The last four years, hikers have had a difficult time finding negative ions. These are commonly found under waterfalls and offer numerous health benefits.
Fortunately, this winter it is much easier to find waterfalls and the negative ions they create. One great place for hiking and waterfalls is Mt. Tam. Almost every valley has a small stream feeding into a larger one. Zig zagging up the hill is great exercise and offers numerous resting places to enjoy pool and drop waterfalls!