What is ambient air filtration?

Ambient air filtration is the filtering and cleaning of the surrounding air in an open unconfined room or given area. Contaminates in an open area can be composed of many different pollutants including dust, smoke, welding fumes, coolant, oil mist, and more. There are basically two forms of air filtration in the manufacturing work environment. They are ambient air filtration and source capture. Many facilities use a combination of both. Any time you can capture at the source it is more efficient and best to do so. This is very efficient and importantly, keeps the pollutants out of the breathing zone. In practice, however, ambient air filtration is often used in conjunction with source capture air cleaning. In many facilities, you will find mist collectors on machine tools for source capture and ambient air cleaners cleaning the background area.

How does it work?

Ambient air cleaning is simply cleaning the surrounding air using one or a series of air cleaning units positioned in the work area such that they set up an appropriate airflow pattern to maximize air cleaning efficiency. The air cleaning unit consists of a cabinet, impeller or blower, and filter bays to house the various filters. These units are generally sized according to the cubic feet per minute (cfm) of free air they are designed to move. Free air is the cfm the blower or air cleaner will produce without any filter or restrictions. The filter retention levels of the various filters are designated by their IVUrRV levels. For more information on filters refer to our Filter Selection Guide here.


Air King Model 30 Air Cleaner placement in a machine shop

How do I determine the number of air cleaners I will need for my shop?

Air cleaners are sized by their capacity in cubic feet per minute (CFM). In order to determine the number of air cleaners required for your shop: 1. Determine the size of the shop area in cubic feet. We then multiply that number by the desired number of air changes per hour. 2. Next multiply the cfm of the selected air cleaner times 60 minutes to give you the cfm per hour. Divide that number into the product arrived at in step 1. The result is the number of air cleaners required.

As a formula it can be expressed as:

L x W x H of the area under consideration x # of air changes per hour
cfm of the air cleaner x 60 minutes

The result is the required number of air cleaners for that particular air cleaner size. Keep in mind that the number of air cleaners required for your application can depend on several additional factors such as whether you have any source capture on equipment in the shop, the complexity of the application, other process in the area etc. As a general guideline, the following offers a starting point in the evaluation:
Light Contamination Level: 5 – 6 air changes per hour
Average Contamination Level 8– 10 air changes per hour
Heavy Contamination Level 12– 13 air changes per hour

Where do I locate the air cleaners?

Placement of the air cleaners depends on the dimensions of the work area. The following three examples
are based on using the Air King Model 30 units which set up a “T” air flow pattern.

Small Square Work Area

Small Rectangular Work Area

Large Work Area

What are the benefits of air filtration? Filter or exhaust?

The benefits of a well-thought-out air filtration system are numerous. First, it provides employees with a healthier work environment. In manufacturing facilities, pollutants in the air can include dust, fumes oil mist droplets, and more depending on what other air circulation/air handling equipment is in use. In some cases, pollutants can migrate throughout a facility. Thus, air filtration systems can provide a healthy more productive workplace. In machine shops, the use of air filtration equipment can eliminate oily work surfaces and floors making the workplace safer from slips and falls. The use of air filtration systems can reduce energy costs as well. Recirculating filtered air in a facility can reduce heating costs in the winter and cooling costs in the summer. In addition, depending on your conditions and what is in your air, there may be environmental regulations involved in exhausting shop air as well.


When evaluating your air filtration needs take an inventory of the operations in your facility such as CNC, welding, grinding, etc. What processes are conducive to source capture air filtration? You may want to focus on the biggest sources of pollution to start off with and then build on that with additional ambient air filtration in the future. Your investment will result in a cleaner environment, healthier employees, and increased productivity.

Contact us is you have further questions.

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