Air Dispersion Modeling


Air dispersion modeling provides a sophisticated tool for predicting the trajectory and concentration of pollutants emitted into the atmosphere. This service is critical in assessing environmental impacts, facilitating compliance with air quality regulations, and designing strategies for pollution reduction.

By simulating how various pollutants disperse and react under specific atmospheric conditions, our air dispersion modeling provides industries, developers, and policymakers with the insights needed to make informed decisions about environmental protection and public health.

As air quality consultants, we are committed to creating and implementing creative solutions that allow our clients to maximize efficiency while maintaining compliance.

The Clean Air Act (CAA) and its subsequent amendments, along with the regulations implemented by the EPA, serve as a fundamental framework for safeguarding human health and the environment in relation to air quality concerns. These federal laws and regulations, coupled with state and local regulations, are subject to periodic updates as the United States strives to strike a balance between economic and environmental considerations.

Furthermore, in developing a comprehensive strategy for air permitting and regulatory compliance, it is crucial to account for each of these regulatory requirements. Air quality consultants play a pivotal role in assisting organizations to navigate these intricate regulations and ensure ongoing compliance.

Air Dispersion Modeling Regulatory Models

World Environmental remains at the forefront of regulatory compliance and technological sophistication in air dispersion modeling. Our firm is well-versed in a comprehensive suite of regulatory models mandated or recommended for various industries and applications. Understanding the intricate requirements of each regulatory context, we select and apply the most appropriate models to ensure that our clients’ projects comply with all local, national, and international air quality regulations.

Our expertise encompasses a broad range of regulatory models, each with its specific applications, strengths, and limitations. These include:


As the preferred model for most regulatory applications in the United States, AERMOD is designed for short-range (up to 50km) dispersion of pollutants from stationary industrial sources. It incorporates air turbulence and terrain effects, providing detailed and reliable predictions of pollutant concentrations.


For long-range transport and complex terrain situations, CALPUFF offers a versatile solution. This non-steady-state model is recommended for assessing the impact of pollutants over large distances and diverse meteorological conditions, making it crucial for strategic planning and impact analysis.


The Industrial Source Complex Short Term model, though older, is still used in specific scenarios, particularly for historical data analysis or in regions where it remains a regulatory requirement.

Toxic Air Pollutant (TAP) Modeling

Toxic air pollutants are a major concern due to their potential to cause severe health issues, including cancer, as well as adverse environmental effects. TAP modeling is an essential requirement for all new facilities needing an air permit and those emitting toxic air pollutants. It’s also necessary for existing facilities undergoing modifications that may increase emissions of TAPs. Our goal through TAP modeling is to demonstrate compliance with established ambient concentration limits, ensuring that emissions do not adversely affect ambient air quality standards.

Prevention of SIgnificant Deterioration (PSD) Modeling

Facilities subject to Prevention of Significant Deterioration (PSD) regulations must undertake air dispersion modeling to adhere to strict environmental standards. This includes new major sources of PSD and significant modifications at existing PSD major sources. The air quality analysis conducted aims to demonstrate that the emissions from the proposed project will not violate the National Ambient Air Quality Standards (NAAQS) or exceed PSD increments. Specifically, air dispersion modeling under PSD regulations is mandated for pollutants including PM2.5, PM10, SO2, NO2, Pb, and CO. Our approach ensures that projects not only comply with regulatory requirements but also contribute to the protection and improvement of air quality.

At World Environmental, our commitment to regulatory excellence means that clients receive sophisticated, compliant, and effective dispersion modeling services tailored to their specific needs. Whether navigating the complexities of a new construction project, expanding industrial operations, or implementing environmental health strategies, our clients rely on us to deliver top-tier modeling solutions that align with the strictest regulatory standards.

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“World Environmental’s commitment to client success is truly commendable. They took the time to understand our unique needs and provided tailored solutions that aligned perfectly with our goals.”

– J.D.

Guidance Documents for Effective DIspersion Modeling

At World Environmental, we believe that empowering our clients with knowledge and tools is crucial for successful environmental management. Our suite of guidance documents serves as a comprehensive resource for conducting air dispersion modeling, interpreting results, and applying findings effectively across various regulatory and planning scenarios.

Conducting Dispersion Modeling

Our guidance begins with a detailed overview of the modeling process, tailored to the specific needs and contexts of our clients’ projects. We provide step-by-step instructions on initiating a modeling study, from selecting the appropriate model and gathering necessary data to running simulations and analyzing outputs. This ensures that our clients understand the process, implications, and requirements of their modeling endeavors.

Interpreting Results

Understanding the results of dispersion modeling is vital for informed decision-making. Our documents demystify complex data, translating it into clear, actionable insights. We guide clients through the interpretation of model outputs, discussing what the concentrations mean for their project, the environment, and public health. Our emphasis is on providing a nuanced understanding of the results, considering local topography, meteorological conditions, and other site-specific factors.

Applying Findings

The ultimate goal of dispersion modeling is to inform and guide actions. Whether it’s for regulatory compliance, environmental impact assessment, or public health protection, our guidance documents outline strategies for applying modeling findings. This includes recommendations for pollution control, project modification, and strategic planning, ensuring that our clients can make the most of their modeling results.

Navigating Regulatory and Planning Scenarios

Every project exists within a specific regulatory and planning context. Our guidance documents are customized to address these contexts, offering specialized advice for navigating the regulatory process, adhering to environmental standards, and achieving project objectives. Whether the concern is local zoning, national air quality standards, or international environmental agreements, our resources provide the clarity and direction needed to move forward confidently.

At World Environmental, our guidance documents are more than just manuals; they are a reflection of our commitment to client success and environmental stewardship. By equipping our clients with these detailed guides, we empower them to participate actively in the modeling process, understand the implications of their projects, and make informed decisions that lead to sustainable, compliant outcomes.

Air Dispersion Modeling at World Environmental

When you choose World Environmental for your air dispersion modeling needs, you are selecting a partner dedicated to excellence, precision, and innovation. Our firm offers a unique blend of scientific rigor, regulatory expertise, and a deep commitment to environmental stewardship. The benefits of working with us include:

Comprehensive Expertise

Our team possesses extensive knowledge and experience in air quality and dispersion modeling, ensuring that your project meets all regulatory requirements and environmental goals.

Customized Solutions

We understand that each client has unique needs. Our approach is tailored to provide solutions that fit your specific project requirements, delivering accurate, actionable results.

Technological Leadership

Leveraging the latest in modeling technology and staying abreast of technical advancements, we offer services that represent the forefront of environmental science.

Commitment to Sustainability

Our work is guided by a commitment to creating a healthier, more sustainable future. We strive to minimize environmental impacts and help our clients achieve their sustainability goals.

Contact World Environmental today to learn more about our services and how we can assist you in achieving project success while upholding environmental integrity. Our team is ready to provide the insights and guidance you need to navigate the complexities of air dispersion modeling.

Breathe easier knowing that your environmental responsibilities are in capable hands. Reach out to World Environmental now and take the first step towards a clearer, cleaner future.