Air Quality Investigation: Air Modeling
A second type of data that ATSDR is analyzing comes from air dispersion modeling. Data that comes from air modeling differ from air monitoring data. Air modeling estimates the level of chemicals in air, whereas air monitors measure the actual levels of chemicals in the air. A model uses mathematical formulas to estimate how weather, wind, and land elevations transport or remove an airborne chemical. Models predict the amount of a chemical at locations downwind (that is, in the direction the wind is blowing) from the pollution source.
In 2004, ATSDR used a model called CALPUFF to estimate the chemical levels to which the community was exposed. The model also predicted where the concentrations of chemicals are the highest and the lowest. To do this, the four facilities in the former Union Carbide complex and AMP Ohio (across the street) provided site-specific data for the chemicals they released. Using this information, nine chemicals were identified for modeling: chlorobenzene, chloromethane, styrene, toluene, hydrochloric acid, sulfuric acid, ammonia, chromium, and manganese.
Manganese Air Dispersion Map
The models estimated that, in some areas, airborne manganese levels are higher than normal. The other eight chemicals modeled were found to be typical of background levels in the United States.
ATSDR used air dispersion models to select the new 2007 air monitor locations. Although the air investigation started in Washington County, Ohio, air monitoring confirms that Wood County, West Virginia may be affected as well.
Results from air sampling in the Mid-Ohio Valley are summarized in the newsletters linked below. We will add results quarterly to the Web site:
- Marietta Air Emissions Newsletter 1 [PDF - 523 KB]
Air investigation April—June 2007 Results
- Marietta Air Emissions Newsletter 2 [PDF - 426 KB]
Air investigation July—September 2007 Results
- Marietta Air Emissions Newsletter 3 [PDF - 426 KB]
Air investigation October—December 2007 Results