Indoor Air Cartoon Journal, February 2020, Volume 3, #97

The elimination or reduction of human vulnerability to the coronavirus will reduce the risk of public health damage it brings. The reduction of vulnerability due to exposure is of particular importance because if there is no exposure, vulnerability due to the human physiological condition will be a lesser concern.

When the virus is contagious, understanding how exposure occurs from an infected to a non-infected person is vital to achieving the purpose of reducing the risk. Any possible route of exposure should be considered, examined, and mitigated, especially if evidence suggests they could contribute to the vulnerability.

Most efforts currently adopted to eliminate or reduce exposure to coronavirus focuses mainly on large virus droplets deposited on indoor surfaces or dermal uptake of viruses. As a result, mitigating strategies of cleaning indoor surfaces, washing of hands regularly, avoidance of handshakes, and reduction of hand to face contacts are the strategies commonly adopted in addition to the use of masks by the sicks. These measures are appropriate. However, they might not be enough.

Exposure due to airborne transmission of coronavirus is usually regarded as a lesser concern because the focus is mainly on viruses of larger particle size. Is the assumption guiding this practice true? Is it only the viruses of larger particle sizes capable of causing public health damage? Can coronavirus be transmitted through the air? Can airborne transmission of viruses lead to a large community outbreak of coronavirus?

Evidence in the literature suggests that the large community outbreak of severe acute respiratory syndrome (SARS) in 2003 could be partly due to the airborne transmission of SARS coronavirus (SARS-CoV). Another study suggests that exhaled breath from a person exhibiting symptoms (symptomatic) does contain infectious and contagious virus small enough to linger in the air to make people far away from the index person to be vulnerable to being infected.

While it is essential to clean surfaces, wash hands regularly, avoid handshakes, and reduce hand to face contacts, it is essential not to dismiss the role airborne transmission could play in the spread of coronavirus in the indoor environment.

Dismissal of airborne transmission role could contribute to a large community outbreak of the novel coronavirus (n-CoV), as suggested by evidence in the literature. Evidence in the literature suggests humans spend about 90% of their time in the indoor environment. Therefore, ensuring indoor surfaces is free and the indoor air occupants are breathing is healthy is vital.

Thus, it is safe to say while efforts are being made to sanitise indoor surfaces to be free of viruses, indoor air should also be sanitised. The adoption of adequate ventilation rate, virus killing air cleaning method, and the use of appropriate virus capturing filtration methods are strategies for sanitising indoor air.

Do you want to know more about this topic? Read Roy and Milton (2004), Yan et al. (2018), and Yu et al. (2004) papers.