ENERGY POLICY and AIR QUALITY Combustion Sources emit: –Primary PM, comprised mainly of elemental and organic carbon that forms from the carbon in fuel –Precursor gases that are the main components of secondary PM: SOx which can form sulfates NOx which can form nitrates (To a lesser extent ammonia, commonly a by-product of NOx control equipment, which can neutralize both nitrate and sulfate to form salts in the solid phase)
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