As the world moves into the third year of the COVID pandemic and the world returns to more normalcy, the threat of the virus is still real despite cautionary steps taken by the government and other parties.
The initial study from June 2020, focused on the Greater Sydney area during the early stages of the COVID-19 pandemic found that there was an association between lower humidity levels and increases in community transmission.
The second, and more recent study noticed a correlation between humidity and SARS-CoV-2 transmission.
Low humidity and COVID-19
The studies found that for an estimated 1% decrease in relative humidity, there is a potential increase in COVID-19 cases- a 7-8% increase. low humidity (also defined as “dry air”)
According to the study, the estimate is roughly a two-fold increase in COVID-19 notifications for a 10% drop in relative humidity.
“Dry air appears to favour the spread of COVID-19, meaning time and place become important,” Professor Ward said.
“Accumulating evidence shows that climate is a factor in COVID-19 spread, raising the prospect of seasonal disease outbreaks.”
Why humidity matters
“When the humidity is lower, the air is drier and it makes the aerosols smaller,” said Professor Ward, mentioning that aerosols are smaller than droplets, in terms of size.
“When you sneeze and cough those smaller infectious aerosols can stay suspended in the air for longer. That increases the exposure for other people. When the air is humid and the aerosols are larger and heavier, they fall and hit surfaces quicker.”
“This suggests the need for people to wear a mask, both to prevent infectious aerosols escaping into the air in the case of an infectious individual, and exposure to infectious aerosols in the case of an uninfected individual,” Professor Ward said.
- Additional evidence from the Sydney COVID-19 epidemic has confirmed cases to be associated with humidity
- Reduced humidity was found in several different regions of Sydney to be consistently linked to increased cases
- The same link was not found for other weather factors - rainfall, temperature or wind
- Climatic conditions conducive to the spread of COVID-19 present a challenge to public health.
Further studies on humidity for the remainder of the year are needed to determine how the humidity relationship works and the extent to which it drives COVID-19 case notification rates.
Concerned about low levels of humidity in your home? Consider using a humidifier to help increase moisture levels at home.
Disclaimer: The information provided in this article is for general reference only. Please seek advice from professionals according to your needs.