91.   State officials are watching the talks closely, because the states are under orders from EPA to control the emissions of nitrogen oxides and other unhealthful air pollutants.

92.   Sulfur dioxide and nitrogen oxide are the pollutants that form acid when they mix with clouds.

93.   Sunlight reacts with hydrocarbons and nitrogen oxides emitted by automobiles and industries to produce ozone.

94.   SUVs emit up to three times more nitrogen oxides, a key precursor to smog, than passenger cars.

95.   Sulfur in fuel clogs emission controls on trucks and buses, so they are prodigious producers of soot and of nitrogen oxides, which cause smog.

96.   That is double the nitrogen oxides wafting into the air from traffic and smokestacks in Washington.

97.   That represents an amount that is about one-third the limit of emissions for nitrogen oxide, the chemicals causing smog.

98.   That is more than all the nitrogen oxides wafting into the air from traffic and smokestacks in Washington.

99.   The agreement with the Weld Administration, set to be announced Friday, limits the amount of nitrogen oxide that utilities and other firms can release to the air.

100.   The bill allows Alcoa to make substantial reductions in emissions of nitrogen oxides but to forgo reductions of sulfur dioxide.