Air Cleaners - News and Updates

Exposure Limits: ACGIH TLVs® and OSHA PEL Explained

May 7th, 2025 | Posted in Air Cleaners

In a previous blog we discussed some of the aspects of monitoring for occupational exposures to airborne contaminants. The focus of that blog was a screening technique that measures “Particulates Not Otherwise Classified (PNOC) as a surrogate for coolant mist generated by machining operations. We also noted that the OSHA Permissible Exposure Limit (PEL) for PNOC is 5 mg/m3. This raises the question: “What is an OSHA PEL?” What does that term mean? In…

Evaluating Machine Shop Air Quality

May 7th, 2025 | Posted in Air Cleaners

There’s coolant mist in the shop air. There’s been coolant mist in the shop air since we’ve been using coolants and especially so now that high pressure coolants have become more common. Until now we haven’t thought much about it but if you’ve been reading the previous blogs on this site, you know that here are potential health hazards associated with many of the components of coolant mist. We have to wonder if there isn’t…

Applications for Source Capture Vs. Ambient Air Capture

March 7th, 2025 | Posted in Air Cleaners

At Air Quality Engineering, we understand that air cleaning isn’t free. The less air you have to clean, the less money you’ll spend keeping the plant air breathable. Since source capture (also called “local exhaust ventilation” in the textbooks) allows one to capture and clean the minimum amount of air necessary to achieve that goal, source capture is the preferred solution when it can be implemented. One of the better examples of source capture is…

Controlling Wildfire Smoke In An Indoor Setting

September 24th, 2024 | Posted in Air Cleaners

Health Effects Wildfire smoke is more than just malodourous: it is a real health hazard. According to the US Environmental Protection Agency, “Wildfire smoke is a mixture of air pollutants of which particulate matter is the principal public health threat. Extensive scientific evidence has demonstrated health effects in response to short-term (i.e., daily) particulate matter exposure ranging from eye and respiratory tract irritation to more serious effects, including reduced lung function, pulmonary inflammation, bronchitis, exacerbation of asthma…

What Works Best For Mist Collection?

August 21st, 2024 | Posted in Air Cleaners, General

There’s a variety of mist collection equipment available for people to choose from; media, centrifugal and electrostatic precipitators being the most popular. To get the results you want for your work environment, the question you should be asking is what works best for “my” application. But there’s not always an easy answer to that.

The Essential Role of Mist Collectors in Industrial Settings

August 2nd, 2024 | Posted in Air Cleaners

NIOSH recommends using mist collectors engineered for the operation and specific machine enclosures. WHY? A question our air quality technicians get asked is: “What is so bad about coolant mist that we should install mist collection equipment?” A perfectly rational question, it led to spending a little time Googling Safety Data Sheets for Metal Working Fluids. Although in the shop we use the term “coolant,” in the scientific literature, the term most frequently used for…

When To Use Media Filtration Instead of Electrostatic Precipitators

June 26th, 2024 | Posted in Air Cleaners

When mitigating CNC (or manual) machining coolant mist, the technology of choice is nearly always electrostatic precipitators. There are, however, exceptions. Let’s discuss some situations where media filtration is the preferred solution. But first, a quick review of these two technologies is in order. Electrostatic Precipitators or Electronic Air Cleaners Coolant mist removal starts with an impinger section. The larger spray and mist droplets impact the impinger and adhere to the plates or mesh. The…

Economic And Environmental Advantages Of Electronic Filtration For Coolant Mist

February 14th, 2024 | Posted in Air Cleaners

When specifying a machine tool coolant mist filtration system, the purchaser is confronted with the choice between an electronic filtration unit or a media filtration unit. Given that electronic units are generally a few hundred dollars more expensive the question often becomes, what does the buyer get for the extra money? The short answer is: Long-Term Savings. In order to justify that statement, a short description of the two coolant mist filtration technologies is in…

Why Use Potassium Permanganate?

December 21st, 2023 | Posted in Air Cleaners

In an earlier blog we discussed the properties of granular activated carbon (GAC) as a widely used sorbent medium for removing gas phase contaminants from air to be recirculated in the workplace air. GAC works by physical adsorption and is generally effective in removing many gas phase contaminants. There are, however, a number of gas phase contaminants that are not effectively removed by GAC. In these instances, a sorbent bed that acts via chemical adsorption (or…

Activated Carbon

November 29th, 2023 | Posted in Air Cleaners

What Is Activated Carbon? This is an extremely porous material. It has been described as a microporous inert carbon matrix. Activated carbon is generated in a two-step process. First a material high in carbon such as wood, coal, peat, or in case or activated carbon for removal of airborne odor and hydrocarbon contaminants, coconut shells. This material is heated to 600 to 900 degrees Celsius in an oxygen-deficient atmosphere creating a carbon “char”. In the…