The role of halocarbons in the climate change

The Role Of Halocarbons In The Climate Change:Malaysia

observation

Mohd Shahrul Mohd Nadzir (PhD)Centre for Tropical System & Climate Change (IKLIM)

National University of Malaysia (UKM)

Halocarbons•Halocarbons are the substances responsible for the hole in the

ozone layer. Though they have been heavily regulated, they are still responsible for some amount of global warming.

• Why do I care? Halocarbons are more under control than most greenhouse gases, but they are still having an impact on climate.

• Halocarbons are mostly man-made gases consisting of both carbon and at least one of the halogens (fluorine, chlorine, iodine, and bromine). The majority of them fall into the category of Chlorofluorocarbons or CFCs. These gases are most well known for their ability to destroy stratospheric ozone, but they are also very strong greenhouse gases. On average they are thousands of times more efficient at warming than CO2. Fortunately, their concentrations are very small, so their powerful greenhouse effect is limited. Their atmospheric lifespan can range from 1 to 50,000 years.

• Chemical compounds containing carbon atoms, and one or more atoms of the halogens chlorine (Cl), bromine (Br), or iodine (I). Halocarbons include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and halons.

Halocarbons

• Also known as ozone-depleting substance (ODS), most ODSs are regulated by the Montreal Protocol.

•Catalytic destruction of ozone as below: X + O3 XO + O2……………..(1) Y + O3 YO + O2……………….(2)

XO + YO X + Y + O2………..(3)

Halocarbons

Long-lived Short-lived

Atm. Lifetimes~ hundreds of years Atm. Lifetimes~ weeks to months

CFC-11, CFC-12, CFC-113, CFC-114, CFC-115,

CCl4, Halon-1301 and CH3Cl

CHBr3, CH2Br2, CHBr2Cl, CHCl3,CH3I,CH3Cl

VSLS/VSLH

Common halocarbons in the atmosphere

CFCs –11 -12 -113 -13 -114 -114a -115

HCFCs -21 -22 -141b -142b -123 -124

HFCs -23 -134a -143a -152a -125 -227ea 32 PFCs CF4 C2F6 C3F8 c-C4F8 SF6 SF5CF3 SO2F2

Halons -1211 -1301 -2402 -1202

Bromocarbons CH3Br CHBr3 CH2Br2 CH2BrCl CHBrCl2 CHBr2Cl C2H5Br C2H4Br2 C3H5Br CF3CHBrCl Others?

Chlorocarbons CH3Cl CH2Cl2 CHCl3 CH3CCl3 CCl4 C2HCl3 C2Cl4 Iodocarbons CH3I C2H5I C3H5I CH2ClI Others? Sulphur Cmpds OCS CS2

Alkyl nitrates CH3ONO2 C2-C6 RONO2 Hydrocarbons Benzene Toluene n-butane

*Anthropogenic and Natural*

Sources of VSLS

• Many VSL are believed to be emitted naturally, tropical oceans represent a major source.

•Tropical Macroalgae (seaweeds) constitute an important source (Gschwend et al., 1985), an open ocean source related to phytoplankton has also been identified (Tokarczyk and Moore, 1994).

Sources??

Potential global importance of the Malaysian region

WHY MALAYSIA??

Distribution of algae in Malaysia

Emission scenario in Pyle et al., 2011

Bromoform concentration at boundary layer over tropical region-modelling result

OBSERVATION6 Years

Field Deployment

Locations of research areas

IOES Research stationBachok.

Tawau, Sabah

Danum Valley, SabahMMD GAW station

ILHAM Resort, Port Dickson

Schematic of the core μDirac gas chromatograph. The smaller schematics in the lower left show the Valco valve flow paths for the“inject” and “sample” positions.

MicroDirac Gas Chromatography-ECD

ECD Signal

Compounds measured• anthropogenic tracers:

C2Cl4 (lifetime ~3 months)

CH3CCl3 (~ 5 years)

• biogenic tracers (mostly marine sources):

CHBr3 (~3 weeks)

CH2Br2 (~ 5 months)

• anthropogenic / biogenic tracers (marine/terrestrial?):

CHCl3 (~6 months)

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Data coverage / sites

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GAW tower• One GC inlet always at 12m tower

height

• Other GC was mobile (80m tower height, downhill from GAW station, other forest sites, Kunak at coast)

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‘Down the hill’below canopy

inlet

CHBr3 and C2Cl4 Coast and Forest

Danum Valley(Tropics) & Tawau(Coastal)CHBr3 CH2Br2

CH2Br2

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CH2Br2 vs CHBr3Nov-Feb 09

0.01 0.1 1 10 1000.01

0.1

1

10

100 CH

2Br

2

Linear Fit CH2Br

2

Log[

CH 2B

r 2]ppt

Log[CHBr3]ppt

Nov 08

0.01 0.1 1 10 1000.01

0.1

1

10

100 CH

2Br

2

Linear Fit CH2Br

2

Log[

CH 2B

r 2]ppt

Log[CHBr3]ppt

Dec 08

0.01 0.1 1 10 1000.01

0.1

1

10

100

CH2Br

2

Linear Fit CH2Br

2

Log[

CH 2B

r 2]ppt

Log[CHBr3]ppt

Jan 09

0.01 0.1 1 10 1000.01

0.1

1

10

100

CH2Br

2

Linear Fit CH2Br

2

Log[

CH 2B

r 2]ppt

Log[CHBr3]ppt

Feb 09

X-axis= log[CH2Br2] pptY-axis = log [CHBr3] ppt

CHCl3

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CHCl3

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CHCl3• annual cycle (OH seasonality) less

pronounced than C2Cl4

• interhemispheric difference

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• AGAGE PLOT:

CHCl3

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Cruise Observation

PESC Cruise in June/July 2009

Highest CHBr3 mixing ratios over SM Seaweed distribution

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Overall cruise measurement• CHBr3 and CH2Br2 levels are higher in the Straits than in any of the other parts of the cruise

• Suggestion of a decrease in concentration from heavily industrialised coast to open ocean; may be related to high population of phytoplankton and seaweeds at coastal areas, especially over the Straits of Malacca.

• Higher concentration at coast site compared to open ocean.

• High Chl-a concentration over coast contributed to the higher concentration.

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Mix

ing

ratio

(ppt

)

CHBr3CH2Br2CHBr2ClCHCl2BrCH2BrCl

CH2BrCl2%

CHCl2Br3%

CH2Br226%

CHBr2Cl5%

CHBr364%

CH2BrClCHCl2BrCH2Br2CHBr2ClCHBr3

EPSP Cruise in June/July 2009

Mean value = 8.6 ppt

Consclusion

• High mixing ratios of halocarbons increase from coastal and decrease approaching open ocean

• Emission of brominated halocarbons expected to be emitted from natural sources

• Tropical forest showed low mixing ratios of halocarbons• High biological productivity along strait of Malacca ~ 5ppt

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Summary / ongoing work / papers• Almost full coverage of Peninsular and Borneo Malaysia• Halocarbon Malaysia and global intercomparison?• Malaysia Antarctic Expedition Jan 2015.

Long Term measurement uDirac GC deployed:2 Malaysia sites1 Taiwan1 Australia1 New Zealand

Vacancies at IKLIM• We would like to invite applications for positions of Graduate

Research Assistant for project on 'Observations of biogenic VOCs and NOx their implications for tropospheric ozone and human health'.

EMPLOYMENT STATUS:FULL-TIME

• Please email your CV to shahrulnadzir@ukm.edu.my

THANK YOU