understanding the role of air quality modeling in environmental compliance
TRANSCRIPT
www.all4inc.com Philadelphia | 610.933.5246
Atlanta | 678.460.0324 Houston | 281.937.7553
Understanding the Role of Air Quality Modeling in
Environmental Compliance
Mark Wenclawiak, CCM| [email protected] | 678-460-0324 February 10, 2015
Presented to The American Society of Safety Engineers Augusta/Aiken Chapter
by All4 Inc.
2 Your environmental compliance is clearly our business.
Agenda What are air quality models? Why do we perform air quality modeling? What goes into an air quality model? Questions and answers
3 Your environmental compliance is clearly our business.
ALL4 Environmental consulting firm Founded 2002 – currently 40+ employees Offices in Philadelphia, Atlanta, Houston Specialize in air quality consulting
• Complex air permitting and strategy development • Air dispersion modeling • Ambient air quality monitoring
Dispersion modeling as a company-wide initiative www.all4inc.com
6 Your environmental compliance is clearly our business.
Air Quality Models Models are predictive tools
• Past performance is not a predictor of future results
Mathematical and numerical techniques to simulate the physical and chemical processes that affect air pollutants as they disperse and react in the atmosphere • Conservative assumptions
8 Your environmental compliance is clearly our business.
Models and the Real World… Speaking of complex…how do you model this?
9 Your environmental compliance is clearly our business.
Types of Air Quality Models Screening Refined Photochemical Long-range transport Mobile sources U.S. EPA’s preferred/recommended models
• 40 CFR Part 51, Appendix W
11 Your environmental compliance is clearly our business.
Support air permit applications • Construction projects • GEPD and SCDHEC air toxics analyses
Conduct risk assessments • Human health and environmental impacts
Play detective (forensics evaluations) • Nuisance dusts and odor complaints
Proactively evaluate compliance • Facility expansions • Preparing for upcoming regulations
Modeling is Performed to…
13 Your environmental compliance is clearly our business.
Emissions information Meteorological data Building dimensions Topography Agency-approved protocol
Data Input
14 Your environmental compliance is clearly our business.
Data Input Hourly Data Wind Speed
Wind Direction Ambient Temperature
Land Use Patterns Topography
Building Dimensions Stack Dimensions Exhaust Velocity
Exhaust Temperature Emission Rates
Predicted Ground Level Ambient
Concentrations
Beware – Garbage In, Garbage Out!
15 Your environmental compliance is clearly our business.
Short-term emission rates Exhaust (stack) characteristics May or may not be readily available
Emissions Information
16 Your environmental compliance is clearly our business.
Surface data and upper air data National Weather Service or on-site data
• Not your Sky Mall weather station
Meteorological Data
19 Your environmental compliance is clearly our business.
Meteorological Data
AERMOD Interface
Vertical profiles of wind speed Lateral and vertical turbulent fluctuations
Potential temperature gradient Potential temperature
AERMET
Albedo Surface Roughness
Bowen Ratio
Surface Characteristics
Calculates
Gaussian Equation for Estimating Dispersion
Wind Speed Wind Direction Temperature Cloud Cover
Meteorological Observations
Friction Velocity Monin-Obukhov Length
Convective Velocity Scale Temperature Scale
Mixing Height Surface Heat Flux
Planetary Boundary Layer Parameters
20 Your environmental compliance is clearly our business.
Horizontal dimensions Building height
• Tiers
Building Dimensions
23 Your environmental compliance is clearly our business.
Terrain elevation Land use From these, develop a receptor grid
• Exclude onsite receptors
Topography
24 Your environmental compliance is clearly our business.
Typical receptor grid spacing: • 100 meters out to 2 kilometers • 200 meters out to 5 kilometers • 500 meters out to 10 kilometers • 25 meter spacing along fenceline, assuming that only
offsite receptors are being modeled
Public access must be restricted in some way (e.g., fence, armed guards, attack dogs, moat) in order for onsite receptors to be disregarded in the modeling analysis
Receptor Grid
26 Your environmental compliance is clearly our business.
Don’t Forget Background Data!
188
NO
2 1-h
our C
once
ntra
tion
(µg/
m3 )
80
NAAQS Level
Monitored Background Value
108 µg/m3 available for modeling
27 Your environmental compliance is clearly our business.
All4 Inc. GEPD
• http://www.georgiaair.org/airpermit/html/sspp/modeling.htm
SCDHEC • http://www.scdhec.gov/Environment/AirQuality/Com
plianceandReporting/AirDispersionModeling/
U.S • http://www.epa.gov/scram001/
Resources and Guidance