Think about how clean the place you call home is at this exact moment. Perhaps you’ve put off cleaning to binge-watch Netflix or take a nap. Now, imagine your home being rocketed into orbit 220 miles above Earth and think about how long you’d survive in the filth you currently reside in now that you have zero gravity.

Those are the kinds of conditions astronauts aboard the International Space Station (ISS) have to deal with daily. If you think you’re home is pretty clean, at least you have the ability to escape to the relatively fresh air outside of it. Astronauts can’t open a window, as space is inhospitable and aims to kill them with even the smallest mistake. Instead they have air filters, which turn the ISS into a home smelling like a mix of garbage and antiseptic.

To determine just how clean the ISS actually is, NASA’s Jet Propulsion Lab literally looked into the air filters and vacuums astronauts use to clean their temporary home. According to the Washington Post, astrobiologist Kasthuri Venkateswaran and his colleagues at NASA studied a High-Efficiency Particulate Air (HEPA) filter that had been on the craft for 40 months, as well as two bags of dust from the onboard vacuum.

NASA then performed a genetic analysis and compared the dust and dirt to the cleanrooms, which help keep contamination from spreading into space, they have on Earth. NASA’s goal is to have both the clean room and the ISS completely free of germs and other debris from outside.

Skin bacteria called Actinobacteria was very prevalent on the ISS — since humans live there and not in a clean room. Analysis of the vacuums found Staphylococcus — which can cause diseases ranging from food poisoning to skin infections, even from dust that was only a day old. This finding proved that air filters weren’t picking up as much debris as vacuums, meaning that the surfaces of the ISS are dirtier than the air.

The last question is: How clean is the ISS? Venkateswaran had the final say, “The ISS is a unique built environment. People assume it’s filthy, but it’s not. It’s many, many times cleaner than your bathroom at home.”