Envr 890: Lecture 1 Department of Environmental Science and Engineering UNC, Chapel Hill

Class Objective: Begin Development of a Secondary Organic Aerosol mechanism for Isoprene and learn how to run the ESE Aerosol Smog Chamber in Pittsboro C=C-C=C H H CH 3 H H H

Class Objective: Begin Development of a Secondary Organic Aerosol mechanism for Isoprene and learn how to run the ESE Aerosol Smog Chamber in Pittsboro What are organic aerosols? What fraction of the aerosol environment are they? What do we need to build a chemical mechanism? What do we need to measure? Start collecting papers on Isoprene and SOA formation

Aerosol Associated Organics: An Historical Perspective Aerosol Associated Organics: An Historical Perspective Secondary organic aerosols how much is out there Secondary organic aerosols how much is out there Modeling approaches for SOA Modeling approaches for SOA Analysis Analysis Sampling Sampling Where do we go from here Where do we go from here

What should you get from these lectures? What are SOA Why are they important? How much is there? Are they a constant fraction of TSP or the organic fraction? How are they measured? How are they formed? Which compounds are involved? How do we model them?

What should you get from these lectures? How do we model them? How do we model them? What is equilibrium partitioning What is equilibrium partitioning What is a numerical solution approach What is a numerical solution approach How does this differ from a chemical mechanism approach? How does this differ from a chemical mechanism approach? What are vapor pressure and activity coefficients? What are vapor pressure and activity coefficients? Which compounds contribute to SOA? Which compounds contribute to SOA? What are two major unknowns in current models? What are two major unknowns in current models?

Reasons to study secondary organic aerosol formation (SOA)  Global model calculations are sensitive to fine particles in the atmosphere  Biogenic SOA particles serve as sites for the condensation of other reacted urban organics  The result is haze and visibility reductions  Do SOA push us beyond the AAQS PM2.5 standard? Are SOA more/less toxic than primary particle emissions?

red= +2 o C, yellow =+3 o C, blue = +1 0 C

Thailand

Beijing, in July 1987

Beijing, April 2006

A sunny day in Beijing, April 2006

Air Pollution in Northern Thailand ChiangMai is similar to Los Angeles in the US; it is surrounded by mountains

Mastery of Fire 400,000 years ago in Europe 400,000 years ago in Europe 100,000 years ago in Africa 100,000 years ago in Africa M. N. Cohne, 1977

From a global perspective, fire results in huge emissions of black carbon into the atmosphere Biomass burning6x10 12 g Biomass burning6x10 12 g Fossil fuel burning7x10 12 g Fossil fuel burning7x10 12 g Biogenic aerosols 13-60x10 12 g Biogenic aerosols 13-60x10 12 g

What is the Composition of Particulate Matter???

Composition of LA Particulate Matter (adjusted for smoggy days) ( (Rogge &Cass et al, 1993, Turpin et al, 1991) Percent mass

What are Organic Aerosols? What are Organic Aerosols? organic liquid layer inner solid core inorganic/carbon H2OH2O H 2 SO 4 Semi-volatile organics

What fraction of ambient Particulate matter is organic???

Fresh wood soot (0.5  m scale)

Benzo[a]fluorene Benzo[ghi]perylene Naphthalene Associated with combustion emissions Are PAHs

Professor Grimmer fractionated different exhaust extracts

PAH 2 &3 rings PAHs> 3 rings Total Total -PAHs uv or fluorescence detector HPLC Total hexaneMeCl 2 ACN

painted on the skin of mice painted on the skin of mice implanted in the lungs of rats implanted in the lungs of rats

Total minus the PAH fraction

In the 1980s many studies were showing that combustion particle extracts expressed Ames bacterial mutagenicity Atmospheric reactions and aging could alter the mutagenic responses of combustion particles

Kamens et al, ES&T, 1984,1985

Nitro-PAH were implicated in giving rise to mutagenic increases NO 2

Gas Phase PAH reactions  NPAH ( Arey and Atkinson et al.) Fluoranthene 2-nitrofluoranthene NO 2 + H 2 O + OH H OH + NO 2 H OH NO 2 H

Kinetic models at UNC predicted nitro-PAH in the particle phase from gas phase PAH reactions in sunlight (Fan et al., Atmos. Envir.1995, 1996) NO 2

Do other atmospheric reactions bring about the production of new aerosol matter????

Secondary organic aerosols (SOA) are organic compounds that reside in the aerosol phase as a result of atmospheric reactions that occur in either the gas or particle phases.

Do we see any chemical evidence for SOA formation? Do we see any chemical evidence for SOA formation?

F.W.Went published papers on biogenic emissions from vegetation over 40 years ago. He posed the question, “what happens to the 17.5x10 7 tons of terpene-like hydrocarbons or slightly oxygenated hydrocarbons once they are in the atmosphere each year?”

Went suggests that terpenes are removed from the atmosphere by reaction with ozone attempts to demonstrate “blue haze” formation

Went suggests that terpenes are removed from the atmosphere by reaction with ozone attempts to demonstrate “blue haze” formation by adding crushed pine or fir needles to a jar with dilute ozone.

Over a eucalyptus forest in Portugal Kavouras et al. (1998,1999) show evidence for terpene reaction products in aerosols Over a eucalyptus forest in Portugal Kavouras et al. (1998,1999) show evidence for terpene reaction products in aerosols

Terpenes products Kavouras et al, 1998 ng m -3 pinic acid pinonic acid norpinonic acid Pinonaldehyde Nopinone  -pinene  -pinene

Turpin and co-workers In the LA area (estimated on smoggy days from OC / EC ratios ), as much as % of the aerosol organic carbon comes from secondary aerosol formation (1984 and 1987 samples) In the LA area (estimated on smoggy days from OC / EC ratios ), as much as % of the aerosol organic carbon comes from secondary aerosol formation (1984 and 1987 samples) In Atlanta in 1999, SOA averaged 46% of the total OC but with highs of 88% In Atlanta in 1999, SOA averaged 46% of the total OC but with highs of 88%

Turpin Approach for SOA formation The primary aerosol elemental carbon (EC) pri and particle organic content (OC) pri in an un- reacted airshed are measured and a primary ratio of { OC / EC } pri is determined (Turpin et al for 1984 and 1987 aerosol samples) The primary aerosol elemental carbon (EC) pri and particle organic content (OC) pri in an un- reacted airshed are measured and a primary ratio of { OC / EC } pri is determined (Turpin et al for 1984 and 1987 aerosol samples) Under SOA formation OC tot and EC tot are measured Under SOA formation OC tot and EC tot are measured OC sec = OC tot - OC pri OC sec = OC tot - OC pri OC pri = EC {OC /EC} pri OC pri = EC {OC /EC} pri On smoggy days in California ~ % of the organic carbon comes from secondary aerosol formation On smoggy days in California ~ % of the organic carbon comes from secondary aerosol formation

Spyros Pandis also recently looked at OC/EC ratios (Pittsburgh area) He estimates that SOA formation can account for 35-50% of the organic carbon

OC/EC Ratio and Photochemical Activity OC/EC O3O3 Pittsburgh, 2001

Characteristics of carbonaceous aerosols in Beijing, China Yele Suna, Guoshun Zhuang, Ying Wang, Lihui Han, Jinghua Guo, Mo Dan, Wenjie Zhang, Zifa Wang, Zhengping Hao, Atmos, Environ. 38 (2004) 5991–6004 coal burning, traffic exhaust, and dust from the long-range transport coal burning, traffic exhaust, and dust from the long-range transport Mineral aerosol from outside Beijing accounted for 79% of the total PM10 minerals and 37% of the PM2.5 in winter. Mineral aerosol from outside Beijing accounted for 79% of the total PM10 minerals and 37% of the PM2.5 in winter.

Characteristics of carbonaceous aerosols in Beijing, China Fengkui Duan, Kebin He, Yongliang Ma, Yingtao Jia, Fumo Yang, Yu Lei, S. Tanaka, T. Okuta, Chemosphere 60 (2005) 355–364 OC/EC ratio (on a 1.5 basis showed that SOC accounted more than 50% for the total organic carbon. In winter, the SOC contribution to OC was also significant, and as high as 40%. OC/EC ratio (on a 1.5 basis showed that SOC accounted more than 50% for the total organic carbon. In winter, the SOC contribution to OC was also significant, and as high as 40%.

If we look at the IR spectra of aerosols collected from the smoky mountains, they look like lab aerosols from acid catalyzed particle phase reactions of carbonyls…

Heterogeneous reactions as seen in the IR region (Myoseon Jang) C-O-C bonds

How does the scientific community treat toxic organics that are in the gas and particle phases ?

In the 1980s Yamasaki, Bidelman, Pankow began to investigate the equilibrium distribution of PAHs, alkanes, and chlorinated organics between the gas and the particle phases.

PAH gas + surface   PAH part

Yamasaki (1982) Collects Hi-vol filters+PUF Collects Hi-vol filters+PUF filter PUF

Yamasaki (1982) Collects Hi-vol filters+PUF Collects Hi-vol filters+PUF Analyzes for PAHs Analyzes for PAHs filter PUF

Yamasaki (1982) Collects Hi-vol filters+PUF Collects Hi-vol filters+PUF Analyzes for PAHs Analyzes for PAHs BaA BaA log K y log K y1/Tx1000 filter PUF

Yamasaki (1982) filter PUF Collects Hi-vol filters+PUF Collects Hi-vol filters+PUF Analyzes for PAHs Analyzes for PAHs BaA BaA log K y log K y1/Tx1000

Yamasaki’s relationship This gives a log K y = -a(1/T)+ b which is compound specific This gives a log K y = -a(1/T)+ b which is compound specific Ideally from the regression values of a and b, one can estimate the partitioning of a given compound in any atmosphere at a given temp. and TSP Ideally from the regression values of a and b, one can estimate the partitioning of a given compound in any atmosphere at a given temp. and TSP

log K p = -log P s o + const. Relate solid saturated vapor pressures with K p log P s o log K p naphthaleneBaPPyrene

log K p = -log P o L + const.  PAHs,  alkanes  chlorinated organics slope = -1 log P o (L) log K p

Problems with the theory many aerosols are composed of % organics many aerosols are composed of % organics This gives much more than a mono-layer of coverage This gives much more than a mono-layer of coverage log K p = m log P o (L) + c log K p = m log P o (L) + c

In 1994 James Pankow fixes the theory for liquid particles

Can we chemically / kinetically model SOA Formation??? Numerical fitting Numerical fitting Semi-explicit Semi-explicit

From a modeling perspective Equilibrium Organic Gas-particle partitioning provides a context for addressing SOA formation From a modeling perspective Equilibrium Organic Gas-particle partitioning provides a context for addressing SOA formation

Gas/Particle Partitioning particle Particle type CompoundTemperature Humidity gas Thermodynamic Equilibrium? C gas +surf C part K p will vary with 1/P o

Odum-Seinfeld Model SOA model Y= M o /  HC  HC =  ROG Odum theorytheory

 - pinene- NOx experiments by Odum Y Mo(  g/m 3 ) = M o /  HC Y = M o /  HC

 -pinene

Numerical fitting values for Kom and  for OH, O3, and NO 3 reactions with terpenes and sesquiterpenes were developed by Griffin and Sienfeld et al.  HC ) From the averages for OH, O 3, and NO 3, the amounts of atmospherically reacted terpenes and sesquiterpenes were estimated (  HC ) by Griffin and Sienfeld et al. Y= M o /  HC

Globally, biogenic emissions  13-24x10 12 g y -1 of aerosol mass Gives little insight into the chemical nature of products involve in SOA formation

From a global perspective, fire results in huge emissions of black carbon into the atmosphere Biomass burning6x10 12 g Biomass burning6x10 12 g Fossil fuel burning7x10 12 g Fossil fuel burning7x10 12 g Biogenic aerosols 13-60x10 12 g Biogenic aerosols 13-60x10 12 g

Semi explicit models link gas and particle phases C=O O cis-pinonaldhyde particle C=O O Gas phase reactions

K p = k on /k off [ i gas] + [part] [ i part] k on k off particle k on k off C=O O

K p = k on /k off k off = k b T/h e -Ea /RT

CHO O O CH 3 O O O Criegee2 Criegee1 O O O  -pinene O 3 COOH pinic acid + other products O pinonic acid CHO O COOH + CO, HO 2, OH COOH O norpinonaldehyde norpinonic acid Mechanism

pinonaldehyde

Overall kinetic Mechanism linked gas and particle phase rate expressions linked gas and particle phase rate expressions

Particle Phase reactions particle C=O O cis-pinonaldhyde C=O O polymers Gas phase reactions

Particle Phase reactions particle C=O O cis-pinonaldhyde C=O O polymers Gas phase reactions

Particle Phase reactions C=O O cis-pinonaldhyde C=O O polymers Gas phase reactions

pinonaldehyde 2 x Pinonaldehyde dimerization

ESI-QTOF mass spectrum of SOA from reaction of  -pinene + O 3 + acid seed aerosol (Tolocka et. al., 2004 )

M Na + (ESI-QTOF Tolocka et al, 2003) Particle phase pinonaldehyde dimers from  -pinene +O 3 on acid particles Similar results were obtained by Hartmut Herrmann’s group (Atmos Envir, 2004)

Chemical System  -pinene + NOx+ sunlight + ozone----> aerosols

Simulations of outdoor smog chamber data

0.95 ppm  -pinene ppm NO x O3O3 NO NO 2 model data Time in hours EST ppmV

Gas phase pinonaldehdye O O mg/m 3 Time in hours EST

Particle phase model TSP mg/m 3 Particle phase model TSP mg/m 3 Measured particle mass vs. model data Time in hours EST

Much lower terpene concentrations Different background aerosols which have different chemical and physical properties Low volatility gas phase products will have different interactions with different pre-existing particles The Real Atmosphere

New UNC aerosol smog chamber

Dual 270m 3 chamber fine particle t 1/2 >17 h

0.1 ppmV Toluene ppm NOx

Toluene SOA behavior within an atmospheric HC mixture

SOA from 0.1 ppmV toluene+0.1ppm NOx w/wo 3ppmC HC mixture Without HC mix

SOA from terpene mixtures 0.05 ppmV  -pinene 0.02 ppmV d-limonene 0.05 ppm NO X

SOA from terpene mixtures

How do we represent changing particle size distributions??

Need to integrate particle sizes into our mechanisms

nm minutes mass 7.5 nm particles 15 nm particles

Model Simulations of UNC Toluene/NOx Experiments O3O3  -pinene

10 ppbV  -pinene +40 ppb O 3

new particles/cc = 3x10 7 x  -pinene reacted 1.77

# stable nuclei = Ax10 [reacted organic] x [H 2 SO 4 ] n Gas phase Sulfuric Acid and nucleation

# stable nuclei = Ax10 [reacted organic] x [H 2 SO 4 ] n Final point: How important is Isoprene in the formation of SOA? C=C-C=C H H CH 3 H H H

Primary and Secondary Contributions to Ambient PM in the Midwestern United States Lewandowki, and Schauer, et al., ES&T 2008

Sesquiterpenes (C 15 H 24 )

On a reacted mass basis, b- caryophyllene and a-humulene have much higher aerosol potentials than monoterpenes (Griffin et al., 1999).  Yield  -carophyllene %  -humulene d-limonene  -pinene  -pinene

# stable nuclei = Ax10 [reacted organic] x [H 2 SO 4 ] n We do not have an Isoprene in the formation of SOA?

Unique SOA poly-ols from isoprene reaction with OH (Magda Claeys et al. Science, 2004)