The effect of ozone on VOC-emission from peatland

Åsmund RinnanQuality &

TechnologyDepartment of

Food ScienceFaculty of Life

SciencesUniversity of Copenhagen

Denmark

People involved

• Riikka Rinnan – sampling, measurements, background

• Toini Holopainen – plant responses to O3

• Jarmo K. Holopainen – plant VOCs• Pertti Pasanen – indoor air VOCs

Rinnan R., Rinnan Å., Holopainen T., Holopainen J.K. & Pasanen P. (2005) Emission of volatile organic compounds (VOC) from boreal peatland microcosms –effects of ozone exposure. Atmospheric Environment 39: 921-930.

Questions to be answered

• Are specific plant species related to emission of certain VOCs?

• What is the general effect of ozone on VOC emissions from peatland?

Peatland microcosms

Peatland microcosms

• Depth 40 cm• ø 11 cm• Water table at -2

cm

• Eriophorum Eriophorum vaginatumvaginatum

• Andromeda polifoliaAndromeda polifolia• Sphagnum mosses• Vaccinium oxycoccus

Ozone exposure

• Computer-controlled growth chambers

• 0, 50, 100 & 150 ppb ozone

• 5 weeks

• VOC collection from 4 microcosms/treatment = 16 in total

• VOC divided into 9 sub-groups

Ozonetreatment

Speciesabundance

0 ppb

50 ppb

100 ppb

150 ppb

Sample 1-4

1 0 0 0

Sample 5-8

0 1 0 0

Sample 9-12

0 0 1 0

Sample 13-16

0 0 0 1

Emissiondata

Plant species vsEmission of VOCs

Ozonetreatment

Speciesabundance

Emissiondata

PLS

B = [ BSpecies abundance BOzone ]

Plant species vsEmission of VOCs

Plant species vsEmission of VOCs

Mean regression coefficientsStandard deviation of regression coefficients

Regression coefficients from Jack-Knifing(Leave-One-Out)

Mean regression coefficients

Standard deviation of regression coefficients

Plant species vsEmission of VOCs

Regression coefficients from Jack-Knifing(Leave-One-Out)

OzonePlant species

Re

gre

ssio

n

coe

ffici

en

t

Vaccinium Andromeda Eriophorum Sphagnum

Plant species vsEmission of VOCs

Re

gre

ssio

n

coe

ffici

en

t

Sphagnum

Andromeda 0 ppb

50 ppb

100 ppb

150 ppb

Shows 2D, in reality 6D

Virtual sample

Effect of ozone onemission of VOCs

100 ppb

Control of virtual sample

InformationNoiseSpecies

abundance

Species abundance = Information + Noise

Effect of ozoneon VOC emission

Information Emissiondata

MLR

Effect of ozoneon VOC emission

Pre

dic

ted

VO

C e

mis

sio

n

Plant PC 1

Real sample

Virtual sample

Predicting VOC-emission

Pre

dic

ted

VO

C e

mis

sio

n

Measured VOC emission

Predictionerror

Real sample

Estimating the uncertaintyof prediction

Speciesabundance

NoiseInformation

Emissiondata

MLR

Pre

dic

ted

VO

C

emis

sio

n

Plant PC

Pre

dic

ted

VO

C

emis

sio

n

Measured VOC emission

Predictionerror

1

4

3

2

The wholeprediction process

Effect of ozoneon emission

Conclusion

• PLS with dummy variables helped us find the specific plants contribution to the VOC-emission

• Creating a virtual sample made it possible to evaluate the effect the ozone-level had on the VOC-emission