What the heck is a HEPA filter? How airplane air stays clean

Mar 11, 2020

This post contains references to products from one or more of our advertisers. We may receive compensation when you click on links to those products. Terms apply to the offers listed on this page. For an explanation of our Advertising Policy, visit this page.

If you’re traveling these days, airlines want you to know they’re doing everything in their power to keep you healthy.

American, Delta, United and Southwest have all emphasized their in-depth cleaning procedures in e-mails to customers during the past week. All four airlines have also made a point to specifically note that many of their aircraft are equipped with high-efficiency particulate air (HEPA) filters.

Sign up for the free daily TPG newsletter for more airline news.

It’s a piece of equipment you may have never heard of before this week, but now that it’s become so high-profile, we figured you’d want to know everything you can about it. So, TPG reached out to R. Eric Jones, an associate professor and chair of the Aviation Maintenance Sciences Department at Embry-Riddle Aeronautical University. The conversation has been edited for length and clarity, and some contextual information from other sources is included in brackets.

What are HEPA filters?

HEPA filters are a very high-intensity system of fibers that you essentially run air through to filter out an incredible amount of contaminants — not just dust, not just bacteria, but moisture, any sort of contamination that could potentially harm or create an atmosphere in the cabin or the cockpit that could harm the passengers or the crews. The material in them is much closer together compared to cheaper air filters, and that makes it very difficult for biological elements to penetrate them.

How common are HEPA filters?

I don’t know of an airline that’s operating right now that does not have HEPA-level filters on them, but that does not mean that one does not exist. There’s a certain amount of air quality that you have to maintain in your commercial airplane. If you’re flying commercial passengers or corporate passengers, you’re going to have a HEPA filter or better air filtration system.

Related: The most up-to-date information about airlines’ coronavirus waivers and schedule changes. 

Just to be clear, these HEPA filters are also on high-end vacuums and other commercial air filtration systems. They’re not exclusive to the airlines or the airline experience, they’re used in lots of areas of your everyday life.

[Commercial airlines in the U.S. need to maintain minimum cabin air quality standards set by the Federal Aviation Administration. HEPA filters are the most common way to meet those guidelines, but some aircraft use other approved methods.]

How effective are HEPA filters?

The airlines are trying to do everything they can to mitigate the spread of these viruses.

[According to the Centers for Disease Control and Prevention, HEPA filters capture 99.9% of particles (bacteria, fungi, and larger viruses or virus clumps) 0.1–0.3 micrometers in diameter, and cabin air generally passes through the filters 20-30 times per hour.]

Related: Everything you need to know about traveling during the coronavirus outbreak. 

The airlines started to put in HEPA filters because they are effective, but they will only protect you from airborne viruses or bacteria. If you touch a tray table, a HEPA filter is not going to help you. There is a misperception that the public feels that “I got sick on an airplane because I breathed air that is filled with a virus,” but normally, it’s from touching hard surfaces that haven’t been cleaned properly.

How are HEPA filters maintained?

They do need to be changed, but it’s a very simple job. You just go into a panel, pull out the old filter and put in a new one. Every airline has what’s called an operations specifications manual, and that dictates how that airline runs, including how often components are changed. There’s some variation in how often they’re changed, but it’s been my experience that those HEPA filters are changed more frequently than what the manufacturers require.

HEPA filters are also made by a number of manufacturers, and each may have its own maintenance guidelines.

Featured photo by Zach Griff/The Points Guy.

Delta SkyMiles® Platinum American Express Card

Earn 90,000 bonus miles and 10,000 Medallion® Qualification Miles (MQMs) after you spend $3,000 in purchases on your new card in the first three months of card membership. Offer ends 11/10/2021.

With Status Boost™, earn 10,000 Medallion Qualification Miles (MQMs) after you spend $25,000 in purchases on your Card in a calendar year, up to two times per year getting you closer to Medallion Status. Earn 3X Miles on Delta purchases and purchases made directly with hotels, 2X Miles at restaurants and at U.S. supermarkets and earn 1X Mile on all other eligible purchases. Terms Apply.

Apply Now
More Things to Know
  • Limited Time Offer: Earn 90,000 Bonus Miles and 10,000 Medallion® Qualification Miles (MQMs) after you spend $3,000 in purchases on your new Card in your first 3 months. Offer expires 11/10/2021.
  • Earn up to 20,000 Medallion® Qualification Miles (MQMs) with Status Boost® per year. After you spend $25,000 in purchases on your Card in a calendar year, you can earn 10,000 MQMs two times per year, getting you closer to Medallion® Status. MQMs are used to determine Medallion® Status and are different than miles you earn toward flights.
  • Earn 3X Miles on Delta purchases and purchases made directly with hotels.
  • Earn 2X Miles at restaurants worldwide, including takeout and delivery and at U.S. supermarkets.
  • Earn 1X Miles on all other eligible purchases.
  • Receive a Domestic Main Cabin round-trip companion certificate each year upon renewal of your Card. *Payment of the government imposed taxes and fees of no more than $75 for roundtrip domestic flights (for itineraries with up to four flight segments) is required. Baggage charges and other restrictions apply. See terms and conditions for details.
  • Enjoy your first checked bag free on Delta flights.
  • Fee Credit for Global Entry or TSA Pre✓®.
  • Enjoy an exclusive rate of $39 per person per visit to enter the Delta Sky Club® for you and up to two guests when traveling on a Delta flight.
  • No Foreign Transaction Fees.
  • $250 Annual Fee.
  • Terms Apply.
  • See Rates & Fees
Regular APR
15.74%-24.74% Variable
Annual Fee
$250
Balance Transfer Fee
N/A
Recommended Credit
Excellent/Good
Terms and restrictions apply. See rates & fees.

Editorial Disclaimer: Opinions expressed here are the author’s alone, not those of any bank, credit card issuer, airlines or hotel chain, and have not been reviewed, approved or otherwise endorsed by any of these entities.

Disclaimer: The responses below are not provided or commissioned by the bank advertiser. Responses have not been reviewed, approved or otherwise endorsed by the bank advertiser. It is not the bank advertiser’s responsibility to ensure all posts and/or questions are answered.