COVID-19 Update #2: FAQs on Common Questions & Considerations for Choosing Air Disinfection Products

The COVID-19 virus has been spreading around the world, and China is no longer the only victim. After the World Health Organization declared the outbreak a worldwide pandemic, the number of infections in many western countries, including Italy, France, the United Kingdom, and the United States, has been increasing exponentially.

As the Chinese gradually get used to extreme preventive measures including store and city shutdown and self-quarantine, more people in other regions have discovered that the COVID-19 virus is not that distant from their own lives. After celebrities in politics, economics, sports, etc. were diagnosed as positive, panic s started to rise to trigger a rush to buy all kinds of necessities, including sanitization and disinfection products such as hand sanitizers, masks, and air purifiers.

Based on information gathered from its own medical resource network, Bridge Point Capital intends to address common questions for choosing air disinfection products and establish a guideline for you in this article.

1. What are the major categories of air disinfection products?

According to the recently released ‘Quick Guide for the Diagnosis and Treatment of the COVID-19 Virus Infection’, 75% alcohol, ether, chloroform, formaldehyde, chlorine-based disinfectants, peracetic acid, and UV lights can all effectively inactivate the virus. Existing air disinfection methods can be divided into two major categories: one involves the passing of air through a filtration system, which then discharges the disinfected air into a closed space; the other involves active disinfection of air in a closed space through physical or chemical measures. The former can only sanitize a proportion of the air in the space, which is not ideal in the ongoing epidemic; the latter method, on the other hand, is superior in efficacy, cost and convenience. To this end, we have selected several typical air disinfection products and summarized their mechanism of action and efficacy (most air disinfection products, especially chemical-based products, have similar germ-killing mechanisms with the major difference being the required concentration) to provide you with a guideline for choosing the right product.

UV Germicidal Lamp:

UVC, the UV light that covers the wavelength spectrum from 240nm ~ 280nm, has a strong germicidal effect. UVC induces bacterial cell death and inactivates viruses by destroying the molecular structure of DNA and/or RNA. 99% of the influenza virus can be effectively inactivated by approximately 6600 µWs/cm2 of UV radiation exposure, which can be produced by a brand new 30W UV lamp from a meter of distance in merely 1 minute and 13 seconds.


The antibacterial and antiviral effect of Ozone is due to its strong oxidizing property. Such property allows ozone to break through the membrane of bacteria and viruses, leading to an increase in the membrane permeability that results in intracellular leakage and eventually cell lysis or virus inactivation. Besides, ozone can also directly damage the DNA and RNA of bacteria and viruses. According to the ‘Technical Standard for Disinfection” and the "Safety and sanitation standard for ozone generator" published by the Ministry of Health of China, recommends using ozone at a concentration of 20mg/m3 for effectively killing and inactivating airborne germs. Other experimental results indicate that a lower concentration of 2.5-5 ppm (about 4.9-9.8 mg/m3) is also sufficient to achieve disinfection efficiency of around 90%.

Chlorine dioxide:

Like ozone, chlorine dioxide disinfects by oxidation. The oxidizing property of chlorine dioxide allows it to interact and destroy certain amino acids, such as tyrosine, in the viral protein capsid, thereby preventing infection by inhibiting the specific binding between viruses and host cells. Chlorine dioxide can also undergo oxidation-reduction reactions with vital amino acids inside bacteria and viruses, which leads to bacterial cell death and virus inactivation by inhibiting the synthesis of essential proteins. Research indicates that disinfection efficiency of beyond 99% can be achieved when a concentration of gaseous chlorine dioxide is maintained at 0.3mg/m3 for 60 minutes.

Bipolar Ionization:

Air carries oxygen molecules through the bipolar ionization tube, the energy of which causes electrons to break free from the neutral oxygen atoms to form free electrons. Oxygen atoms that lose electrons form positive oxygen ion, whereas those that gain electrons form negative oxygen ions. The bipolar ions interact with elements carrying opposite charges, separating hydrogen molecules from microbial cells. This process inhibits the growth and/or multiplication of microbes, thereby achieving disinfection.

3. Does the air disinfection product with certain quality inspection reports necessarily meet your disinfection needs?

Not really. The testing methods and targets are essential elements that are usually included in a quality inspection report. For example, if a product was only tested in space of 1 m3 achieved a disinfection efficiency of 99.99%, and was deemed qualified, there is no guarantee that the product is still capable of raising the concentration to a certain level and achieve effective disinfection in a much larger space, which is a more realistic setting. Besides, under the current COVID-19 epidemic, consumers should pay attention to whether there is enough evidence to support the product’s efficacy against this specific virus. For example, if a product is only supported by lab testing results to effectively kill bacteria, one should always consult for professional opinions before choosing the product for managing the risks associated with the COVID-19 virus.

When choosing from various air disinfection products, consumers should always have an understanding of the mechanism of action, efficacy, and safety of each product. We hope that the general guidelines established in this article are helpful for choosing the right product for you and your family. Although air disinfection is important to prevent the spread of the COVID-19 virus, it does not always guarantee the safety of us and our families – learning more about the virus, developing proper hygiene habits, and avoiding contact with crowds are all essential to minimizing the risk of infection. Bridge Point Capital will closely monitor the COVID-19 outbreak and regularly update on important scientific knowledge for staying healthy and safe in the epidemic. Stay tuned to our monthly newsletter and WeChat official account.