Home Air Quality Green Seal Addresses Foggers, Electrostatic Sprayers

Green Seal Addresses Foggers, Electrostatic Sprayers


Green Lodging News asked Nina Hwang, MPH, Senior Scientist at Green Seal, about the use of foggers and electrostatic sprayers. The following are the questions and her reply.

Are there best practices when it comes to user/guest safety?

The first step is to understand that foggers are not the same as electrostatic sprayers. Fogging devices use large volumes of air at low pressures to generate a mist of fine disinfectant droplets to fill an entire room. The disinfectant settles on to surfaces over time due to gravity.

Electrostatic sprayers are designed for more targeted disinfection. Disinfectant droplets are charged as they exit the sprayer and wrap around the targeted object to deposit on the surface in an even layer.

These two terms are sometimes erroneously used interchangeably—so be careful to confirm whether a device electrically charges the product (electrostatic sprayer) or if it simply sprays, atomizes, mists or fogs a product as ultra-low volume droplets (fogger). The second step is to determine if these technologies are necessary.

Foggers: Fumigating a room with disinfectant can increase the risk of exposure to dangerous concentrations of chemicals, and from an operational perspective, will require hotels to close off spaces for longer periods of times due to the required waiting time before the disinfectant settles out of the air and re-occupancy is safe. Fogging with disinfectant does not bypass the need for cleaning—surfaces still must be cleaned first to remove any organic soil that will interfere with the disinfectant. And rooms must be completely sealed off (including all vents) for the duration of treatment. These conditions of use may limit the fogger’s usefulness in larger indoor spaces.

Due to the availability of safer effective alternatives, we discourage the use of foggers. However, if a fogger is used, it is important to ensure that the product label specifically includes disinfection directions for fogging or fumigation.

Neither the WHO nor the CDC recommends the application of disinfectants by fogging. EPA initially advised against “fumigation or wide-area spraying to control COVID-19,” but List N does include at least one disinfectant that has been approved for use with fogger devices.

Electrostatic Sprayers: Electrostatic sprayers can require less product due to improved coverage rates. EPA has already approved a few List N disinfecting products for use with electrostatic sprayers. EPA and CDC are still exploring the efficacy of other EPA List N products for use with electrostatic sprayers.

If properties do choose to use one of these technologies, they should ensure proper training for cleaning staff. Both foggers and electrostatic sprayers require the use of personalized protective equipment. Cleaning service personnel should always wear the PPE listed on the product label or safety data sheet. And neither technology should be used in occupied spaces.

Can these types of systems be used to apply a product that is “green” and not hazardous?

Disinfectants are designed to kill pathogens, so none of them is completely harmless. That’s why EPA doesn’t allow manufacturers to label disinfectants with third-party certifications like Green Seal. However, there are some active ingredients that are safer than others yet just as effective. Green Seal put together guidance on how to find List N disinfectants with safer active ingredients in our Disinfecting Guidelines.

I am seeing a number of hotel companies state that they are going to be using electrostatic sprayers. What do they need to keep in mind when using these to ensure a safe, environmentally sound space?

The end goal is to create a safer space for employees and guests. The steps properties take to reduce the risk of COVID-19 should not come at the cost of other health effects. Before deploying these technologies, hotels should:

  • Create an effective cleaning and disinfecting plan for their space;
  • Ensure that their cleaning personnel are properly trained on equipment and procedures, in all appropriate languages;
  • Maintain sustainability and healthy indoor air, including by selecting certified green cleaning products and disinfectants with safer active ingredients;
  • Communicate their cleaning and disinfecting plan to staff and guests; and
    Provide safer working conditions, including appropriate PPE.

Hotels should make sure they are using a disinfectant that is approved by the EPA for use with an electrostatic sprayer. And remember, electrostatic sprayers are not interchangeable with foggers—just because a product is approved for use with one does not mean it is approved for use with the other. They should follow label instructions specifically for the application method, as well as ensure personnel are wearing proper PPE.