Implications of new suspended particle standards for the cement industry

The US EPA has promulgated new ambient air quality standards for PM₁₀ and PM_2.5 (particles with aerodynamic diameters less than (10) and 2.5 microns, respectively). The new PM₁₀ standards require 3-year averages of 99th percentiles for 24-hour PM₁₀ mass to be less than 150 μg/m³, in place of the maximum measured concentration, and three-year averages in place of annual averages to be less than 50 μg/m³. The acceptable PM_2.5 levels are strict for the three-year annual average at 15 μg/m³; however, compliance will be determined by a spatial average from several monitors in populated areas rather than from a single monitor. The three-year 98th percentile average for 24-hour PM_2.5 is 65 μg/m³ ; this standard will probably be easier to attain than the annual average. Sulfur dioxide, oxides of nitrogen, ammonia, and heavy hydrocarbon gas emissions can change into ammonium sulfate, ammonium nitrate, and carbon particles, and these emissions will be more highly regulated. “Fence line” sites located to determine maximum impact from a facility will not be favored for annual PM_2.5 compliance monitoring. For the cement primary particles and precursor gases from milled materials and fuel combustion in kilns, clinker coolers, finish mills, raw mills, coal mills, silos, bagging operations, and loadout areas will become the pollutants under greatest scrutiny in nonattainment areas. Exhaust emissions from haul trucks and delivery vehicles will also be larger relative contributors to PM_2.5 than they were to PM₁₀