You guys should come by the Mission district or China Town or Lower Haight ( here in San Francisco ) or take public transit (any of the BART stations - 16th, 24th, Civic Center or Glen Park).
The foulest stench of excrement anywhere.
Some blame the Hispanic population and some blame the Hmong and others blame the street urchins. But I never expected to smell anything so odious in a major metropolis in the U.S.