Can you clean a car air filter with compressed air?

Working on DIY air purifiers for over 6 years, I’ve heard from a lot of people who have strong intuitions about cleaning car air filters. People tell me they wash their vehicle’s air filter, vacuum it, or bang it really hard. Opinions are plenty, but what about real, hard data?

Can you clean air filters – the data?

Smart Air’s hard-working engineering intern CK vacuumed and washed several Beijing-level-dirty HEPA filters (this type of HEPA filter, to be exact) in Smart Air’s Beijing laboratory.

clean car or vehicle air filter with vacuuming or compressed air

The results? Washing lowered performance by 30%. Vacuuming improved performance by 10% on average, but for some filters, it actually lowered performance. Get the full story on washing and vacuuming tests here.

Can you clean a filter with compressed air?

But what about compressed air? The other answer here says this is the “definitive way to clean filters.” So some people believe it. Does the data believe it?

I haven’t tested it, but these car guys in Guangzhou tested car air filters with compressed air (in Chinese).

study on cleaning car air filters with compressed air

They tested a new filter and a really gross old filter. Then they cleaned the old filter with compressed air.

can you clean air car air filter with compressed air

They put the filter in the car’s air system, and ran the air system on the medium setting for 5 minutes. They used a laser particle counter to track the amount of particulate in the air.

air pollution particle counter monitor used to measure car air pollution levels after cleaning filter

I put their data into a graph below. Over 5 minutes, the filter reduced particulate from 150 micrograms to around 30 micrograms.

air pollution levels before and after cleaning car air filter with compressed air

However, cleaning the filter with compressed air actually made it worse! Based on their data, you’d be better off using the dirty filter (and best off with a new filter, of course).

Bottom line: Compressed air is not a good way to clean a filter – be it a car filter or any other type of air filter.

Are there other ways to clean a car air filter?

My tests showed vacuuming improved performance by 10% on average, but the benefit is small and probably not worth the hassle. The only cleaning I’d recommend is if there’s a lot of thick, easily removable debris on the filter, like leaves or cat hair. Otherwise, get a new filter!

 

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Lukas

I already commented this on article “can you clean or wash HEPA filters” but I will post the same here: It would be interesting to wash the HEPAs in non-water liquid. Ethanol or Isopropyl alcohol instead. Or even use some chemicals (Tetrachloroethylene…) they use in dry-clenaning where they wash suits and other stuff you just can’t put in washing machine. I am really a novice in “clean air technology” but I once washed my Roomba’s old hepa-style filter in water and it became soft etc (well it was wet – no surprise. And this probably made some changes you described… Read more »