Acknowledgments.

1. Background and Objectives.

2. Sampling and Averaging Time Definitions.

3. Effect of Averaging Time on Mean Calculations.

4. Concentration Fluctuation Modeling.

5. Probability Distributions.

6. Release Height and Source Size Effects on Fluctuation Intensity.

7. Source Density Effects on Fluctuations.

8. Buildings and Obstacles.

9. Threshold Crossing and peak Levels.

10. Framework for an Operational Model.

Appendix A. Averaging and Sampling Time Effects on Plume Spread Velocity and Concentration Fluctuations.

Appendix B. Peak Values and Threshold Crossing Probability.

Appendix C. Eulerian and Lagrangian Turbulence Scales.

References.

Nomenclature.

Index.