the effect of ozone on voc- emission from peatland Åsmund rinnan quality & technology...
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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