Air Pollution Control

What Does Air Pollution Control Mean?

Air pollution control is the process of limiting or eliminating atmospheric emissions that are harmful to humans, animals, and the environment. Airborne pollutants can result from combustion, industrial processes, and natural events like forest fires or volcanic activity.

Although airborne contaminants can also be an issue indoors, air pollution control specifically refers to measures aimed at protecting outdoor air quality.

Safeopedia Explains Air Pollution Control

Air pollutants are a vast category that include, among others:

• Soot, ash, and dust
• Carbon monoxide (CO)
• Sulfur dioxide (SO₂)
• Nitrogen dioxide (NO₂)
• Pollen
• Asbestos

The major air pollutants each have specific emission control regulations. Additional regulations have been enacted to control greenhouse gasses, such as chlorofluorocarbons, methane, and nitrous oxide.

Techniques for Air Pollution Control

Harmful particulates and gasses in the air can be controlled in various ways, including:

• Combustion – Exposing organic gaseous and vapor air pollutants to catalytic combustion can convert them to less harmful byproducts like carbon dioxide and water
• Absorption – Air containing gaseous pollutants are passed through a scrubber containing a liquid that absorbs the pollutants
• Adsorption – Adsorbent filters block contaminants from escaping into the air
• Dust control measures - Dust, ash, and soot can be controlled by various means, such as filters, wet scrubbers, and electrostatic precipitators

Air Pollution Control Devices

There are two main types of air pollution control devices: those that control the amount of particulate matter being released into the atmosphere and those that control acidic gas emissions.

Particulate Control Devices

• Fabric filters that trap the particulate matter in smoke and prevent them from escaping through smokestacks
• Electrostatic precipitators that use static electricity to remove soot and ash from exhaust fumes
• Cyclone separators that use the difference of inertia between gas particles and larger particulate matter to cause them to separate, with gas particles moving up while larger particles drop to the bottom of the device

Gas Control Devices

• Incineration converts volatile organic compounds (VOC) into carbon dioxide and water in a container known as the afterburner
• Scrubbers remove harmful materials from industrial exhaust, either by means of a physical filter (dry scrubbers) or by initiating a chemical reaction (wet scrubbers)