Monitoring

Monitoring can include everything from continuous emission monitoring (CEM) to keeping records of complaints received. Monitoring can be quite expensive. Even if the equipment used for monitoring is not expensive, there is always a frequency of monitoring that must be met, and doing the monitoring takes staff resources that, for a large facility, can be… Continue reading Monitoring

CALPUFF

CALPUFF is an advanced, integrated Lagrangian puff modeling system for the simulation of atmospheric pollution dispersion (Code of Federal Register, 40 CFD). The model has been adopted by the USEPA in its Guideline on Air Quality Models as a preferred model for assessing long‐range transport of pollutants and their impacts on Federal Class I areas and on… Continue reading CALPUFF

Dispersion Models: Indoor Concentrations

Diffusion of contaminants in workplace air results in the net movement of the contaminants from regions of higher concentration to regions of lower concentration. The spread of the contaminant is aided by the advective mass transfer driven by the ventilation system. The combination of these influences results in movement of contaminants away from their source… Continue reading Dispersion Models: Indoor Concentrations

Atmospheric Layers

Discussion of the layers in the Earth’s atmosphere is needed to understand where airborne pollutants disperse in the atmosphere. The layer closest to the Earth’s surface is known as the troposphere. It extends from sea‐level to a height of about 18 km and contains about 80% of the mass of the overall atmosphere. The stratosphere is the next layer… Continue reading Atmospheric Layers

Atmospheric Dispersion Modeling

Atmospheric dispersion modeling is the mathematical simulation of how air pollutants disperse in the ambient atmosphere. It is performed with computer programs that include algorithms to solve the mathematical equations that govern the pollutant dispersion. The dispersion models are used to estimate the downwind ambient concentration of air pollutants or toxins emitted from sources such… Continue reading Atmospheric Dispersion Modeling

Evaluate Impacts of Technology

The next step in the “top‐down” process is to determine whether there are energy, environmental, or cost impacts from the use of this top technology that would render it infeasible. Energy Impacts Energy impacts include the energy consumed by the control technology or a reduction in energy produced, if an energy‐production process is permitted. One… Continue reading Evaluate Impacts of Technology

BACT Selection Strategy

Most jurisdictions require that BACT be used in all new or modified sources. The regulations seldom specify how to determine BACT beyond defining the term. In Section 4.14.4, the “top‐down” approach developed by EPA for formal determination of BACT is described. The “top‐down” process is thorough, sequential, and complete. However, it can be expensive to conduct… Continue reading BACT Selection Strategy