Christopher DesAutels
Christopher DesAutels
Managing Scientist
Health Sciences
Maynard

Mr. DesAutels has nearly 20 years of experience simulating the transport of air pollutants and conducting air quality modeling studies. He is active in applying air dispersion models, including AERMOD, CALPUFF, Computational Fluid Dynamics (CFD), and dense gas models, to complex dispersion problems in support for both regulatory permitting applications and litigation. As the current lead scientist and software developer for the CALPUFF model he coordinates enhancements and bug fixes to the model code. Recent development work includes the implementation of a new CALPUFF source type in order to model aerial spraying, and linking CALPUFF with the agricultural spray model AGDISP.

Mr. DesAutels also has an active interest in air impacts due to transportation. He has developed programs to calculate air emissions for mobile sources and to properly account for fleet composition age and vehicle turnover times. These have been applied to calculate mobile vehicle emissions inventories internationally, including in Saudi Arabia and Bahrain. He has also applied CFD to investigate the accidental release of dense gases resulting from the breach of pressurized vessels during rail and trucking accidents.

Mr. DesAutels has conducted numerous CFD modeling studies to understand atmospheric flows and dispersion in complex situations. These have included accidental spills of flashing and dense gases during rail, transportation, and industrial accidents, cooling tower plume re-circulation, building damage from hurricane force wind speeds, and wind energy applications. Mr. DesAutels is experienced in the use of the FLUENT and Star-CCM+ models for atmospheric modeling and has also conducted studies using the OpenFOAM CFD platform. He has performed evaluation work of CFD air dispersion modeling techniques including comparisons of field data sets and CFD simulations for large-scale releases of ammonia and hydrogen sulfide.

Mr. DesAutels is experienced in system administration and configuration of Linux high power multi-processor computing systems and programming in both FORTRAN and Perl for manipulating and evaluating large data sets. Mr. DesAutels also has experience with the field operation of SODAR systems and evaluation of collected meteorological datasets.

CREDENTIALS & PROFESSIONAL HONORS

  • M.S., Geosystems, Massachusetts Institute of Technology (MIT), 2000
  • B.A., Physics, University of Pennsylvania, 1997
  • B.A., Geology, University of Pennsylvania, 1997

Publications

Strimaitis DG, Scire JS, DesAutels C, Popovic J. Roadway Module in CALPUFF Version 7. Air & Waste Management Association 108th Annual Meeting, Raleigh, NC, June 2015.

Schulman LL, DesAutels CG, Kolts B. Effectiveness of wind fences to reduce fugitive particulate emissions from material piles: A computational fluid dynamics study. Air & Waste Management Association 106th Annual Meeting, Chicago, IL, June 2013.

Schulman LL, DesAutels CG. Comparing AERMOD and CFD downwash predictions for GEP stacks. Guideline on Air Quality Models: The Path Forward Conference, Raleigh, NC, March 2013.

Ponchaut NF, Kytömaa HK, DesAutels C, Kaganoi S, Becu O, Cardiff G. Modeling of ground flare pits. AIChE Spring Meeting, 12th Topical Conference on Gas Utilization, Houston, TX, April 2012.

Richter RO, Schulman LL, DesAutels CG. Estimating exposure concentrations for trench workers from vapors emanating from soils and groundwater using computational fluid dynamics modeling. Society of Risk Analysis Annual Meeting, San Francisco, CA, 2012.

DesAutels, CG, Schulman, LL. Evaluation of the desert tortoise ammonia field tests with the FLUENT CFD model using unsteady RANS, 5th International Symposium on Wind Engineering, Chapel Hill, NC, 2010.

Schulman LL, DesAutels CG, Viti V. CFD simulations to predict wind induced damage to a steel building during Hurricane Katrina. 5th International Symposium on Computational Wind Engineering, Chapel Hill, NC, May 2010.

Schulman LL, DesAutels CG. Estimating the effect of building wakes on wind power generation using the CFD model FLUENT. EUEC Energy and Environment Conference, Phoenix, AZ, February 2009.

Schulman LL, DesAutels CG. CFD simulation of building downwash in the EPA wind tunnel. Air & Waste Management Association 101st Annual Meeting, Portland, OR, June 2008.

Emanuel K, DesAutels C, Holloway C, Korty R. Environmental control of tropical cyclone intensity. Journal of the Atmospheric Sciences, April 2004.

Prior Experience

Senior Meteorologist, TRC Corporations, 2006–2011

Meteorologist, Earth Tech, 2000–2005

Senior Associate Engineer, Raytheon, 1997–1999

Project Experience

Transportation Emissions Calculations and Modeling

CEQA Air Quality Modeling Support – California

Provided support and review of an air quality model evaluation for a proposed railyard as part of a California Environmental Quality Act (CEQA) Environmental Impact Report.

Air Quality Modeling Study - Bahrain

Performed air emissions inventory tasks to quantify the impacts of both present and future mobile and stationary sources. This included the development of FORTRAN code to track mobile emissions growth, the mobile fleet composition and mobile emission factors over a 30 year period. Performed CALPUFF modeling to predict countrywide impacts and validated the model results against air quality databases. Suggestions were provided to the client on how to minimize future impacts to assist with future planning. CALGRID photochemical modeling was also performed to evaluate local and regional ozone impacts.

Mobile Fuel Study - Jeddah, Makkah, and Riyadh, Saudi Arabia

Conducted an air quality modeling study, which evaluated the air quality impact of various mobile fuel options for the urban areas around Jeddah, Makkah and Riyadh Saudi Arabia. This study looked both at emission changes due to different fuels, and at the impact that future population growth will have on the urban air quality. Work included the development of a mobile emissions database, modeling using the CALPUFF system, and validation of the modeling results against monitored air quality data. Modeled pollutants included SO2, NOx, PM10, CO and Benzene.

Urban Tunnel Air Modeling Study

Developed a FORTRAN program in order to determine dilution factors for emissions from roadway tunnel portals. The program output was used to determine emission limits for the roadway tunnels.

CFD Dense Gas Modeling

Vinyl Chloride Release – New Jersey


Produced CFD modeling of a vinyl chloride release from a breached railcar. Modeling was used as part of an expert report submitted during litigation. Mr. DesAutels was also deposed on the modeling performed as part of litigation the process.

H2S Modeling Study - Saudi Arabia


Conducted CFD modeling of potential H2S releases at a Gas Oil Separation Plant. Releases included dry evaporation ponds, water filled ponds and venting from storage tanks. The same releases were also evaluated using the dense gas model HGSYSTEMS. Results of different release scenarios were compared to determine risk.

CFD Modeling of NH3 Releases


Conducted multiphase CFD modeling for both aqueous and anhydrous ammonia releases from railcars. These releases included both ground based pools and cold, heavier than air multiphase flows resulting from flashing of pressurized NH3. Discrete phase modeling was used to track both liquid and gaseous phases. Modeled results were used for transportation planning purposes and risk assessment.

CFD Building and Structure Wind Loading Modeling

Wind Damage Modeling – Litigation

Performed CFD modeling for multiple cases to estimate wind loading on industrial and residential buildings during severe weather events in support of wind damage litigation cases. Multiple cases involved impacts due to winds during Hurricane Katrina.

Offshore Platform Wind Loading


Performed CFD modeling for off-shore platforms to calculate forces and moments. Compared model results with previously performed wind tunnel studies to evaluate CFD model performance. CFD modeling has been proposed as a tool to be used during the platform design process.

CFD Ventilation and Circulation Modeling

Analysis of Cooling Tower Recirculation

Conducted CFD modeling to evaluate mitigation strategies to minimize recirculation within an array of cooling towers. Strategies investigated included repositioning towers and changes to the tower structures.

Turbine Siting Studies

CFD modeling was performed to aid in the proper siting of wind turbines. Rooftop wind turbines were investigated for a museum installation where results of the modeling are also used for educational purposes at the museum. Modeling was also conducted to investigate the impacts of a proposed building on a free-standing downwind turbine.

Dust Control Modeling

Performed CFD modeling to evaluate the impacts of wind breaks on dust emissions from coal storage piles at a power plant. Evaluation included simulations of different fence porosities and geometries.

Modeling of an Air Cooled Condenser


CFD modeling was performed for odor emissions from an air cooled condenser located at a geothermal power plant. CFD modeling was used to determine the proper source term for modeling using CALPUFF.

Regional Air Quality Modeling

Residential Wood burning Modeling – British Columbia Canada


Calculated particulate emissions due to residential wood burning and spatially allocated those emissions based on publicly available data as part of a regional air shed modeling study. The modeling study evaluated the total air burden from wood burning and other regional sources as part of an air quality planning study.

Regional Air Quality Modeling - Saudi Arabia


Mr. DesAutels performed regional modeling studies for both the east coast and west coast of Saudi Arabia. These studies included impacts from both local and long range sources of SO2, NOx and PM10. Modeled sources included power plants, desalination plants, petroleum production facilities, mobile sources and other industrial sources of emissions.

Power Plant Emission Study - Saudi Arabia

Performed air quality modeling of Power Plants at Ghazlan and Qurayyah Saudi Arabia in order to determine the impacts of various fuel use scenarios. Natural gas and various types of liquid fuel were considered as fuel inputs in these facilities . . Based on the modeling, recommendations were made about how to best operate the facilities, while still staying in compliance with local air quality standards.

Petrochemical Modeling - Saudi Arabia

Performed CALMET and CALPUFF modeling for a planned expansion at a Saudi Arabian Petrochemical facility. Evaluated the impacts of the plant expansion on ambient SO2, NO2 and PM10 concentrations. Additionally, evaluated fugitive dust impacts during the construction phase.

Knowledge

CREDENTIALS & PROFESSIONAL HONORS

  • M.S., Geosystems, Massachusetts Institute of Technology (MIT), 2000
  • B.A., Physics, University of Pennsylvania, 1997
  • B.A., Geology, University of Pennsylvania, 1997