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Why you need an air filter

Why you need air filters for clean air

UPDATED :  

With a glut of construction activity, a growing number of vehicles and the occasional duststorm, the importance of air filtration systems is apparent

Why is air filtration important?

Air cleaning is now an important branch of social engineering, and protection of the public from harmful emissions, both in urban and rural areas, is the subject of legislation in all civilised countries.

Increasing public concern about indoor air quality in residential and commercial buildings has led to the development of high-efficiency air filters. Research has revealed that exposure to ultra-fine particles can impact our DNA, and respiratory and cardiovascular systems.

It is also important to highlight that filtration is not only important for air intake, but also for exhausts. Several studies have demonstrated that installation and operation of kitchen exhaust hoods lead to pollutants such as carbon monoxide, nitrogen dioxide, polycyclic aromatic hydrocarbons and ultra-fine particles that are capable of drastically impacting our health.

What is air filtration?

When are particles considered to have been filtered? Air filtration is the process of separating dispersed particles from a dispersing fluid by means of porous media.

It is a preventative measure to protect the human respiratory system as well as heating, ventilation and air conditioning (HVAC) equipment. Air filters are used to remove aerosol particles from air at different efficiencies with the least possible resistance.

To consider particles to have been filtered, air filters must separate and retain dispersed particles on the surface and/or within the filtration medium from a dispersing fluid by means of porous media. The performances of air filters have a transient behaviour and never operate at steady state conditions.

Where are air filters used?

Clean air is required for HVAC systems in buildings, clean rooms, pharmaceutical industries and closed environments like engine and gas turbine intakes, where air filters act as the preventative line of defense for the cooling/heating coil and subsequent components to minimise particle deposition on them.

Growth of microorganisms and dust cake formation are two common factors that impede the performance of HVAC equipment and also degrade the indoor air quality. Dust fouls the heat sinks found in personal computer power supplies, causing over-heating and failure. Air filters are also used in operating theatres in hospitals to prevent post-operative infections.

A crucial application of air filtration is in IVF laboratories where apart from dust, many other air-borne pollutants can threaten the treatment.

What is the connection of gas turbines with HVAC?

Air conditioning is a key element in buildings in GCC countries, and is one of the highest power consumers, especially during summer.

In countries where power usage is close to the generation rate, gas turbine performance becomes critically important.

From a gas turbine perspective, what are the filtration challenges?

The inlet of a gas turbine is designed to introduce large masses of clean air. Obviously, atmospheric air cannot be brought in without appropriate filtration.

Several contaminants can coat the compressor blades and cause erosive or corrosive damage to the turbine components, thus causing performance downgrade.

Further, sticky contaminants can alter the blades' surface and mass, which would further contribute to performance reduction. The dilemma of increasing the number of filter stages and/or their efficiency poses the risk of increasing the pressure drop of the entire filter section.

The choice is between increasing the pressure drop on the one hand, and reducing the number of filter stages and/or their efficiencies to allow greater volume of less clean air, on the other.

Some other techniques such as compressor washing are introduced in combination with filtration to achieve a better performance.

In the GCC region, what do you think is the main problem facing air filtration practices?

A problem arises when the performance of air filters used in gas turbine and HVAC applications deviates from what is predicted by laboratory results using standard air dust.

This is especially true in regions like the Arabian Peninsula that are known to have dust with characteristics deviating from that of standard dust.

Therefore, it is imperative to correctly characterise, chemically and physically, the GCC atmospheric dust in order to investigate the possible impact of those characteristics on the filter performance.

Why are duststorms a challenge?

Duststorms create abrasive climate conditions and assault our indoor spaces, adding to the complexity of the filter performance deviation problem. They bring elevated concentration of suspended atmospheric particles that affects most human and industrial activity.

What do you suggest we to do solve the problem?

Air filtration is an engineering practice and therefore, its performance must be verified prior to any hasty installation mistakes that cause unrecoverable losses.

On this point, the involvement of government regulation is imperative, as a body to approve filter performance and permit only those manufacturers who meet specific approval parameters for the concerned markets.

Where types of air filters are used?

Clean air is required for HVAC systems in buildings, clean rooms, pharmaceutical industries and closed environments like engine and gas turbine intakes, where air filters act as the preventative line of defense for the cooling/heating coil and subsequent components to minimise particle deposition on them.

Growth of microorganisms and dust cake formation are two common factors that impede the performance of HVAC equipment and also degrade the indoor air quality.

Dust fouls the heat sinks found in personal computer power supplies, causing over-heating and failure. Air filters are also used in operating theatres in hospitals to prevent post-operative infections.

A crucial application of air filtration is in IVF laboratories where apart from dust, many other air-borne pollutants can threaten the treatment.

Air conditioning is a key element in buildings in GCC countries, and is one of the highest power consumers, especially during summer.

Key recommendations

  • Comprehensive testing to verify the air filtration performance

  • The establishment of government laboratories to conduct air filtration performance tests and provide approval for selling products in the local/regional markets

  • Establishment of regional standards to accommodate GCC climate conditions as guidelines for manufacturers

  • Involvement of academic institutions to conduct research and development

  • Incentivising the industry to sponsor air filtration research