Which of the following methods helps in controlling emissions in power plants?

Implementing air quality control systems is an effective method for controlling emissions in power plants. These systems are specifically designed to reduce the release of harmful pollutants into the atmosphere. They can include various technologies such as scrubbers, which remove sulfur dioxide; selective catalytic reduction systems for nitrogen oxides; and particulate matter collectors like electrostatic precipitators. By utilizing these technologies, power plants can significantly minimize their environmental impact and comply with regulatory standards regarding air quality.

Choosing to upgrade equipment to newer technology can also reduce emissions, but it is often not as direct or immediate as implementing specific air quality control systems. While using a single type of fuel may streamline operations, it does not inherently reduce emissions unless that fuel is cleaner than alternatives. Reducing maintenance schedules can lead to increased emissions due to potential inefficiencies and unsafe operating conditions, making this approach counterproductive.