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Explora: Environment
and Resource Air pollution mitigation technologies

The findings were thematically categorized to highlight and other odorous compounds. Polluted air is passed
key concerns related to air pollution control technologies. through a biologically active medium, such as compost or
Where applicable, comparative data and statistics were soil, where microorganisms degrade the organic pollutants.
tabulated or referenced to support critical analysis. This method is particularly useful in wastewater treatment
plants and food-processing industries. Finally, low-NO
x
3. Technical strategies burners and combustion modification techniques aim to
Effective air pollution control requires an integrated minimize NO formation during combustion. By altering
x
combination of technological, regulatory, and societal conditions such as temperature, air-to-fuel ratio, and
approaches. These strategies aim either to prevent pollutant burner design, these approaches reduce NO emissions and
x
formation at the source or to capture and treat emissions are commonly applied in industrial boilers and furnaces.
before they are released into the atmosphere. Control Numerous methods and technologies are available for
measures vary depending on the type of pollutant, source controlling air pollution. The most effective approaches,
characteristics, and applicable environmental regulations. along with supporting data, are presented in the subsequent
This section provides an overview of key methods and subsections.
technologies for air pollution control, drawing on data
from previous research. 3.1. Emission control technology improvements
Electrostatic precipitators (ESPs) are widely used in Coal remains the primary fuel source for many power
power plants and industrial facilities to remove PM, dust, stations. While combustion of coal generates power, it also
and smoke. They operate by applying high-voltage electric releases substantial amounts of pollutants, including SO ,
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fields to charge airborne particles, which are then attracted nitrous oxide (N O), PM, and mercury. Coal-fired power
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to oppositely charged collector plates. The particles plants are major emitters of SO and NO . PM is primarily
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accumulate on the plates and are periodically removed. released from coal ash generated during combustion. The
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Baghouse filters, also known as fabric filters, are highly quality of the coal plays a significant role in determining
effective in capturing fine particulates such as PM and emission levels. Advancements in pollution control
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PM , as well as heavy metals. Contaminated air passes technologies can substantially reduce the concentration of
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through fabric filter bags that trap particles, allowing clean pollutants emitted into the atmosphere. These technologies
air to exit. Accumulated dust is periodically removed, must be both cost-effective and efficient in removing
making this system particularly efficient in industries pollutants. Table 1 summarizes findings from previous
such as cement, steel, and chemicals. Cyclone separators studies on various air pollution control techniques,
are typically used to eliminate coarse particle debris. In including their pollutant removal efficiencies, costs, and
a cylindrical chamber, centrifugal force drives heavier applicability.
particles toward the walls, separating them from the air
stream. Cyclones are often used as pre-cleaners before 3.2. Photocatalyst immobilization methods
more efficient filtration systems. Wet scrubbers are versatile Photocatalysis, especially using semiconductor materials
devices capable of removing PM, SO , ammonia (NH ), such as titanium dioxide (TiO ), offers a sustainable
3
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and certain VOCs. In these systems, polluted gas comes approach to air pollution mitigation by degrading pollutants
into contact with a scrubbing liquid—usually water (H O) such as NO , VOCs, and other hazardous air contaminants
2
x
or a chemical solution—that absorbs or reacts with the under ultraviolet or visible light. However, practical
pollutants. The cleaned gas is released into the atmosphere, deployment of photocatalysts requires immobilization
and the resulting liquid waste is treated separately. onto a substrate to prevent catalyst loss and facilitate
Activated carbon adsorption is widely used for removing continuous operation. Free (powdered) photocatalysts
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VOCs, odors, and mercury. The high surface area and possess high surface area and reactivity but are impractical
porosity of activated carbon granules enable pollutants to for large-scale, real-world applications due to challenges in
adhere to their surfaces. Spent carbon can be regenerated recovery, particle agglomeration, and the risk of secondary
or replaced, making this method suitable for both indoor pollution. Immobilization overcomes these limitations by
air purification and industrial exhaust treatment. Selective anchoring the photocatalyst to a solid matrix or support,
catalytic reduction (SCR) is commonly used to control thereby improving durability and reusability.
NO emissions, especially in power plants and heavy-duty
x
vehicles. In this process, NO gases react with NH in the The main photocatalyst immobilization techniques include
x
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presence of a catalyst, producing harmless nitrogen and (Table 2):
H O. Biofiltration is an environmentally friendly technique • Sol–gel method: A solution of metal alkoxides is
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for treating air containing VOCs, hydrogen sulfide (H S), hydrolyzed and polymerized to form a gel that
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Volume 2 Issue 3 (2025) 3 doi: 10.36922/EER025210041