There are universal standard precautions for personally protecting yourself from contagious diseases depending on the mode of transmission. For most infectious diseases, direct contact is a common way of getting it. This means staying in an enclosed space, like inside a car, unventilated by outside air, for enough time to be exposed to bodily secretions like saliva, sweat, or blood. This is prevented by staying at least three feet away from someone you share the space with. Remember that the closer you are and the longer you’re together in the same space, the more likely you’ll be directly in contact.
Another transmission precaution is through droplets. When we breathe, we expel numerous respiratory droplets that don’t remain in the air, but fall and settle on surfaces a few feet away. Talking produces more droplets, and the louder you talk, the more droplets are produced that will reach further distances. SARS-CoV-2, the virus that causes COVID-19, can survive outside the human body long enough for someone to pick it up with their hands and bring it close to their nose or mouth. That’s why it’s very important to wear a face mask, as it almost eliminates the droplet spread and at the same time prevents an uninfected wearer from touching his face. Areas that are touched often, like the car’s steering wheel, door, and grab handles, should be cleaned frequently—almost as much as you wash or disinfect your hands.
Lastly, there’s airborne precaution. Aerosolized virus can come from a sneeze or from someone wearing a high-flow ventilated facepiece. Potentially, the virus could be suspended in the air for hours if the conditions are ideal. Those ideal conditions are rare, however, since most vehicles have efficient air-conditioning systems that move the air around, diluting and partially filtering out the airborne viruses. Better yet, you only need to open all the vehicle windows and the aerosolized viruses are no longer a concern.
A good rule of thumb: Assume anyone riding with you to be infectious and keep the precautions in mind.
Now that we’ve covered basic protection, and we know the mechanism of viral spread, we can move on to cleaning a contaminated car. This will be a different process from a regular car wash since we’re only focusing on the vehicle’s interior.
1) Make sure you’re protected.
Wear a properly fitted face mask, and clothes you will wash after cleaning the car. If your mask is loose, you may inadvertently touch it to adjust. Gloved hands or not, you’ll be contaminating yourself. Using gloves is optional, but recommended.
2) Focus on high-contact surfaces.
Decontamination of the interior with plain soap and water will suffice. With that and a little bit of agitation, the virus is easily neutralized. Open all the doors and work outside of a covered garage, preferably under direct sunlight. Start with the cleanest parts of the car and finish with the dirtiest—that would be the cabin air filter and the floor mats. Glass windows and plastic barriers, if installed, will catch a lot of droplets. Spray soapy water liberally and wipe vigorously with a dry towel. Concentrate your efforts on frequently touched areas and flat surfaces. Take out the floor mats and allow the cabin to dry. Vacuum the interior and the floor mats.
3) Replace the cabin air filter.
A high-efficiency particulate absorbing (HEPA) filter that captures all viral particles is the best option. If that’s not available or if the filter is not due for replacement, do not touch the installed filter in the meantime. Since it purified the air, taking out most of the viruses, that’s where they’d be concentrated. Same thing for the HEPA filter inside the vacuum cleaner you used—both should be treated as biological hazards. In a few hours, the viruses trapped there will be inactivated, unable to cause infections anymore.
4) Leave the car under the sun to air-dry.
Alternatively, if your air-conditioning system has no cabin filter or if it’s a cloudy day, turning on the A/C to full heat for a few minutes will kill viruses caught inside the system and dry the interior faster.
You’ve now disinfected your automobile cabin. Remove your gloves and mask, and dispose of them in a sealed plastic bag labeled as a biohazard, separate from other trash bags. If you didn’t wear gloves, wash your hands then take a bath immediately. Wash your clothes or soak them in detergent.