This standard stipulates the emission limits of 33 kinds of air pollutants, and also stipulates various requirements in the implementation of the standard. In China's existing national air pollutant discharge standard system, in accordance with the principle of non-intersecting implementation of comprehensive emission standards and industry emission standards, boilers implement GB13271-91 "Boiler Air Pollutant Emission Standards", and industrial furnaces implement GB9078- 1996 "Emission Standards of Air Pollutants for Industrial Furnaces", thermal power plants implement GB13223-1996 "Emission Standards of Air Pollutants for Thermal Power Plants", coke ovens implement GB16171-1996 "Emission Standards of Air Pollutants for Coke Ovens", and cement plants implement GB4915-1996 "Emission Standards of Air Pollutants for Cement Plants", GB14554-93 "Emission Standards for Odor Pollutants" for the discharge of odorous substances, GB14761.1~14761.7-93 "Emission Standards for Air Pollutants from Automobiles" for automobile emissions, and GB14621 for motorcycle exhaust -93 "Motorcycle Exhaust Pollutant Emission Standards", other air pollutant emissions are subject to this standard. The industry-specific national air pollutant discharge standards issued after the implementation of this standard will no longer implement this standard for the pollution sources specified in its scope of application. This standard applies to the management of air pollutant emissions from existing pollution sources, as well as the environmental impact assessment, design, completion acceptance of environmental protection facilities of construction projects and the management of air pollutant emissions after they are put into operation.