A control strategy related to air quality is a set of specific techniques and measures identified and implemented to achieve reductions in air pollution to attain an air quality standard or goal.
On this page:
- Considerations in designing an effective control strategy
- Controlling sources of pollution
- Need for regional or national controls in addition to local controls
- What are the steps to developing a control strategy?
Considerations in designing an effective control strategy
- Environmental: factors such as ambient air quality conditions, relevant meteorological conditions, location of the emissions source, legal requirements, noise levels, and any ancillary pollution from the control system itself.
- Engineering: factors such as pollutant characteristics (such as abrasiveness, reactivity and toxicity), gas stream characteristics, performance characteristics of the control system, and adequate utilities (for example, water for wet scrubbers).
- Economic: factors such as capital cost, operating costs, equipment maintenance, equipment lifetime, and administrative and enforcement costs.
Pollution prevention approaches to reduce, eliminate, or prevent pollution at its source, should be considered. Examples are to use less toxic raw materials or fuels, use a less-polluting industrial process, and to improve the efficiency of the process.
The Clean Air Technology Center serves as a resource on air pollution prevention and control technologies, including their use, effectiveness and cost. Examples are mechanical collectors, wet scrubbers, fabric filters (baghouses), electrostatic precipitators, combustion systems (thermal oxidizers), condensers, absorbers, adsorbers, and biological degradation.
Controlling emissions related to transportation can include emission controls on vehicles as well as use of cleaner fuels.
Economic incentives, such as emissions trading, banking, and emissions caps can be used. These strategies may be combined with the "command-and-control" type regulations which have traditionally been used by air pollution control agencies.
Air pollution does not recognize geographic boundaries. Emissions of sulfur dioxide (SO2) and nitrogen oxides (NOX) can react in the atmosphere to form fine particle (PM2.5) pollution. Similarly, NOX emissions can react in the atmosphere with volatile organic compounds (VOC) and sunlight to create ground-level ozone pollution. These pollutants can travel great distances affecting air quality and public health locally and regionally in areas downwind.
For this reason, control strategies to improve air quality in local areas need to include control measures that are mandated and implemented on a state, region-wide or national basis, in combination with local control measures. In general, regulations established by the national government tend to have the widest application, which can minimize boundary and economic competition issues.
In the United States, the Clean Air Act requires that each state’s implementation plan contain provisions to prevent the emissions from the facilities or sources within its borders from contributing significantly to air quality problems in a downwind state. Learn more about the approach in the United States to address interstate air pollution transport.
What are the steps to developing a control strategy?
- Determine priority pollutants. The pollutants of concern for a specific location will be based on health effects and the severity of the air quality problem in that area.
- Identify measures to control sources of pollution.
- Develop a control strategy and plan that incorporates the control measures. The written plan should include implementation dates. The plan will need to include reference to the requirements that owners or operators of emission sources will need to undertake to reduce pollution contributing to the air quality problems.
Compliance and enforcement programs are also very important to include. These programs help owners or operators of sources understand the requirements, as well as the actions that environmental authorities can take if the sources don’t comply.
- Involve the public. Invite input from the regulated community and others, including the general public when developing the control strategy. This early consultation reduces later challenges and can help streamline implementation.
Governments getting starting in managing air quality should focus first on obvious sources of air pollution and the quickest means of controlling air emissions. More sophisticated and comprehensive strategies can be developed over time. The goal for all control strategies is to achieve real and measurable air emission reductions.
In the United States, control strategies to meet and maintain the national ambient air quality standards are developed by state governments. State governments adopt control measures through their legislative process and include them in state implementation plans, which need to be submitted and approved by EPA. The control measures are described and included in the plan. Control measures that are part of an approved state implementation plan can be enforced by either the state or the national government. Learn more about state implementation plans.
The Control Strategy Tool supports the assessment of emission reductions and engineering costs for control strategies.
Learn about reducing emissions of hazardous air pollutants in the United States.