AIR DISPERSION MODELING
Advanced Air Quality Regulatory Compliance Through Precision Air Dispersion Modeling
✓ AERMOD, CALPUFF & ISCST3 regulatory modeling
✓ Toxic air pollutant (TAP) modeling
✓ Prevention of significant deterioration (PSD) modeling
✓ Clean Air Act permit application support
✓ Comprehensive source & emissions characterization
✓ Local, state & federal air quality compliance
✓ Customized modeling plans & results interpretation
✓ Pollution control & emission reduction strategies
✓ Integrated air quality monitoring & management
YEARS IN BUSINESS
COUNTRIES SERVED
STATES SERVED
CLIENTS SERVED
AIR QUALITY CONSULTING
What Is Air Dispersion Modeling?
Air dispersion modeling is a sophisticated computational process that predicts how pollutants emitted from industrial sources travel and concentrate in the surrounding atmosphere. By simulating how contaminants behave under real-world meteorological and terrain conditions, it gives industries, regulators, and developers the data they need to protect air quality and public health.
As certified air quality consultants, World Environmental uses dispersion modeling to evaluate emission sources, local meteorology, and terrain characteristics — then develops forward-thinking compliance strategies that minimize both environmental impact and operational cost.
Our models satisfy requirements set by the U.S. Environmental Protection Agency (EPA) under the Clean Air Act and its amendments, as well as state and local regulations across all 50 states.
Why Air Dispersion Modeling Matters
- Required for new air permits and facility modifications
- Predicts pollutant concentrations at receptor locations
- Demonstrates compliance with NAAQS and PSD increments
- Supports permit applications and regulatory submissions
- Informs pollution control and emission reduction strategies
AS SEEN ON
EPA-APPROVED METHODOLOGIES
Air Dispersion Modeling Regulatory Models
World Environmental is proficient in the full suite of EPA-mandated and EPA-recommended regulatory models. We select and apply the most appropriate model for each project’s specific regulatory context, terrain, and distance requirements — ensuring local, state, and federal compliance.
AERMOD Modeling
SHORT-RANGE · UP TO 50KM
The EPA's preferred regulatory model for most U.S. applications. AERMOD accounts for air turbulence, atmospheric stability, and terrain effects to produce detailed, reliable predictions of pollutant concentrations from stationary industrial sources. Required for the majority of new air permit applications.
CALPUFF Modeling
LONG-RANGE · COMPLEX TERRAIN
A non-steady-state Lagrangian puff model recommended for long-range pollutant transport and complex terrain situations. CALPUFF is essential for assessing cumulative impacts across large geographic areas and diverse meteorological conditions — critical for regional strategic planning and multi-source impact analysis.
ISCST3 Modeling
LEGACY APPLICATIONS
The Industrial Source Complex Short Term model remains applicable for historical data analysis and in specific jurisdictions where it continues to be a regulatory requirement. Our team maintains deep expertise in ISCST3 to support clients in these specialized regulatory contexts.
OUR APPROACH
How We Guide You Through Air Dispersion Modeling
Every modeling engagement follows a structured, transparent process designed to deliver defensible results while keeping you informed at every stage. Our guidance framework covers four critical phases:
1
Conducting the Modeling Study
Step-by-step project initiation: selecting the appropriate regulatory model, gathering emission source data, processing meteorological files, and executing simulations with full documentation of assumptions and inputs.
2
Interpreting Results
We translate complex model outputs into clear compliance demonstrations — explaining predicted concentrations in the context of applicable NAAQS, PSD increments, and ambient standards, accounting for local topography and meteorology.
3
Applying Findings
Modeling results inform concrete actions: pollution control system design, project scope modifications, mitigation recommendations, and strategic planning to ensure long-term compliance with minimal operational burden.
4
Navigating the Regulatory Process
We provide specialized guidance for state and federal regulatory submissions — coordinating with permitting agencies, responding to technical comments, and ensuring that modeling documentation meets all applicable guidance document requirements.
OUR SERVICES
Air Dispersion Modeling Services We Provide
Our modeling services cover the full lifecycle of regulatory compliance — from initial source characterization through permit submission and ongoing compliance support.
Toxic Air Pollutant (TAP) Modeling
TAP modeling is required for all new facilities seeking an air permit that emit toxic air pollutants, and for existing facilities modifying operations that may increase TAP emissions. Our analysis demonstrates compliance with ambient concentration limits to confirm that emissions do not pose unacceptable health risks to nearby communities.
Prevention of Significant Deterioration (PSD) Modeling
Facilities subject to PSD regulations must conduct dispersion modeling for PM2.5, PM10, SO2, NO2, lead, and CO. Our PSD analysis demonstrates that proposed emissions will not violate National Ambient Air Quality Standards (NAAQS) or exceed PSD increments — a requirement for new major sources and significant modifications at existing major facilities.
Clean Air Act Air Permit Support
We provide expert guidance throughout the air permitting process, from initial applicability determinations through modeling study design, report preparation, and regulatory agency coordination. Our permit support reduces application timelines and minimizes the risk of costly deficiency letters.
Source & Emissions Characterization
Accurate dispersion modeling starts with accurate emission inputs. We conduct comprehensive source characterization — including stack parameters, emission rates, operating schedules, and pollutant speciation — to ensure model inputs reflect actual facility conditions and produce defensible results.
Meteorological Data Processing
We process site-specific meteorological data from NWS stations, on-site monitoring networks, and model-derived datasets to develop representative hourly meteorological files for AERMOD, CALPUFF, and other regulatory models — a critical step in producing accurate, site-representative results.
Model Results Interpretation & Reporting
Our deliverables go beyond raw model outputs. We translate dispersion modeling results into clear, actionable compliance demonstrations — including receptor grid analyses, worst-case scenario assessments, and comparison with applicable standards — formatted to meet state and federal regulatory submission requirements.
What Our Clients Say…
OUR CLIENTS
Ready to Simplify Your Air Quality Compliance?
Speak with a World Environmental air quality consultant today. We’ll assess your needs and outline a clear path to compliance — no obligation, no jargon.