List of Figures

iv

List of Tables

iv

Acronyms and Abbreviations

v

1.0

Executive Summary

1

2.0

Introduction

2

2.1

WMATA’s Clean Bus Choices

3

2.2

Emission Testing of WMATA’s CNG and Diesel Buses

3

3.0

Test Vehicle Description

5

4.0

Test Methodology

8

4.1

WVU Laboratory Description and Analysis of Emissions

8

4.2

NREL Laboratory Description and Analysis of Unregulated Emissions

10

4.3

Test Cycle

13

5.0

Test Cycle

13

6.0

Results and Discussion

14

6.1

Oxides of Nitrogen

15

6.2

Particulate Matter

18

6.3

Carbon Monoxide

20

6.4

Hydrocarbons

20

6.5

Carbon Dioxide

20

6.6

Fuel Economy

23

6.7

Carbonyl Emissions

25

7.0

Conclusions

27

7.1

Regulated Emissions and Fuel Economy

27

7.2

Carbonyl/Toxic Emissions

31

7.3

Overall Conclusions

31

8.0

References

31

Appendix A

Gas Chromatography Results

33