Pastels offer a balance between painting and drawing and I have found them suitable for plein air work without all the fuss with brushes, water, easels and such.  Smaller sheets are taped to a drawing board and you are ready to go. 

 

The colors can be rich or subdued.   Various papers are used for the different effects desired.  But you have to be careful with the layering and blending.  Some papers can only receive a certain amount of pastel before reaching the saturation limit. 

 

Remember coloring with crayons?  There is a sense of fulfillment that comes with pastels not unlike those early crayon drawings that ended up on the refrigerator.  It is a sensuous medium and you are working with pure color. Lots of possibilities!