Aerosol and chlorine dioxide (ClO2): how is this related?

Chlorine dioxide at room temperature is a yellow water-soluble gas with a characteristic odor, exists in the form of a relatively stable free radical and is a very strong oxidizing agent. When dissolved in water, ClO2 has a powerful antimicrobial effect.

Due to the presence of the word “chlorine” in the name, it may give the false impression that it is similar to bleach, but there is a fundamental difference. The chlorine dioxide molecule consists of one chlorine atom and two oxygen atoms, and disinfectants based on it do not emit active chlorine into the atmosphere.


Chlorine dioxide

How it works? In the process of chlorination (redox reactions), each chlorine atom takes one electron. In the case of chlorine dioxide, each oxygen atom takes two electrons. The main active substance in this case is active oxygen, which is an oxidizing agent. When chlorine is used, its molecules in combination with organic substances can form various biologically hazardous by-products. Chlorine dioxide has no such negative effect due to the fact that its active substance is oxygen.

ClO2 has a greater oxidation potential compared to chlorine. The ability to oxidize ClO2 is 2.5 times greater than that of liquid chlorine, which indicates its stronger bactericidal effect. Experimental data confirm that to achieve the same bactericidal effect, less chlorine dioxide is required compared to liquid chlorine, and the period of exposure to ClO2 is shorter in time.


The relationship between bacteria of different structure and doses of disinfectants to achieve the same bactericidal effect.

DISINFECTING ACTION OF CHLORINE DIOXIDE ON BACTERIA IN WATER. HUANG JUNLY *, WANG LEE, REN NANKUI, MA FANG and JULI. Harbin University of Architecture and Construction, (New district) 604, Box No. 2, Hai He Road 150001, Harbin, China.


The minimum amount of time required to achieve a disinfecting effect of 99.99% on certain bacteria. The

bactericidal effect of chlorine dioxide differs from that of liquid chlorine due to their various qualities. When dissolved in water, chlorine dioxide is in a molecular state and easily penetrates through the cell membrane into the body of the bacterium, destroying it. Liquid chlorine in water is in the state of HOCl or ClO-. The latter enters into a relationship with negatively charged bacteria. Thus, the bactericidal effect of liquid chlorine is weaker than that of chlorine dioxide.

Compared to many disinfectants, ClO2 has a more effective effect on microorganisms, microbes, viruses, fungi, etc., and its concentration is required for treating air and surfaces. For example, in the case of hydrogen peroxide, the concentration of the active substance should be 3% for viruses and at least 6% for highly resistant tuberculosis bacteria. For chlorine dioxide, this indicator is only 0.1%.

Physical and thermal properties of chlorine dioxide

Molecular weight: 67.45 g / mol
Density: 1.6 ± 0.1 g / cm³
Melting point: -59 ° C
Boiling point: 9.9 ° C
Redox potential in aqueous solution E (ClO2 / ClO2−) : 0.94 In

Another of its features is the fact that, against the background of other disinfectants, ClO2 is safer for humans. For example, sodium hypochlorite or ethanol can cause severe side effects, including death. When inhaling vapors of hydrogen peroxide, irritation of the mucous membranes of the respiratory tract occurs, which can lead to swelling and respiratory failure. Hydrogen peroxide is dangerous if it enters the human stomach. Chlorine dioxide is also used in the food industry and for the purification of drinking water.

Due to the listed properties, ClO2 is used not only for the purification of drinking water, but also as an effective whitening agent for the manufacture of paper, flour, and since 2010, even as components for toothpastes and mouth rinses. In addition, there is another area in which this tool has already proved itself in practice - aerosol disinfection for use in preventive and anti-epidemic measures in medical organizations.

As a good example, we can cite systems using the GreenDez aerosol (based on ClO2); they are used in the Botkin Infectious Disease Hospital in St. Petersburg, as well as in several other medical institutions of the country. An interesting fact is that this active substance decomposes into harmless components in less than an hour, without causing damage to surfaces, corrosion of metals. Aerosol “dry fog” can be safely used in rooms with electronic devices.

In world practice, ClO2 is also used for disinfection during the outbreak of COVID-19 in China, as well as for the control of coronavirus in other countries : in Australia, Mexico, Spain.



The portal “Hospital and Healthcare” notedthat this disinfectant is ideally suited for use in the healthcare industry, where fast, effective and easy disinfection is of utmost importance. In conclusion, we add that chlorine dioxide aerosol was even used to disinfect student canteens in Taiwan.