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Donald Dabdub University of California, Irvine MAE-164

Basics of Air Pollution Modeling – an Outline. Donald Dabdub University of California, Irvine MAE-164. A bit about my background. Background Born in Masaya, Nicaragua. Fluent in Spanish. B.S. Chemical Engineering – Lehigh University.

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Donald Dabdub University of California, Irvine MAE-164

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  1. Basics of Air Pollution Modeling – an Outline Donald Dabdub University of California, Irvine MAE-164

  2. A bit about my background Background • Born in Masaya, Nicaragua. • Fluent in Spanish. • B.S. Chemical Engineering – Lehigh University. • Graduate Education in Chemical Engineering - Caltech. http://albeniz.eng.uci.edu/dabdub/

  3. A bit about my research interests Atmospheric Sciences • Mathematical modeling of urban and global air pollution. • Dynamics of atmospheric aerosols. Secondary organic aerosols. • Impact of energy generation on air quality. • Chemical reactions at gas-liquid interfaces. Computational Science • Massively parallel computations. • Numerical analysis of partial differential equations. • Sensitivity analysis. http://albeniz.eng.uci.edu/dabdub/

  4. What I teach: Introduction to Engineering Computations • Main goal:to develop computational programming skills and learn computational tools to be used in the solution of engineering problems. • Prerequisites: Strong desire to work with computers. No previous programming experience required. No knowledge of calculus required. • Focus: FORTRAN • Difficulty: MAE-10 is a fast-paced engineering college entry level course. http://albeniz.eng.uci.edu/mae10

  5. Air is a fundamental body “These four bodies are fire, air, water, earth. Fire occupies the highest place among them all, earth the lowest, and two elements correspond to these in their relation to one another, air being nearest to fire, water to earth.” Aristotle Meteorology, 350 B.C.

  6. An aggregate of effluviums “I have often suspected that air is not, as many imagine, a simple and elementary body, but a confused aggregate of effluviums” Robert Boyle (1627-1691)

  7. Is air N15O4? If air were not a compound, the heavier gas oxygen should sink below nitrogen. Thus, oxygen should be found at higher concentrations at the very bottom of the atmosphere. Humphrey Davy (1778-1829)

  8. What else is in air? • After painstaking analyses, no matter how hard he tried to remove all the oxygen and nitrogen in the air, a small inert fraction was always left over. Composition of dry unpolluted air by volume Nitrogen 78.084% Oxygen 20.946% Argon 0.934% CO2 ~360 ppm Henry Cavendish (1731-1810)

  9. Applications of AQMs • Establishment of emission control legislation. • Evaluation of control strategies. • Planning of locations of future sources of air contaminants. • Planning for the control of air pollution episodes. • Assessment of responsibility for existing levels of air pollution.

  10. Southern California Air Quality

  11. Southern California Air Quality

  12. Tell me when your eyes and lungs start to burn. Gee, it smells likebleach!

  13. WHAT’S THE FUSS? • SUSTENANCE: AIR, WATER, FOOD • CAN GO THE LEAST LENGTH OF TIME WITHOUT AIR • ATMOSPHERIC CONCENTRATIONS INCREASING (ppb) SPECIES CLEAN POLLUTED LOS ANGELES* SO2 1-10 20-200 140 CO 120 1,000-10,000 8,000 NO 0.01-0.05 50-750 NO2 0.1-0.5 50-250 170 O3 20-80 100-500 150 HNO3 0.02-0.3 3-50 NH3 1 10-25 NMHCs 500-1,200 Seinfeld, Atmospheric Chemistry and Physics of Air Pollution (1986) *1998 LA Data from SCAQMD, max concen. in 1 hr

  14. AIR POLLUTION EPISODES LOCATION DATE POLLUTANTS EFFECTS Meuse Valley, Dec. 1–5, 1930 SO2 63 deaths, chest pain, cough,Belgium (10 – 40 ppm) eye and nasal irritation, all ages Donora, PA Oct. 26–31, 1948 SO2 + particles 20 deaths, chest pain, cough eye and nasal irritation, mostly older people affected London Dec. 5–9, 1952 SO2 + particles 4000 deaths New York Nov. 24–30, 1966 SO2 + particles 168 deaths Seinfeld, Atmospheric Chemistry and Physics of Air Pollution (1986)

  15. POLLUTANT MAJOR SOURCES OZONE (O3) Formed in the atmosphere from VOCs NO2, and sunlight. CO, NOx Any combustion source. VOCs Combustion, solvents, petroleum processing and storage, pesticides, and natural sources. PM10 Road dust, agriculture and construction, and incomplete combustion. WHERE ARE THEY FROM?

  16. POLLUTANT AVG. TIME CALIF. FEDERAL Ozone (O3) 1 hour 0.09 ppm 0.12 ppm 8 hour – 0.08 ppm Carbon 8 hour 9 ppm 9 ppm Monoxide (CO) 1 hour 20 ppm 35 ppm Nitrogen Ann. Arith. Mean – 0.053 pm Dioxide (NO2) 8 hour 0.25 ppm – Respirable Ann. Geom. Mean 30 g/m3 – Particulate (PM10) Ann. Arith. Mean – 50 g/m3 24 hour 50 g/m3 150 g/m3 Fine 24 hour – 65 g/m3 Particulate (PM2.5) Ann. Arith. Mean – 15 g/m3 CALIFORNIA AND FEDERAL STANDARDS Limits for SO2 and Lead exist but are not shown

  17. Motivation Visibility Impact on Climate Human Health

  18. The Big Picture

  19. condensation nucleation evaporation surface chemistry coagulation Aerosol Processes aqueous chemistry diffusion water uptake activation resuspension subcloud scavenging oxidation precursor emissions primary emissions dry deposition

  20. emissions (VOC, NOx, SO2, NH3) meteorological fields cloud/fog microphysics wet deposition Comprehensive Air Quality Model Meteorologicalfields vertical diffusion & dry deposition gas-phase chemistry GAS-PHASE MODULE gas-phase I.C.s & B.C.s time dependent gas-phase concentrations vertical profiles particle emissions R.H. aerosol I.C.s & B.C.s inorganic species gas-aerosol equilibrium secondary organic aerosol gas to particle conversion gas to particle conversion AEROSOL MODULE aerosol size composition distribution gas-phase concentrations aqueous- phase chemistry AQUEOUS-PHASE MODULE

  21. Gas-Phase Photohemistry Condensible Organic Vapors Primary Organic Particulate Emissions (OC, EC) SO2 Emissions Primary Gaseous Organics Sea Salt Gas-Phase Photohemistry Primary Inorganic Particulate Emissions (dust, fly ash, etc.) H2SO4 HNO3 Primary H2SO4 Emissions H2O Gas-Phase Photohemistry NH3 Emissions NOx Emissions Atmospheric Aerosol

  22. Combustion Process Emissions primary OC - EC H2O SO2 Emissions Gas-Phase Photochemistry Primary H2SO4 H2SO4 S(IV) HCl emissions H+, SO42-, HSO4-,H2SO4 HCl Cl-, Na+ NH3 NH4+,OH- primary OC - EC NH3 Emissions Sea-Salt Emission Dust, fly ash metals Secondary OC Condensible Organics Gas-Phase Photochemistry NO3-,H+ Ca2+,Mg2+, Fe3+, etc. HNO3 Gas-Phase Photochemistry NOx Emissions Dust, Fly Ash Emissions Gaseous Organics Emissions

  23. Processes • Emissions: primary particles, condensible species, gas-phase precursors • Deposition: removal at the surface • Condensation: gas-to-particle conversion, conserved particle number • Evaporation: particle-to-gas conversion, conserved particle number • Advection: primarily horizontal motion with wind field • Settling: primarily vertical motion of particles due to gravity • Turbulent Diffusion: primarily vertical motion • Coagulation: collision of two particles to form one, conserves aerosol mass • Nucleation: formation of new particles from gas-phase compounds

  24. Local Pollution Effects LA basin fires. October 29, 2003

  25. Different types of models • Numerical Weather Predictions • Regional Airshed modeling • Chemical Transport Models • Global Circulation Models

  26. Numerical Weather Predictions

  27. CTM-Aerosol Model 53 Gas Species 72 Aerosols: 9 species, 8 sizes 277 Gas phase Reactions 22.5 km 25 vertical -layers 35 Cells 0.04 km 72 Cells Each Cell: 5° x 5 °

  28. Sulfate Surface • Northern hemisphere shows highest surface values • Industrialized regions in Southern Hemisphere

  29. Mass Mean Diameter • Smallest particles in fine mode lie over continental regions • Largest particles in coarse mode lie over dust sources Fine Mode Coarse Mode

  30. General Dynamic Equation Processes to Model • Advection-Diffusion • Thermodynamics • Dynamics (mass transport) • Primary Emissions • Dry Deposition • Nucleation of new particles • Aerosol-Phase Chemistry

  31. South Coast Air Basin of California http://www.visibleearth.nasa.gov/

  32. 10.6 kg Ozone 3.97 kg Ozone PhotochemicalReactivity high reactivity 1 kg m-xylene low reactivity 1 kg toluene

  33. Air Pollution Modeling on Parallel Supercomputers 47 Gas Species 152 Aerosols: 19 species, 8 sizes 125 Reactions 1100 m 671 m 308 m 154 m 38 m 0 m 30 Cells 80 Cells Each Cell: 5 x 5 km2

  34. Available Measurements for Model Input and Evaluation • Meteorology • Surface wind, RH, temperature (64 sites, every hour) • Vertical profiles of wind, RH, temperature (12 sites, every 4 hours) • Gas-Phase Concentrations • O3, NO, NO2, CO (every hour) • VOCs, speciated HCs, HNO3, NH3 (8 sites, every 4 hours) • Aerosol-Phase Concentrations • Sulfate, Nitrate, Sodium, Chloride, Ammonium, Trace Species, OC, EC, PM10 (8 sites, every 4 hours) • Size/Composition distributions (2 sites, every 4 hours) • Other • Upper air concentration measurements (3 airplanes, every 6 hours) • Aqueous-phase concentration measurements (1 site)

  35. Hardware Intel 440LX chipset 300 MHz Pentium II processor 128 MByte 10-ns SDRAM memory 3.1 GByte Quantum EIDU-DMA disk 100 Mbit/s ethernet adapter

  36. Software The machines run Red Hat Linux EASY and DQS for job scheduling MPI-ch, lam-MPI and PVM formessage passing Compilers for Gnu C, C++ and Fortran (g77) Absoft's f77 and f90 compilers Highly optimized BLAS and FFT’s for the Intel Pentium II.

  37. NetworkTwo 100 Mb/s full duplex 36-port Fast Ethernet switches with6.6 Gbit/s backplane and trunked Gigabit Ethernet fiber interconnectmodules are used for communications between nodes

  38. High Performance Computing Resources Dabdub group clusters are incorporated into UCI’s “medium performance cluster” (MPC) maintained by Network & Academic Computing Services Part of MPC in Engineering Gateway at UCI • The Dabdub group currently has ~200 processors in the MPC • Recent computer upgrades includes ~100 additional processors • Additional resources are available in Barcelona: Mare Nostrum

  39. Recent Applications • New discoveries in atmospheric chlorine production. • Dynamics of Secondary Organic Aerosol. • The impact of distributed energy generation. • Dynamics of renoxification processes.

  40. Models and Insight • PROBLEM: What is the impact of new chlorine chemistry findings in the air quality of the South Coast Air Basin of California? • Host Model : CIT Airshed Model during 1993 for the South Coast Air Basin of California.

  41. DO3Contours: Friday, September 9, 1993 all units in ppb

  42. Lake Clarity Visibility in Meters

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