ScienceDaily: A thick blanket of yellow haze hovering over Houston as a result of chemical pollution produced by manufacturing petroleum products may be getting a little bit thinner, according to a new study. But the new findings — which have implications for petrochemical-producing cities around the world — come with a catch, says a team of scientists from the Cooperative Institute for Research in Environmental Sciences, or CIRES, a joint institute of the University of Colorado at Boulder and …