I don't know if it's that complex Bjorn. People instinctively know when their in a filthy polluted environment 90% of the time. Sure there's the unknowns like Flint Michigan lead levels in the water, but more often we know pollution when we see it and don't need graphs, charts or power points to tell us. One pic from China, human shit and needles in San Fransisco or trash floating in the ocean and we know.
Where people fool themselves is normalcy bias. People go to the country and say, wow the air is clean here, but don't wonder, does that mean my daily urban environment is polluted.