5 ambient concentrations; visibility; ambient concentrations and deposition fluxes of several hazardous air pollutants, including mercury; deposition fluxes of nutrient nitrogen; and deposition of acids such as sulfuric acid and nitric acid.
Mercury is a hazardous air pollutant.
Obviously, a president's ambition, judgment, temperament, integrity, and ways of relating with other people (among other psychological qualities) bear greatly on how he will govern--at least as greatly as whatever election-year stands he stakes out on the issues of policy.