Ozone Production in Biomass Burning Plumes Douglas Finch Paul Palmer
Ozone Production in Biomass Burning Plumes Douglas Finch Paul Palmer
Introduction Plume Tracking Chemical Pathways Summary
Air Quality - A global problem
• Biomass burning can cause high air pollution events downwind
• What happens as this plume
travels? • What happens when the
plume interacts with other pollutants?
Introduction Plume Tracking Chemical Pathways Summary
Ozone from Wildfires
O3
• NOx and VOCs in different concentration lead to different reactions
• Some plumes have net
production of ozone - some have net loss
• What conditions do these
different scenarios occur in?
O3
O3 O3
O3
VOCs
NOx
• Can we capture the plumes chemistry in the model observed during BORTAS? (See Palmer et al, 2013)
Introduction Plume Tracking Chemical Pathways Summary
Following a Plume
• Run the model with only biomass burning CO • Follow the highest concentration of CO for the ‘centre’ of
the plume
Introduction Plume Tracking Chemical Pathways Summary
Ozone in Wildfire Plume
16th July 17th July 18th July 19th July Time (GMT)
Destruction over night (in N. America)
Peak ozone midday
Rapid destruction + jump in plume tracking (not perfect…)
Minor fluctuations - other factors coming into play like biogenic sources?
Ozo
ne (p
pb)
0 40
80
Introduction Plume Tracking Chemical Pathways Summary
Production of Ozone
NO2 + hv
O3
NO + O*
O* + O2
99.9% of all ozone production in the plume
=
NO2 is the controlling factor - what reactions create NO2?
Introduction Plume Tracking Chemical Pathways Summary
Production of NO2
Contribution to NO2
86.7 % NO + O3
Others 13.3%
89 reactions in GEOS-Chem that produce NO2
Introduction Plume Tracking Chemical Pathways Summary
Production of HO2
O3
NO2 + hv
HO2 + O3
CO + OH
Contribution to HO2 Reaction Pathway
99.9 %
4.9%
29.4%
1.4% of ozone was created through this chemical pathway
Introduction Plume Tracking Chemical Pathways Summary
% C
ontri
butio
n
Time since emission
Production of NO2 - Hourly
16th July 17th July 18th July 19th July
0 10
0 50
Introduction Plume Tracking Chemical Pathways Summary
Next Steps
• Look further down the chemical pathways - what species are the big players?
• Do the same for loss reactions • When do different emissions have the biggest
impact? • What does this mean for total reaction yield, not
just percentage contribution?
Delve Deeper…
1
Introduction Plume Tracking Chemical Pathways Summary
Next Steps
• Change biomass, biogenic and anthropogenic emissions one by one and in tandem
• Change in ozone will be tiny - will the change in reactions be larger?
• Do different emissions have different effects at later stages in the plume?
Sensitivity Analysis
2
Introduction Plume Tracking Chemical Pathways Summary
Next Steps
• How will increasing the number of species & reactions impact the ozone?
• Will an updated mechanism change what reaction pathways are important?
• Is the current mechanism getting the right answer for the wrong reasons?
A New Chemical Mechanism (CRI)
3
Introduction Plume Tracking Chemical Pathways Summary
Summary
• BB has been found to cause both production and loss of ozone
• Examining the chemical pathways along a plume track
can give us new insights
• We can quantify the reaction yield from certain pathways - eventually from volume of emission to amount of ozone
• We can determine when the different emission are most
important as the plume travels