Air Quality Modeling
Why do we do air quality modeling?
The Baltimore region does not currently meet federal air quality standards for ozone and fine particulates. As a result, the region is required to estimate future air pollution emissions that will result from projects in the Baltimore Regional Long Range Transportation Plan and the Transportation Improvement Program.
Through air quality modeling, we can determine the potential impact that highway and transit projects in transportation plans and programs will have on our air quality.*
In addition, this modeling process ensures that regional transportation plans do not delay the timely attainment of federal air quality standards. This process is called a conformity determination. To learn more about conformity determinations, visit our page on Air Quality Conformity
How is air quality modeling performed?
Emissions that result from transportation projects in the Baltimore region are estimated using a computer model.** After Baltimore Metropolitan Council staff runs the travel demand model to determine demand on the region’s transportation system in future years, air pollution emissions modeling is performed.
Travel demand estimates from the region’s travel demand model are combined with environmental assumptions (such as temperature) and information on mobile emissions control programs (such as inspection and maintenance programs) to become inputs to the air quality model. Then, the air quality model is run and outputs data that is then converted into estimates of air pollutant emissions.
This process provides estimates of emissions of nitrogen oxides, volatile organic compounds, and carbon monoxide (in tons per day) as well as fine particulates, or fine soot (in tons per year), resulting from the region’s transportation system.
Which BMC committees are responsible for air quality modeling?
The Interagency Consultation Group is the committee that focuses on air quality issues. It is responsible for coordinating the transportation conformity process, and overseeing the air quality modeling process. The Technical Committee is responsible for reviewing all technical analyses associated with conformity, such as modeling assumptions, data collection and accuracy.
For more information on Environmental Protection Agency's air quality model for vehicle emissions, called the MOBILE emissions model, visit: http://www.epa.gov/otaq/mobile.htm.
* The Clean Air Act Amendments of 1990 require that regions that are not reaching federal standards for air quality must test transportation plans and programs to make sure that their air quality is not made worse by their implementation.
** The U.S. Environmental Protection Agency has procedures for calculating air emissions estimates in future years. BMC maintains an air quality modeling process that meets the EPA’s requirements.
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