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Review of Biogenic Volatile Organic Compounds and Their Products. Brian Lamb (1) , Daniel Grosjean (2) , Betty K. Pun (3) , and Christian Seigneur (3) Biogenic Day 9-10 December 1999. (1) Washington State University, Pullman, WA (2) DGA, Inc., Ventura, CA (3) AER, San Ramon, CA.

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Review of Biogenic Volatile Organic Compounds and Their Products


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review of biogenic volatile organic compounds and their products

Review of Biogenic Volatile Organic Compounds and Their Products

Brian Lamb(1), Daniel Grosjean(2),

Betty K. Pun(3), and Christian Seigneur(3)

Biogenic Day

9-10 December 1999

(1) Washington State University, Pullman, WA

(2) DGA, Inc., Ventura, CA

(3) AER, San Ramon, CA

introduction

Condensable

products

Emissions

Atmospheric

reactions

Gas/particle

partition

PM

O3

Introduction

Biogenic compounds are precursors to ozone (O3) and particulate matter (PM)

biogenic volatile organic compounds
Biogenic Volatile Organic Compounds

Emission %

in North America

  • Isoprene 31%
  • Methylbutenol (MBO) 5%
  • Monoterpenes + sesquiterpenes 22%
  • Reactive oxygenates 16%
  • Less reactive oxygenates 26%
isoprene
Isoprene
  • Sampling, analytical, eddy covariance flux methods are well-developed

Emission Characteristics

  • Dominant VOC
  • From deciduous species and spruce
  • During day-light hours only
  • Depends on leaf temperature and PAR
isoprene data needs
Isoprene Data Needs
  • Vegetation types other than oaks, poplars, aspen, and spruce
  • Effects of temperature history and season
  • Landcover data
monoterpenes
Monoterpenes
  • Predominant compounds: a-, b-pinene, limonene, and D3-carene

Emission Characteristics

  • From conifers and some deciduous species
  • Depends on temperature
    • Some Mediterranean oaks emit terpenes with isoprene-like light, temperature dependence
monoterpene data needs
Monoterpene Data Needs
  • Emission capacities of individual monoterpene compounds
  • Characterization of emission response to
    • rainfall / humidity
    • herbivory
  • Canopy-scale measurements
  • Comparison of measurements and inventory models
sesquiterpenes
Sesquiterpenes
  • Semivolatile, low emission capacities
  • May contribute up to 16% of total BVOC landscape-scale flux

Data Needs

  • Identification of individual sesquiterpenes and their emission capacities
  • Canopy-scale measurements
  • Regional emissions estimates
oxygenated voc
Oxygenated VOC
  • Methylbutenol, emitted via the light-dependent chloroplast mechanism
  • Other oxygenates emitted by defense mechanisms or cut and drying vegetation
  • Regional emissions difficult to quantify due to intermittent emissions
  • No canopy-scale information
  • No evaluation at landscape scale
biogenic emissions modeling
Biogenic Emissions Modeling

e = area-average emission capacity

D = foliar density

g = activity factor for light, temperature, leaf age

d = activity factor for other factors

r = canopy escape efficiency

canopy modeling
Canopy Modeling
  • Microclimate within a forest canopy as a function of height
    • temperature (heat flux)
    • PAR
measurements and modeling isoprene
Measurements and Modeling (Isoprene)
  • Measurement scale-up studies
    • 40% difference between leaf and canopy scales
  • Reconciliation of measurements with models
    • 30% difference between flux measurement and model for site specific applications
    • factor of 1.2 to 2 using inverse modeling of ambient concentrations
chemical functionality
Chemical Functionality
  • Saturated aliphatics
    • Alkanes, alcohols, aldehydes, ketones, acids, esters, ethers
  • Aromatics
  • Unsaturated Aliphatics
    • Alkenes, dienes, terpenes (1 to 3 C=C), sesquiterpenes (1 to 3 C=C)
  • Unsaturated Oxygenates
    • alcohols, esters, aldehydes, ketones
kinetics of saturated aliphatics and aromatics
Kinetics of Saturated Aliphatics and Aromatics
  • Saturated aliphatics react only with OH
  • Aromatics react mainly with OH, NO3 may be a minor pathway
  • Missing kinetic data for hexanal, camphor, cineole, and p-cymene can be estimated by structure-reactivity relationships
  • Acetone has the maximum t1/2(1) = 36 days
  • Hexanal has the minimum t1/2(1) = 6 hours

(1) OH = 106 molec/cm3

kinetics of unsaturated compounds
Kinetics of Unsaturated Compounds

Unsaturated VOC react with OH, O3, and NO3

t1/2,OH(1) (hours) t1/2, O3(2) (hours)

alkenes 3.0 - 23 1.3 - 160

isoprene 1.9 20

terpenes 0.53 - 3.6 0.01 - 280

sesquiterpenes 0.65 - 4.1 0.02 - >500

oxygenates 1.2 - 6.6 0.60 - 130

(1) OH = 106 molec/cm3; (2) O3 = 30 ppb

highly reactive compounds
Highly Reactive Compounds

a-terpinene a-humulene Linalool

Reaction with O3 may be the dominant removal process for the more reactive BVOC

first generation products
First-Generation Products
  • Example: OH + a-pinene
    • Pinonaldehyde, acetone, formaldehyde
    • Organic nitrates, hydroxy nitrates, dihydroxy nitrates, dihydroxycarbonyls
  • For O3 and OH reactions
    • Detailed information for alkenes, a-, and b-pinene, and unsaturated alcohols
    • Limited or no information for >20 BVOC
  • Less information on NO3 reaction
soa formation
SOA Formation
  • 14 BVOC known to form SOA
    • 10 terpenes (a-pinene most studied)
    • 2 sesquiterpenes
    • 2 unsaturated alcohols
  • Isoprene does not form SOA
  • SOA composition studied for 5 BVOC (reactions with O3 and OH only): a-, b-pinene, d-limonene, terpinolene, D3-carene
reactions of first generation products
Reactions of First-Generation Products
  • Kinetic data for first-generation products are limited
    • Aldehydes removed rapidly by OH reaction
    • Unsaturated carbonyls react with O3
  • Product studies conducted for only 6 first-generation compounds
    • Very limited information on second-generation products
detailed bvoc mechanisms
Detailed BVOC Mechanisms
  • With the exception of isoprene and a-pinene, detailed mechanisms cannot be constructed for BVOC
o 3 formation from bvoc

CH3CH2

CH2CH2OH

+ OH

C = C

H

H

·

CH3CH2CH

CHCH2CH2OH

OH

HO2

NONO2

CH3CH2CH(OH)CCH2CH2OH

O

+ HO2

O3

O

·

CH3CH2CHOH + HCCH2CH2OH

O2

HO2

O

CH3CH2CHO

HO2

+ HOCH2CH2CH(OH)CCH2CH2OH

O3 Formation from BVOC

·

CH3CH2CHCHCH2CH2OH

OH

NO2

NO2

O2, NO

O2, NO

CH3CH2CHCH(OH)CH2CH2OH

CH3CH2CH(OH)CHCH2CH2OH

O

O

·

·

Isom.

+ O2

u.d.

·

CH2CH2CH(OH)CH(OH)CH2CH2OH

NO2

O2, NO

·

OCH2CH2CH(OH)CH(OH)CH2CH2OH

Isom.

·

HOCH2CH2CH(OH)C(OH)CH2CH2OH

O2

organic aerosol partition theories
Organic Aerosol Partition Theories
  • Saturation
    • Fixed yield approach
  • Absorption into an organic phase
  • Aqueous dissolution

Total

concentration

(Ctot)

Cgas = Psat

Cparticle = Ctot - Psat

Psat

Gas phase only

Cgas = Ctot

K

Cparticle

Cgas

H

Cparticle

Cgas

modules under development

OC (g)

OC (aq)

OC (g)

OC (l)

Modules Under Development
  • Externally Mixed Aerosols
  • Surrogate Species

Type A (Aqueous) Type B (Organic)

e.g., Malic acid, e.g., Octadecanoic acid

Glyoxalic acid

data needs
Data Needs

Chemistry

  • Products studies
  • Mechanisms
  • SOA composition

SOA Partition

Emissions

  • Identity of SOA species
  • Theoretical development
  • Individual terpene species
  • Sesquiterpenes and oxygenates
  • Need instrument development work
acknowledgement
Acknowledgement

This work is funded by the Coordinating Research Council (CRC), Contract Number A-23