The following post is related to the Center’s work on a Health Impact Assessment of a proposed biomass-powered energy facility in the Shenandoah Valley of Virginia. The facility was proposed as a potential remedy to the issue of nutrient concentration related to trends in livestock production. Each post in the series describes one particular aspect of interest from the Center’s analysis.
Particulate Matter
Particulate Matter or PM refers to microscopic solids or liquids that are suspended in the air that we breathe. These particulates can come in various sizes but those less than 2.5µm in diameter (fine particulate matter or PM2.5) are of greatest concern because they can most easily pass through the airway, deep into the lungs, and possibly into the blood stream when they are inhaled. The U.S. Office of Management and Budget estimates that limiting the concentration of PM2.5 through federal regulation has a benefit of between $7 billion and $167 billion every year. Most of that comes from a decrease in mortality.
Fine Particulate Matter in the Valley
Recently, the U.S. Environmental Protection Agency (EPA) reduced that concentration of PM2.5 at which health is impacted from 15 µg/m3 to 12 µg/m3. In 2007, the concentration of PM2.5 in the Valley was above 12 µg/m3. Although this was, at the time, a legal concentration of PM2.5, the EPA now recognizes that some people in the Valley who are more vulnerable to poor air conditions (children, the elderly, those with respiratory or cardiac conditions) probably had worse health because it.
The concentration of PM2.5 in the Valley has improved since then but it has not been consistent. In 2009 and 2011, the concentration was between 9 and 10 µg/m3, a concentration considered safe even by more conservative estimates. However, in 2008 and 2010 the concentration was between 11 and 12 µg/m3, a concentration that although technically legal, is above more conservative estimates at which health is impacted and leaves little room for future development.
Fine Particulate Matter Formation From Agricultural Activities
Based on our air models, the facility would add less than 0.2 µg/m3 dependent on the location, not enough to drastically increase the risk in the Valley. However, the facility would also be adding some other air pollutants that are precursors to PM2.5 such as nitrogen oxides (NOx) and sulfur oxides (SOx). Ammonia in the atmosphere can react with one of these two pollutants to form PM2.5. Our air models suggest that the facility could add as much as 1.8 µg/m3 of NOx and 2.7 µg/m3 of SOx to the Valley atmosphere. The concentration of PM2.5 predicted by our air models probably is not enough to impact health if the PM2.5 concentration is low to begin with. However, the concentration that is already in the Valley is probably high enough to justify increased scrutiny before bringing another source of pollution to the Valley.