Exposure to air pollution is linked to an increase in violent crime
I grew up in a part of the US that  some of the most polluted air in the country, back in the 70s and 80s.  I recall waking up on a particularly clear day and being shocked by a mountain in the background, not realizing how close we lived to the mountains.  I also recall feeling depressed about the continually yellow sky.  While there may be a physiological effect of air pollution, I'm certain there is also a strong psychological effect, which could explain the immediate effects described in the article.