Legal Question in Traffic Law in California

You could fight it: The Paul Buzzo Act only refers to roads, highways, and "adjoining areas." You could argue that the sidewalk in front of the club does not "adjoin" the street. Take photographs.

Your argument, that ash is "environmentally friendly," is interesting, but to advance the legal argument (for example that the Buzzo Act is unconstitutional because there is no rational basis for discriminating against people who protect the environment by littering cigarette ashes) would probably require substantial legal fees and costs of expert witnesses (ash experts) -- and then it's far from clear that the courts would buy your argument.