euphore chamber in spain (204m 3` x 2) swiss indoor chamber (27m 3 )
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New Indoor and Outdoor Smog Chambers
Costs, advantages/disadvantages and types of things one can study
• EUPHORE Chamber in Spain (204m3`x 2)• Swiss Indoor Chamber (27m3)• Caltech indoor chamber (28m3• EPA-RTP indoor chamber indoor (14.5m3)• UNC-outdoor chamber (135m3x2)• UCR-CERT indoor (90m3x2)
The European PhotoreactorEUPHORE (1996)
• Largest outdoor chamber (204 m3)• FEP film with a thickness of 0.127 mm (80%
transmission)• Positive pressure (100-200 Pa)• State of the art instrumentation
DOAS (O3, NO2, HCHO, HONO) , long-path FT-IRTDL (tunable diode laser)
This image shows one of the two chambers of EUPHOR
The European PhotoreactorEUPHORE (1996)
• K.H. Becker / Project Co-cordinator becker@physchem.uni-wuppertal.de
• J. Hjorth jens.hjorth@jrc.it • G. Laverdet laverdet@cnrs-orleans.fr • M.M. Millán millan@ceam.es • U. Platt pl@uphys.uni-heidelberg.de
Caltech new Indoor chambers(Cocker and Seinfeld et al, ES&T 35, 2594,2001)
• Two 28m3 meters• 2 ml FEP Teflon wall• Controlled aerosol injection system• Indoor lights
William Carter aerosol chambers
• two collapsible 90m3 FEP Teflon film reactors inside an outer enclosure.
• Solar radiation is simulated with either a 200kW Argon arc lamp or multiple black lamps.
• Collapsible system, positive 5 pa, Outer enclosure flushed with clean air to reduce input of dirty air from outside; temp controlled from 5-45oC
• mechanism evaluation data for experiments with NOx levels as low as 2 ppb
New UNC outdoor aerosol dual chamber
• Quonset Hut design; 270 m3 FEP Teflon film chambers.
• Natural sunlight • Exchange rate with outside air 0.5 to 1.5%/hour• Particle half-live of 17 hours• Design permits chamber walls to be easily washed
Dual 270m3 chamber fine particle t 1/2 >17 h
New UNC aerosol smog chamber
Major costs for any chamber system
• NOx, O3 $24,000• 4 GC and GCMSs 200,000• 6 nm to 900 nm particles 85,000• 0.3 to 5 um particles 25,000• Data system 3,500• Light and Dew point 6,000• Flow meters, etc 10,000• 6 place balance 12,000• Clean air generator 20,000• Denuders and filter holders 10,000• Total = ~$ 400,000• Build a new chamber ~50,000-100,000
Need an analytical and an modeling group
•
Research Issues that can be studied in Environmental Chambers
• Chemical mechanisms• Product studies• Effects of light, temperature and
water vapor• Generate data for modeling studies
– Simple compounds – Complex mixtures
• Gases and particle interactions
Problems with Environmental Chambers
• Wall effects
• Care is needed to extend results to the atmosphere.
• Wall effectsAldehydes, HONO can off gas from the walls
wet walls adsorb more aldehydes and NOX
outer sheath of clean air
purchase a “clean batch” of Teflon film
have a chamber design that permits cleaning
run characterization tests before and after cleaning (O3 decay)
What are some historical uses for Environmental Chambers
• Test and develop gas phase chemical mechanisms
• Develop product information and yields
• Reactivity
• Evaluate aerosol formation– Aerosol products– Aerosol kinetic mechanisms
The Chamber had two sides
Or Darkness 300 m3 chamber
Teflon Film walls
The Chamber had two sides
Or Darkness
Formaldehyde
propylene
300 m3 chamber
Teflon Film walls
The Chamber had two sides
Or Darkness
Formaldehyde
propylene
300 m3 chamber
Teflon Film walls
The Chamber had two sides
Or Darkness
Formaldehyde
propylene
300 m3 chamber
Teflon Film walls
NO &NO2
Example experiment with the following chamber concentrations:
• NO = 0.47 • NO2 = 0.11 ppm• Propylene = 0.99 ppmV• temp = 15 to 21oC
Solar Radiation Profile
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
cal c
m-2
min
-1
6 8 10 12 14 16 time in hours
TSR
Example Mechanism NO2+ hNO + O. k1 keyed to sunlight
O. + O2 --> O3 k2
O3 +NO2 --> NO + O3 k3
H2C=O + h --> .HC=O + H. k4 keyed to sunlight
H. +O2 --> HO2. k5
HO2. + NO --> NO2+OH. k6 (fast) OH.+ C=C ---> H2C=O + HO2
+ H2COO. k7
• dNO2/dt = -k1[NO2]; NO2=-k1 [NO2] t
Photochemical System
0
0.1
0.2
0.3
0.4
0.5
0.6 pp
m
10 11 12 13 14 15 time in hours
NO-data O3-mod NO2-data
O3-data NO-mod NO2-mod
NOx-O3: model vs. data
PAN
NO2O3
NO
NO2
Photochemical System
0
0.2
0.4
0.6
0.8
1
1.2
ppm
V
10 11 12 13 14 15 Time in hours
Propylene: data vs. model
Studying AEROSOLS IN Chambers
• Ambient data often guides experiments
• Our understanding of aerosol formation is ~20 years behind gas phase chemistry
PM10 Chemical Characterization in Beijing Xiao-Feng, Min Hua, Ling-Yan Hea, Xiao-Yan
Tang, Atmos. Environ. 39 (2005) 2819–2827
Characteristics of carbonaceous aerosols in Beijing, ChinaYele 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, were the major sources of the aerosol pollution in Beijing.
• Mineral aerosol from outside Beijing accounted for 79% of the total PM10 minerals and 37% of the PM2.5 in winter. It was 19% and 20% in summer
Characteristics of carbonaceous aerosols in Beijing, ChinaFengkui 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%.
Characteristics of carbonaceous aerosols in Beijing, ChinaYele Suna, Guoshun Zhuang, Ying Wang, Lihui Han, Jinghua Guo, Mo Dan, Wenjie Zhang, Zifa Wang, Zhengping Hao, Atmos, Environ. 38 (2004) 5991–6004
• PM2.5/PM10 ratios were 0.45–0.48 in summer and 0.52–0.73 in winter
• in winter. SO4 , NO3, NH4, OC,crustal matter, and EC were the six dominant species
Can we chemically and kinetically model Secondary Organic Aerosol Formation???
• Numerical fitting• Semi-explicit
From a modeling perspective Equilibrium Organic Gas-particle partitioning provides a context for addressing SOA formation
Gas/Particle Partitioning
particleand particleChemical nature of gasTemperature
Humidity
gas
Thermodynamic Equilibrium?
TSPCC
Kgas
partp
Cgas +surf Cpart
Kp will vary with 1/Po
Odum-Seinfeld Model SOA model
Y= MY= Moo / / HC HC
Y Y MK
K Mii
oi om i
om i oi
,
,( )1
- pinene- NOx experiments by OdumY Mo(g/m3)
1 0.012 1
2 0.028 8
3 0.056 22
4 0.067 34
5 0.081 38
6 0.116 83
7 0.122 94
Y MK
K M MK
K Moom
om oo
om
om o
1 1
1
2 2
21 1,
,
,
,( ) ( )
Y = M= Moo / / HC HC
-pinene
Y MK
K M MK
K Moom
om oo
om
om o
1 1
1
2 2
21 1,
,
,
,( ) ( )
How is this done?
1 = 0.038, Kom1= 0.17
2 = 0.326, Kom2 = 0.004
Overall kinetic Mechanism
• links gas and particle phase rate expressions
gas phase reactions min-1 or ppm-1 min-1
1-pinene + O3 .4 Criegee1 + .6 Criegee2 1.492 exp-732/T2. Criegee1 .3 pinacidgas + .15 stabcrieg1 + .8 OH + .5 HO2 + .3 pinaldgas + .25 oxy-pinaldgas + .3 CO 1x106
3. Criegee2 .35 crgprod2 + .5 oxy-pinaldgas +.35 HCHO + .15 stabcrieg2 +.8 OH + .5 HO2 1x106
4. stabcrieg1 + H2O pinacidgas 6x10-3
10. oxy-prepinacid +HO2 oxy-pinacid 677 exp1040/T16. pinacidgas {walls} 4x10-7 exp2445/T
partitioning reactions22. stabcrieg1 + pinaldgas seed1 29.5,25. pinacidgas + seed1 seed1 + pinacidpart 29.8,34. diacidgas + pinacidpart --> pinacidpart + diacidpart 68,35. diacidpart diacidgas 3.73x1014 exp-10285/T44. diacidpart {walls} 0.0008,
Particle Phase reactions
particle
C=OO
cis-pinonaldhyde
C=OO
polymers
Gas phase reactions
Particle Phase reactions
particle
C=OO
cis-pinonaldhyde
C=OO
polymers
Gas phase reactions
Particle Phase reactions
C=OO
cis-pinonaldhyde
C=OO
polymers
Gas phase reactions
Chemical System
-pinene
+ NOx+ sunlight + ozone----> aerosols
0
0.2
0.4
0.6
0.8
1
ppm
V
9 9.2 9.4 9.6 9.8 10 Time in hours
Gas Phase -pinene and O3data and model
-pinene
MODEL
Warm high concentration experiment
MODEL
Warm high concentration experiment
0
1
2
3
4
5
9 10 11 12 13 time in hours
A
model
Filter Data
Reacted -pinene
mg /
m3
Other Temperature Conditions
0.82 ppmv -pinene + 0.60 ppm O3(295K)
0.60 ppmv -pinene + 0.65 ppm O3 (284K)
0.35 ppmv -pinene + 0.25 ppm O3 (295K)
0.88 ppmv -pinene + 0.47 ppm O3(269K)
Daytime systems
0.95 ppm -pinene + 0. 44ppm NOx
O3NO
NO2
NO2
model
data
Time in hours EST
ppm
V
Gas phase pinonaldehdye
OO
mg/
m3
Time in hours EST
Particle phase
model TSP
mg/
m3
Particle phase
model TSP
mg/
m3
Measured particle mass vs. model
data
Time in hours EST
Indoor vs. Outdoor chambers: Advantages and disadvantages• Indoor chambers
– More controlled conditions– It is possible to change temperatures– Conduct more experiments– Difficult to maintain constant light conditions– Need a large building for a large chamber– Can be used in a dynamic mode to generate large
samples for product analysis
Indoor vs. Outdoor chambers: Advantages and disadvantages
• Outdoor chambers – Can not control temperature– Temperature changes during the day– Conduct fewer experiments– Uses real sunlight – Large chambers can be used for longer
simulations
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