AIR DISPERSION MODELING

The monitoring of industrial emissions to the atmosphere is changing rapidly in response to increased demands from regulators. Hardware, software and application techniques have all evolved.   Keeping current with developments is a continual challenge. 

Research continues to show that airborne contaminants can be carried hundreds of miles from its source and can cause health and environmental problems on a regional or even global scale. In humans, airborne contaminants can cause burning eyes, irritated throats, difficulty with breathing, long-term damage to the respiratory and reproductive systems, cancer, and, in the most severe cases, death.   Trees, lakes, crops, buildings, and statues can be damaged by air pollution.

In the USA, the Clean Air Act of 1970 (amended in 1990), administered by the U.S. Environmental Protection Agency (EPA) sets and enforces air pollutant limits on sources such as power plants and industrial facilities to help protect against harmful health and environmental effects. Although the Clean Air Act is a Federal law, state and local agencies are responsible for implementing many of its requirements.   Other countries with air pollution problems have put into place similar laws, directives, and initiates.

Airborne contaminants such as sulfur dioxide, particulate matter, ozone emitted by industrial facilities can travel great distances from their sources.   Airborne contaminants migrate across political boundaries and states (and provinces) and communities cannot independently solve all of their air contamination problems.   Resolving air pollution control issues often requires state (and provincial or regional) and local governments to work together to reduce air emissions.

Evaluation of Industrial Air Pollution

To evaluate air pollution, the air must either be sampled and tested with real-time field instrumentation, onsite laboratory analysis, or by the collection of air samples for laboratory analysis.   The evaluation of industrial air contaminant plumes is complex because contaminant concentrations vary with time, distance from source, and with meteorological conditions.  

Air Dispersion Modeling Software

Geologic Resources is a reseller of Breeze air dispersion, hazardous gas dispersion, explosion, and fire modeling software.   We also list links to a number of sources of geologic, scientific, and environmental software on our internet software links page.   Some Breeze software that can assist with compliance, monitoring, and assessment include:

• Breeze SCREEN3 software is also unique among EPA models because it can incorporate the effects of inversion break-up and shoreline fumigation.

• Breeze DEGADIS software is ideal for determining toxic endpoint distances and distances to lower flammability limits (LFLs) for certain toxic and flammable chemicals in accordance with EPA’s Risk Management Program (RMP) requirements.
• Breeze SLAB softare is ideal for determining toxic endpoint distances and distances to lower flammability limits (LFLs) for certain toxic and flammable chemicals in accordance with EPA’s Risk Management Program (RMP) requirements.
• Breeze INPUFF software is an integrated Gaussian puff model developed by the U.S. EPA to model buoyant or neutrally buoyant gas releases from a stack. The release duration can be specified as either finite or continuous. Source types include stacks and surface-based releases.
• The algorithms contained in the BREEZE HAZ EXPERT are based primarily on EPA’s document, “Guidance on the Application of Refined Dispersion Models to Hazardous/Toxic Air Pollutant Releases.