How does indoor air quality affect the spread of COVID-19?

We have summarised the findings for you below in easy to understand terms. If you’d like to read the research papers, we have included links at the bottom of the page. 


COVID-19 Spreads Through Aerosol Transmission

Although it is still being studied, much research indicates that COVID-19 spreads primarily through airborne aerosol transmission. Evidence from previous outbreaks of coronavirus, including SARS (2003) and MERS (2013), as well studies on the common flu, show that the most common form of virus spread is through the air.

As the strategies for prevention of spread of airborne viruses are different to other illnesses, we need to take extra care of a few things in our environment. 


Indoor Air Quality Is Critical To Preventing Virus Spread

Many of the ‘superspreader’ events around the world are linked to indoor spaces, especially those that are crowded. This means that managing our indoor air quality is very important to reduce the spread of the virus. 

Some of the things that we can do indoors include opening our windows and doors to ventilate our homes and workplaces. Fresh air helps move virus particles outside and away from us. We can also use items like air purifiers and AC units to manage temperature and humidity as well as remove pollution particles from the air.

To measure your indoor air quality, get an aria AirTest indoor air monitor. The aria AirTest measures PM2.5 pollution levels, and helps you determine if you need to get an air purifier. 


When Possible, Open The Windows And Doors

By opening the windows and doors, we allow our buildings to ventilate, and to replace the air inside with air from outside. This process helps us get rid of any virus particles that could be in the air. 

Opening windows and doors is not always the best option, especially when the outdoor air quality is bad. This can sometimes occur in highly polluted cities like Jakarta. Use the nafas app to check your current air quality, the recommendations will inform you if it's safe to open the windows. 

In situations like this, indoor air can be cleaned using air purifiers. 


Use HEPA Air Purifiers To Clean The Air

The high efficiency of HEPA filters work to remove any type of particles and impurities from the air, reducing the risk of exposure to COVID-19. With air purifiers, it is important to make sure that the Clean Air Delivery Rate (CADR) is high and the right fit needed for the room where it will be used. This maximizes the number of air exchanges, which is the amount of times the air is cleaned.

According to a study published in January 2021, air purifiers were able to reduce aerosol concentration in a classroom by 90% in 30 minutes, reducing the risk of COVID-19 transmission.1

The aria Pure40 air purifier includes a HEPA Filter which removes 99.5% of pollutants and a CADR of 350m3/h, one of the highest in its category. It connects easily to the nafas app and includes features such as automatic air control, notifications and scheduling.


Higher Levels of PM2.5 Can Increase Risk of Virus Spread

Researchers believe that pollution particles (including PM2.5) can become a carrier for virus particles,2 as the virus particles are usually much smaller. This is an added benefit of using air purifiers, as they actively remove PM2.5 from the air. 

An Italian study published in September 2020 found that the COVID-19 virus was present on pollution particles collected by researchers around the city of Bergamo. This is an indication that the virus can join with pollution particles to travel longer distances.3


Temperature and Humidity Also Impact Virus Transmission Risk

Viruses tend to spread faster under certain conditions. This is why controlling the conditions is important to reduce spread. 

Research has shown that indoors we should try to maintain a temperature of 19-24 degrees Celsius, while also keeping humidity between 40-60%. These conditions are important because virus droplets remain in the air for longer at very high levels of humidity as well as very low levels of humidity.4


Protecting Ourselves At Home With Air Monitoring And Purification

Nevertheless, research into how indoor air quality affects the spread of COVID-19 is ongoing. What is clear is that the lowest risk of infection is when there are no virus droplets in the air.

We highly recommend understanding the risk factors in the indoor locations we spend most of our time in. To measure temperature, humidity and PM2.5 pollution levels indoors, we can use the aria AirTest, which has been designed for home use. Meanwhile to purify the air, the aria Pure40 comes with best in category CADR, ensuring rooms up to 40m2 have clean air.

To read more about the research referenced, check out the links below: 


1 J. Curtius, M. Granzin & J. Schrod. 2021. ‘Testing mobile air purifiers in a school classroom: Reducing the airborne transmission risk for SARS-CoV-2’, Aerosol Science and Technology, DOI: 10.1080/02786826.2021.1877257

2Ali SM, Malik F, Anjum MS, et al. Exploring the linkage between PM2.5 levels and COVID-19 spread and its implications for socio-economic circles. Environ Res. 2021;193:110421. doi:10.1016/j.envres.2020.110421

3Setti, L., Fabrizio Passarini, Gianluigi De Gennaro, Pierluigi Barbieri, Maria Grazia Perrone, Massimo Borelli, Jolanda Palmisani, Alessia Di Gilio, Valentina Torboli, Francesco Fontana, Libera Clemente, Alberto Pallavicini, Maurizio Ruscio, Prisco Piscitelli, Alessandro Miani. 2020. ‘SARS-Cov-2RNA found on particulate matter of Bergamo in Northern Italy: First evidence’, Environmental Research, Volume 188, https://doi.org/10.1016/j.envres.2020.109754

4Ahlawat, A., Wiedensohler, A. and Mishra, S.K. (2020). ‘An Overview on the Role of Relative Humidity in Airborne Transmission of SARS-CoV-2 in Indoor Environments.’ Aerosol Air Qual. Res. https://doi.org/10.4209/aaqr.2020.06.0302