comparison of gas concentration

8/14/2019 Comparison of Gas Concentration

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Comparison of Gas concentrationover Sacramento and Palmdale

Atul Lunawat

SARP 2009


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Overview

Background and Objective:

CFCs and HCFCs

Why Sacramento versus Palmdale?

Methodology:Onboard DC-8

Field work

The Chemistry lab

Results

Conclusion

Future Work

References


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CFCs

Developed in early 1930s.

Used in a variety of industrial, commercial and

household applications like:

Coolant in refrigeration units.

Aerosol propellants.

Electronic Cleaning Solvents.

Blowing Agents.


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CFCs are non-reactive and hence they tend to riseinto the stratosphere.

Why are CFCs bad?

Destruction of Ozone Layer.

Trapping of heat, contributing to Global Warming.

In 1973, this danger became clear, leading to

Montreal Protocol in 1987.

CFCs


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HCFC's have ozone depletion potentials around

0.01-0.1, so that during its lifetime a typical HCFC

will have destroyed 1-10% as much ozone as the

same amount of CFC. Since the HCFC's are more reactive in the

troposphere, fewer of them reach the stratosphere.

However, they are also more reactive in the

stratosphere, so they release chlorine more quickly.

The short-term effects are therefore larger than one

would predict from the steady-state ozone depletion

potential.

How safe are HCFCs???


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Gases I have selected to study

H-1211 (Bromochlorodifluoromethane) Used in Fire Extinguishers.

HCFC-141b (1,1-Dichloro-1-fluoroethane)

Mainly used as refrigerant.

HCFC-142b (1-Chloro-1,1-difluoroethane)

Mainly used as chemical intermediate and blowing agent.

HFC-134a (1,1,1,2-Tetrafluoroethane)

Mainly used as refrigerant.

C2Cl4 (Tetrachloroethylene)

Used for fabric dry cleaning.

HCFC-22(Chlorodifluoromethane)


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Chlorodifluoromethane

Colorless gas better known as HCFC-22 or R-22.

Once commonly used as a propellant and in air

conditioning applications as an alternative to CFC-11.

ODP = 0.055 and GWP = 1700

From January 1st, 2010, it will be illegal to import,produce, or sell R-22 for use in new equipment or pre-

charged in new equipment.

In 2015, the production and no importing of HCFC-22 will

be limited to 10% of each country's 1989 consumption

level and in 2020, production and importing of HCFC-22

will be illegal.

Re-use of recovered HCFC-22 will be permitted until

2030.


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Why Sacramento versus

Palmdale???


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Sacramento

Capital of California. Seventh largest city with estimated population of

460,242.

It is the core culture and economic center ofSacramento Metropolitan area.

Cited as one of the ten most livable regions in

America in 2004.

Industries Transportation, IT, Construction,

Health-care


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Palmdale

Small city located in the north-east reaches of

Los Angeles County, California.

As of January 1, 2009, the California state

department of finance estimates that Palmdale

has a total population of 151,346.

Industries Aerospace, manufacturing.


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Methodology

Data Gathering:

Collected air samples on board DC-8 at various

altitudes and lat-long.

Collected ground air samples.

Data Analysis:

5 column system the GCs.

Mass Spectrometry.

Chromeleon.


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University of California, Irvine 5-Column System


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Average Data Comparison

H-1211

HCFC-141b

HCFC-142b

HCFC-22

HFC-134a C2Cl4

Sacramento 4.67 26.65 29.21 316.50 97.59 13.57

Palmdale 4.43 29.03 24.67 247.40 78.61 6.68Background 4.57 21.82 21.54 196.91 45.96 1.64

All values are in pptv


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Comparison of Averages of Sacramento,,Palmdale and Background data


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Comparison of Delta values ofSacramento and Palmdale


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Back Trajectories

Palmdale seems much more influenced by the

LA region.

Sacramento appears to import pollutants more

from the east.


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Industries in Los Angeles

Steel Fabrication is the second largest industry.

Los Angeles is a major producer of:

Furniture fixtures

Petroleum products and Chemicals

Print material

Rubber goods

Electronic equipment

Glass, Pottery, Ceramics and Cement products.


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Conclusion

Gas concentration in Palmdale is higher than

Sacramento due to its close proximity to high

population city like Los Angeles and heavyindustrialization.

HCFC-22 concentration alone is higher than the

sum of remaining gases indicating possible leak

from a chemical plant.

Palmdale air is not affected by transport from

Sacramento.


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Future Work

Study of the industries around Palmdale and Los

Angeles to verify the cause of high HCFC-22levels.

Study the gas concentration in Palmdale with

different meteorological conditions, so as to

verify the source of Palmdale gas concentration.


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References

http://www.centerforsustainability.org/

http://stason.org/

http://www.wikipedia.org/

The Montreal Protocol on Substances that Deplete

the Ozone Layer. UNEP, 2000.

http://www.city-data.com


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Acknowledgements

Dr Sherwood Rowland Dr Don Blake

Dr Melissa Yang

Dr Alexandra Novak

The Whole Air Sampling team

Rowland/Blake research group

NASA

Everyone else responsible formaking SARP possible.


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Thank You

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