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