Atmospheric Environment 37 (2003) 4747–4755

Atmospheric Environment 37 (2003) 4747–4755

Analysis of methyl tert-butyl ether in the atmosphere and implications as an exclusive

indicator of automobile exhaust

Speaker : Snow

Octane-enhancing gasoline additive

Enhancing the combustion efficiency

1996, U.S Santa Monica contamination

MTBE

Reduce CO、 Hydrocarbons、 O3

Reduce possibility of explosion

Contamination

Quick diagnosis for emission source

X

Y

Y - X

Y

Field mission

Site I : Hsinchu, Guangfu Rd.

Site II : Hsinchu, Baoshan Rd.

Site III : Kaushiung city

濃縮 分離 偵測

(a)

(b)

Preconcentrator

Trap volume

190 ml

PLOT

DB-1

Instrumental

FID MS scan range

10-180

Chromatogram of C2 – C4

GC-FID

1. Ethtane

2. Ethylene

3. Propane

4. Propene

5. Ethyne

6. Isobutane

7. n-butane

Chromatogram of C4 - C10

1. Isobutane

2. Isopentane

3. MTBE

4. 2-methylpentane

5. Benzene

6. Toluene

7. Ethylbenzene

8. m,p-xylene

9. Styrene

10. o-xylene

11. 1,2,4-trimethylbenzene

GC/MS

Standard

TIC

real sample

TIC

real sample

SIM

GC/MS analysis

Precision & MDL - I

Precision & MDL - II

Diurnal variation – site I

Validation

NMHCs/MTBE Site I Site II

Ethene 4.7 4.9

Benzene 1.0 1.0

Toluene 4.4 4.9

Ethylbenzene 0.9 0.8

o-Xylene 1.4 1.1

Correlations of VOCs & MTBE – site III

Chemical & physical removal

Chemical removal : photochemical reaction

Physical removal : wet deposition

Ratio of longer-lived VOCs to MTBE – site I

Analytical system was established to measure VOCs and MTBE simultaneously without interference from water.

In urban areas, MTBE was highly correlated with most VOCs.

Using VOCs/MTBE can quickly diagnosis VOCs emissions source.

MTBE can be a useful exclusive indicator of traffic emissions.

Conclusion