Donald DabdubDonald DabdubUniversity of California, IrvineUniversity of California, Irvine

MAE-164MAE-164

Basics of Air Pollution Modeling – an Outline

Basics of Air Pollution Modeling – an Outline

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/

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/

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

Air is a fundamental bodyAir 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.”

AristotleMeteorology, 350 B.C.

AristotleMeteorology, 350 B.C.

An aggregate of An aggregate of effluviumseffluviums

““I have often suspected I have often suspected that air is not, as many that air is not, as many imagine, a simple and imagine, a simple and elementary body, but a elementary body, but a confused aggregate of confused aggregate of effluviums”effluviums”

Robert Boyle (1627-1691)Robert Boyle (1627-1691)

Is air NIs air N1515OO44??

If air were not a compound, the If air were not a compound, the heavier gas oxygen should sink heavier gas oxygen should sink below nitrogen. Thus, oxygen below nitrogen. Thus, oxygen should be found at higher should be found at higher concentrations at the very bottom concentrations at the very bottom of the atmosphere.of the atmosphere.

Humphrey Davy (1778-1829)Humphrey Davy (1778-1829)

What else is in air?What else is in air?

• After painstaking analyses, no matter After painstaking analyses, no matter how hard he tried to remove all the how hard he tried to remove all the oxygen and nitrogen in the air, a small oxygen and nitrogen in the air, a small inert fraction was always left over.inert fraction was always left over.

Henry Cavendish (1731-1810)

Henry Cavendish (1731-1810)

Composition of dry unpolluted air by volume

Nitrogen 78.084%Oxygen 20.946%Argon 0.934%CO2 ~360 ppm

Nitrogen 78.084%Oxygen 20.946%Argon 0.934%CO2 ~360 ppm

Applications of AQMsApplications of AQMs

• Establishment of emission control legislation.Establishment of emission control legislation.

• Evaluation of control strategies.Evaluation of control strategies.

• Planning of locations of future sources of air Planning of locations of future sources of air contaminants.contaminants.

• Planning for the control of air pollution episodes. Planning for the control of air pollution episodes.

• Assessment of responsibility for existing levels of Assessment of responsibility for existing levels of air pollution.air pollution.

Southern California Air Southern California Air QualityQuality

Southern California Air Southern California Air QualityQuality

Tell me when youreyes and lungs start

to burn.

Gee, it smells likebleach!

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 500-1,200Seinfeld, Atmospheric Chemistry and Physics of Air Pollution (1986)*1998 LA Data from SCAQMD, max concen. in 1 hr

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, cougheye and nasal irritation, mostly

older people affected

LondonDec. 5–9, 1952SO2 + particles 4000 deaths

New YorkNov. 24–30, 1966SO2 + particles 168 deaths

Seinfeld, Atmospheric Chemistry and Physics of Air Pollution (1986)

WHERE ARE THEY FROM?

POLLUTANT MAJOR SOURCES

OZONE (O3) Formed in the atmosphere from VOCsNO2, and sunlight.

CO, NOx Any combustion source.

VOCs Combustion, solvents, petroleumprocessing and storage, pesticides, and natural sources.

PM10 Road dust, agriculture and construction,and incomplete combustion.

CALIFORNIA AND FEDERAL STANDARDS

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

Limits for SO2 and Lead exist but are not shown

MotivationMotivation

Visibility

HumanHealth

Impact onClimate

The Big PictureThe Big Picture

Aerosol ProcessesAerosol Processes

coagulationresuspension

nucleation

subcloudscavenging

wateruptake

primary emissions

aqueouschemistry

surfacechemistry

drydeposition

activation

diffusion

precursor emissions

condensationevaporation

oxidation

GAS-PHASE MODULE

AEROSOL MODULE

AQUEOUS-PHASE MODULE

particle emissions

R.H.

aerosolI.C.s & B.C.s

emissions(VOC, NOx,

SO2, NH3)

gas-phaseI.C.s & B.C.s

gas to particle conversion

vertical diffusion &dry deposition

gas-phase chemistry

gas to particle conversion

inorganic speciesgas-aerosol equilibrium

secondary organicaerosol

aqueous-phase

chemistry

cloud/fogmicrophysics

wet deposition

meteorologicalfields

aerosol size composition distributiongas-phase concentrations

time dependent gas-phase concentrations

vertical profiles

Comprehensive Air Quality Comprehensive Air Quality ModelModel

Meteorologicalfields

Meteorologicalfields

Atmospheric AerosolAtmospheric Aerosol

Primary Organic ParticulateEmissions (OC, EC)

SO2 Emissions

Gas-Phase Photohemistry

Primary H2SO4

Emissions

NH3 Emissions

NOx Emissions

Gas-Phase Photohemistry

Gas-Phase Photohemistry

Primary InorganicParticulate Emissions

(dust, fly ash, etc.)

Primary GaseousOrganics

Condensible OrganicVapors

H2SO4

H2O

HNO3

Sea Salt

SO2 Emissions

PrimaryH2SO4

Gas-PhasePhotochemistry

NH3

Emissions

NH3

NOx Emissions

Gas-PhasePhotochemistry

Combustion Process Emissionsprimary OC - EC

H2SO4

H+, SO42-,

HSO4-,H2SO4

NH4+,OH-

HNO3

NO3-,H+

primary OC - EC

Gaseous Organics Emissions

Gas-PhasePhotochemistry

CondensibleOrganics

Secondary OC

Dust, Fly Ash Emissions

Dust, fly ashmetals

Sea-SaltEmission

HClemissions

Cl-,

Na+

HCl

H2O

Ca2+,Mg2+,Fe3+, etc.

S(IV)

ProcessesProcesses

• Emissions: Emissions: primary particles, condensible species, gas-phase primary particles, condensible species, gas-phase precursorsprecursors

• Deposition: Deposition: removal at the surfaceremoval at the surface

• Condensation: Condensation: gas-to-particle conversion, conserved particle gas-to-particle conversion, conserved particle numbernumber

• Evaporation: Evaporation: particle-to-gas conversion, conserved particle numberparticle-to-gas conversion, conserved particle number

• Advection: Advection: primarily horizontal motion with wind fieldprimarily horizontal motion with wind field

• Settling: Settling: primarily vertical motion of particles due to gravityprimarily vertical motion of particles due to gravity

• Turbulent Diffusion: Turbulent Diffusion: primarily vertical motionprimarily vertical motion

• Coagulation: Coagulation: collision of two particles to form one, conserves collision of two particles to form one, conserves aerosol massaerosol mass

• Nucleation: Nucleation: formation of new particles from gas-phase compoundsformation of new particles from gas-phase compounds

Local Pollution EffectsLocal Pollution Effects

LA basin fires. October 29, 2003LA basin fires. October 29, 2003

Different types of modelsDifferent types of models

• Numerical Weather PredictionsNumerical Weather Predictions

• Regional Airshed modelingRegional Airshed modeling

• Chemical Transport ModelsChemical Transport Models

• Global Circulation ModelsGlobal Circulation Models

Numerical Weather Numerical Weather PredictionsPredictions

CTM-Aerosol Model

22.5 km53 Gas Species72 Aerosols: 9 species, 8 sizes277 Gas phase Reactions

53 Gas Species72 Aerosols: 9 species, 8 sizes277 Gas phase Reactions

35Cells

72 CellsEach Cell: 5° x 5 °

0.04 km

25 vertical-layers

Sulfate

Northern hemisphere shows highest surface values

Industrialized regions in Southern Hemisphere

Surface

Mass Mean Diameter

Fine Mode Coarse Mode

Smallest particles in fine mode lie over continental regions

Largest particles in coarse mode lie over dust sources

General Dynamic EquationGeneral Dynamic Equation

Processes to ModelProcesses to Model• Advection-DiffusionAdvection-Diffusion

• ThermodynamicsThermodynamics

• Dynamics (mass transport)Dynamics (mass transport)

• Primary EmissionsPrimary Emissions

• Dry DepositionDry Deposition

• Nucleation of new particlesNucleation of new particles

• Aerosol-Phase ChemistryAerosol-Phase Chemistry

Q

tuQ K Q

Q

t

Q

t

Q

t

Q

tmk

mk

mk m

k

condevap

mk

sources

mk

nucl

mk

chemistry

/ /sinks

South Coast Air Basin of CaliforniaSouth Coast Air Basin of California

http://www.visibleearth.nasa.gov/http://www.visibleearth.nasa.gov/

high reactivity

low reactivity

PhotochemicalReactivity

10.6 kgOzone

3.97 kgOzone

1 kgm-xylene

1 kg toluene

H 3C

H 3C

H3C

Air Pollution Modeling on Parallel Air Pollution Modeling on Parallel SupercomputersSupercomputers

1100 m

38 m

154 m

0 m

308 m

671 m

80 Cells

30Cells

47 Gas Species152 Aerosols: 19 species, 8 sizes125 Reactions

47 Gas Species152 Aerosols: 19 species, 8 sizes125 Reactions

Each Cell: 5 x 5 km2

Available Measurements Available Measurements for Model Input and for Model Input and

EvaluationEvaluation• MeteorologyMeteorology

– Surface wind, RH, temperature (64 sites, every hour)Surface wind, RH, temperature (64 sites, every hour)

– Vertical profiles of wind, RH, temperature (12 sites, every 4 hours)Vertical profiles of wind, RH, temperature (12 sites, every 4 hours)

• Gas-Phase ConcentrationsGas-Phase Concentrations– OO33, NO, NO, NO, NO22, CO (every hour), CO (every hour)

– VOCs, speciated HCs, HNOVOCs, speciated HCs, HNO33, NH, NH33 (8 sites, every 4 hours) (8 sites, every 4 hours)

• Aerosol-Phase ConcentrationsAerosol-Phase Concentrations– Sulfate, Nitrate, Sodium, Chloride, Ammonium, Trace Species, OC, EC, Sulfate, Nitrate, Sodium, Chloride, Ammonium, Trace Species, OC, EC,

PMPM1010 (8 sites, every 4 hours) (8 sites, every 4 hours)

– Size/Composition distributions (2 sites, every 4 hours)Size/Composition distributions (2 sites, every 4 hours)

• OtherOther– Upper air concentration measurements (3 airplanes, every 6 hours)Upper air concentration measurements (3 airplanes, every 6 hours)

– Aqueous-phase concentration measurements (1 site)Aqueous-phase concentration measurements (1 site)

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

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

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.

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.

NetworkTwo 100 Mb/s full duplex 36-port Fast Ethernet switches with

6.6 Gbit/s backplane and trunked Gigabit Ethernet fiber interconnectmodules are used for communications between nodes

NetworkTwo 100 Mb/s full duplex 36-port Fast Ethernet switches with

6.6 Gbit/s backplane and trunked Gigabit Ethernet fiber interconnectmodules are used for communications between nodes

High Performance Computing High Performance Computing ResourcesResources

Part of MPC in Engineering Gateway at UCI

Dabdub group clusters are incorporated into UCI’s “medium performance cluster” (MPC) maintained by Network & Academic Computing Services

• 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

Recent ApplicationsRecent Applications

• New discoveries in atmospheric chlorine New discoveries in atmospheric chlorine production.production.

• Dynamics of Secondary Organic Aerosol.Dynamics of Secondary Organic Aerosol.

• The impact of distributed energy generation.The impact of distributed energy generation.

• Dynamics of renoxification processes.Dynamics of renoxification processes.

Models and InsightModels and Insight

• PROBLEM: What is the impact of new chlorine PROBLEM: What is the impact of new chlorine chemistry findings in the air quality of the South chemistry findings in the air quality of the South Coast Air Basin of California?Coast Air Basin of California?

• Host Model : CIT Airshed Model during 1993 for Host Model : CIT Airshed Model during 1993 for the South Coast Air Basin of California.the South Coast Air Basin of California.

Contours: Friday, September 9, 1993

all units in ppb

-10 -5 0 5 10

Riverside N. Long Beach

Los Angeles

[O3]: 1000: Cl Chem - Base

-10 -5 0 5 10

Riverside N. Long Beach

Los Angeles

[O3]: 1200: Cl Chem - Base

-10 -5 0 5 10

Riverside N. Long Beach

Los Angeles

[O3]: 1500: Cl Chem - Base

-10 -5 0 5 10

Riverside N. Long Beach

Los Angeles

[O3]: 1800: Cl Chem - Base

Lake Clarity

18

20

22

24

26

28

30

32

1965 1970 1975 1980 1985 1990 1995 2000

Visibility in Meters

Growth TrendsGrowth Trends

0%

100%

200%

300%

1980 1990 2000 2010 2020

Nor

mal

ized

to

1980

Population

Vehicle Miles

Traveled

Gross State

Product

Emission TrendsEmission Trends

0%

50%

100%

150%

1980 1990 2000 2010 2020

Nor

mal

ized

to

1980 CO2

NOx

SOx

ROG

CO

PM10PM10 TrendsTrends

0

100

200

300

Max

24-

hr P

M10

(µg

/m3)

South CoastSouth Coast

State StandardState Standard

San Joaquin ValleySan Joaquin Valley

0.0

0.1

0.2

0.3

0.4

0.5

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

Max 1

-hr

Ozon

e (

pp

m)

State StandardState Standard

South South CoastCoast

San Joaquin ValleySan Joaquin Valley

Ozone TrendsOzone Trends

Historical Ozone Levels

0

50

100

150

200

250

300

1965 1970 1975 1980 1985 1990 1995 2000

Year

Above CaliforniaOzone Standard

Stage I Episodes

Stage II Episodes

Num

ber

of D

ays

Stage II > 350 ppb O3

Stage I > 200 ppb O3

SOUTH COAST O3 HISTORY

0.0

0.1

0.2

0.3

0.4

0.5

0.6

1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

Years

Max

O3

(ppm

)

1952

– P

rof.

Haa

gen-

Sm

it di

scov

ers

smog

form

atio

n

1963

– C

lean

Air

Act

(C

AA

)

1970

– E

PA

cre

ated

, CA

A A

mm

end.

1976

– V

olvo

intr

oduc

es fi

rst c

ar to

us

e 3-

way

cat

alys

t

1984

– S

mog

Che

ck P

rogr

am

1990

– C

AA

A

1994

– S

mog

Che

ck II

197

1 –

CA

RB

ado

pts

1st

aut

o N

Ox

sta

ndar

dsE

PA

pro

mu

lgat

es N

AA

QS

NAAQS

Improvement Over Past 20 Improvement Over Past 20 YearsYears

-80%

-60%

-40%

-20%

0%NitrogenDioxide

SulfurDioxide

CarbonMonoxide

Ozone PM10 Air Toxics(Cancer

Risk)

Perc

en

t C

han

ge

ApproachinApproachin

g g StandardsStandards

Attained Attained StandardsStandards

T H A N K S ! !T H A N K S ! !