROANOKE, Va. (WDBJ) - You may have noticed the air over southwest Virginia looked a bit more hazy this weekend. Part of the reason is the increased moisture thanks to a humid air mass moving in. However, the haziness has been enhanced by the Saharan Air Layer (SAL), or dust, which has been moving from Africa and is now inundating the United States.
The Saharan dust has gotten close enough to the surface that a rare CODE ORANGE air quality forecast has been issued for Sunday (June 28). As of Sunday morning (at 10am), the local air sensors have measured Particulates at 106, which is just into the Orange level. A forecasted AQI level of 124 is expected today, which places it in the middle of Unhealthy for Sensitive Groups. This mean those with respiratory disease, such as asthma, should limit prolonged outdoor exertion until air quality improves, which should be Monday.
Any showers may wash some of the dust out of the skies, and in rare cases, may also leave a residue on objects after the raindrops evaporate.
WHAT ARE PARTICULATES?
The sand and dust known as Particulate Matter (PM) is composed of microscopic solids or liquid droplets that are so small they can be inhaled and cause serious health problems, especially those with existing breathing issues such as asthma. “Some of the particles are small enough to go deep into your lungs and even get into your bloodstream,” according to researchers with the Environmental Protection Agency, the government agency that monitors air quality around the Nation. Particles less than 2.5 micrometers in diameter, also known as “fine particles” or PM 2.5, pose the greatest risk to humans.
WHERE OUR AIR QUALITY IS MEASURED
There are several monitoring stations in Southwest and Central Virginia, but the closest certified air quality measurement device to the Roanoke metro is in Vinton at Herman L. Horn Elementary School. Additional devices are located in Rural Retreat and Natural Bridge.
While reporting criteria from the EPA may differ somewhat from that of Virginia DEQ, the most recent forecast for Code Orange air quality for Roanoke was recorded in May 2014. Before that you have to go back to 2008 and 2007 for Code Orange air quality measurements in the Roanoke area.
For decades, the main sources of the region’s air pollution had been coal-fired power plants and internal combustion engines – especially diesel engines that are older and had not been retrofitted to take advantage of the ultra low-sulfur diesel fuel.
Since the mid-2000s, a major initiative to bring attention to the importance of improving the region’s air quality has been underway and data shows it’s working. As vehicles become more efficient and power plants in nearby states become more “air friendly,” there have been hardly any “Orange” air quality days since 2010 and way fewer “Yellow” air quality days.
Those suffering with asthma and breathing issues know there’s a long way to go. Our mountain valleys trap the poor air until a large weather pattern shift occurs. That can sometimes be days. Then there are things totally out of our control, such as Saharan dust.
In a changing climate, we may be dealing with more dusty weather.
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