The Act is enacted to control air pollution, maintain the living environment and public health and enhance the quality of life.

The competent authority referred to in the Act shall be the Environmental Protection Administration, Executive Yuan at the level of central government, the municipal government at municipality level, and the county (city) government at county (city) level.

Terms used in the Act are defined as follows:
1.Air pollutants: They refer to airborne substances sufficient to jeopardize directly or indirectly public health or the living environment.
2.Pollution sources: They refer to physical or chemical operating units that emit air pollutants. Pollution sources are classified as follows:
(1)Mobile pollution sources: They refer to the pollution sources that are able to change location in terms of their own power.
(2)Stationary pollution sources: They refer to the pollution sources other than mobile pollution sources.
3.Motor vehicles: They refer to vehicles traveling on a roadway by their own power and not dependent on rail or electric power systems, including motorcycles.
4.Living environment: It refers to property, animals and plants and their dependent environments that have a close relationship with the lives of humans.
5.Emission standards: They refer to the maximum concentration or the total quantity allowed for air pollutants or the emissions allowed per unit of raw materials, fuels or products.
6.Air quality standards: They refer to the concentration limits for air pollutants in outdoor air.
7.Air pollution control zones (hereinafter referred to as control zones): They refer to all classes of control zones delineated based on the demands placed upon air quality by land use within a region or in accordance with current air quality conditions.
8.Nature protection and conservation areas: They refer to ecological conservation areas, nature reserves, wildlife preserves and national forest preserves.
9.Cap and trade: It refers to the restrictive measures imposed to control the total allowable emissions of air pollutants within a specific area in order to improve air quality effectively.
10.Cap-and-trade zones: They refer to the areas delineated based on topographical and meteorological conditions and in accordance with the total quantity control requirements.
11.Control technologies: They refer to pollutant reduction technologies adopted to reduce air pollutants from stationary pollution sources. Major categories of control technologies are stated as follows:
(1)best available control technology: It refers to the commercialized technology that provides the greatest available reduction in pollutant emissions and that pollution sources, after taking into account energy, environmental and economic impacts and other costs.
(2)lowest achievable emission rate control technology: It refers to the technology adopted to reduce air pollutant emissions from pollution sources to the lowest achievable emission rate using scientific methods after the impact on energy, environment, economy and health is considered.
12.Idle: When the engine of a motor vehicle is operating continuously while the vehicle is stationary.
13.Air quality maintenance zones: Air quality maintenance zones refer to the specific zones where mobile pollution sources are restricted or prohibited for maintenance of air quality.
14.Volatile organic compound containing chemicals: The chemicals refer to any materials, products or articles containing volatile organic compounds.

Competent authorities at all levels may designate, commission or delegate dedicated organizations or agencies to perform tasks related to air pollution research, training and control.