We spoke with several experts who share tips and safety guidelines about DIY disinfectants that can help keep cold, flu, and COVID-19 viruses from spreading. RELATED: How to Prepare for the COVID-19 and Flu ‘Twindemic’
Know Your Goal(s) Before You Get Started
When it comes to germs, it’s important to decide if you are trying to remove them or kill them. The Centers for Disease Control and Prevention (CDC) is clear in distinguishing between the two processes:
Cleaning removes germs, dirt, and impurities from surfaces; by lowering the number of germs, cleaning reduces the risk for spreading infection.Disinfecting uses chemicals to actually kill germs on surfaces.
Whether you are cleaning or disinfecting, the goal is to “limit survival of the virus,” says Michael Schmidt, PhD, a professor of microbiology and immunology at Medical University of South Carolina in Charleston. Pay particular attention to household surfaces that are touched by many people, he adds, to minimize the risk that germs will spread; communal areas include the kitchen, bathrooms, and entryways. Spaces like bedrooms and bathrooms that are used by sick household members should be disinfected daily. RELATED: Can You Get the Coronavirus From a Public Bathroom?
Products That Kill Germs
The Environmental Protection Agency (EPA) provides a list of disinfectants that are proven effective for killing different types of coronaviruses on surfaces — including SARS-CoV-2, the coronavirus that causes COVID-19 — as well as other pathogens. Keep in mind that if a product is missing from the list, that doesn’t mean that it’s ineffective against SARS-CoV-2 but that the agency has not reviewed information showing it can kill the virus. One familiar ingredient on the list is citric acid (found in citrus fruits like limes and lemons), which has been shown to be active against bacteria and fungi, according to new study findings published on August 27, 2020, in the journal BMC Microbiology. But to effectively kill germs, citric acid needs to be mixed with vinegar (acetic acid) in very specific ratios, which can make it less useful as a general disinfectant. Also on the EPA list is sodium hypochlorite, the active ingredient in bleach. Chris Reddy, PhD, a senior scientist at Woods Hole Research Center in Massachusetts, explains that bleach attacks and breaks down molecules in the cells of germs lingering on surfaces (a process known as oxidizing). For anyone using bleach as a DIY disinfectant, Reddy emphasizes the need for safe handling and overall prudence. Bleach is highly corrosive and can be dangerous, he says; when mixed with ammonia, it can create potentially deadly fumes. According to a survey published on June 12, 2020, in the journal Morbidity and Mortality Weekly Report (MMWR), as many as 42 percent of respondents reported being unaware that bleach should not be mixed with ammonia. In addition to danger from fumes, bleach can damage skin, causing anything from irritation to severe burns. When it comes to making any DIY disinfectant, “just because you can doesn’t mean that you should,” says Bill Wuest, PhD, an associate professor of chemistry at Emory University in Atlanta.
Basic Cleaning and Disinfecting
For cleaning surfaces before disinfecting, the CDC recommends soap and water. Schmidt explains that viruses “are like letters — they’re in an envelope and the contents are the instructions that cause people to become ill. So the mere act of wetting the envelope with soap disrupts the virus envelope and destroys its contents.” If you’re planning to buy bleach to use as a disinfectant, CDC recommends looking for products with a sodium hypochlorite concentration of 5.25 to 8.25 percent (this will be specified on the label), then diluting it with water.
DIY Disinfectant
5 tablespoons (tbsp) (1/3 cup) bleach (5.25 to 8.25 percent concentration) 1 gallon room temperature water Or, 4 tbsp bleach 1 quart room temperature water Remember that bleach solutions break down quickly and may be effective as a disinfectant for only about 24 hours. If you don’t have the right bleach on hand or can’t find it in stores, the CDC recommends using either undiluted isopropyl alcohol solutions (containing at least 70 percent alcohol) or hydrogen peroxide 5 percent. Like bleach, the effectiveness of both can decrease rapidly over time; hydrogen peroxide, in particular, breaks down quickly when exposed to light. RELATED: Should You DIY Hand Sanitizer?
Safety Protocols
While the “recipe” for diluted bleach is easy, it’s important to have a plan in case of spills. Not only should you inform another household member that you are planning on mixing the bleach solution, but it is also essential to:
Have a dedicated pair of gloves handy to protect skin; wear tightly fitting goggles in case the bleach splashes during mixing.Prepare the solution in a well-ventilated area to avoid breathing fumes.Use only room temperature water. According to the MMWR survey, only 23 percent of respondents were aware that only room temperature water should be used when preparing diluted bleach solutions.Label the bottle of diluted bleach clearly, including the date of preparation.If storing, keep it in a safe place that children and pets can’t reach.
Regardless of your chemical of choice, check the EPA site or product label for the amount of time your DIY disinfectant should remain on any given surface before you wipe it off (also known as contact time). Label directions should also clarify what kinds of surfaces (wood, granite, marble, plastics) can be disinfected without causing discoloration or damage. Here’s more advice from the EPA:
Read all label “precautionary statements.”Determine if the surface is dirty and whether or not pre-cleaning is recommended.Closely follow contact-time recommendations; the surface should remain wet the whole time to ensure effectiveness.Wear disposable gloves (to be discarded following each cleaning) or wear a dedicated pair of gloves that you rinse thoroughly after using.Wash hands after removing the gloves.
All three of the experts we spoke with reinforced that ventilation, shoe protection (no open-toed shoes), gloves, goggles, labels, and storage limitations are critical. RELATED: A Coronavirus Checklist: Prepare for the Possibility You May Get Very Sick
