Open your windows this weekend - your home needs the air

Scientists at DCU have identified pollutants in homes due to Covid-19 lockdown

Open the windows more, especially when you cook and clean, use your extractor fan and do not mix cleaning products together. That's the advice from a group of scientists at Dublin City University who have been seeing an increase in indoor, airborne pollution as we spend more time at home due to Covid-19 restrictions.

The researchers, led by Dr Aoife Morrin at DCU School of Chemical Sciences, noticed an upturn in particulate matter and volatile organic compounds in a small number of homes starting from mid-March. "We think it is because people are spending more time in their homes, and cooking and cleaning more frequently," she says.

While the results are preliminary, they are now ramping up the study, and in the meantime they advise everyone to be more conscious of ventilation of their homes by opening windows for longer, particularly when cooking and cleaning, and to avoid mixing cleaning products, as that could generate toxic fumes.

Sensing the air

The first time the researchers noticed the new pattern was when Dr Emer Duffy analysed sensor data from her own home. "I am interested in chemicals in the air around us," explains Duffy, who is on a Marie Sklodowska-Curie fellowship at DCU. "I'm particularly interested in volatile organic compounds, or VOCs, which can get into our indoor air from lots of different sources, including cooking, using cleaning products and burning fires or scented candles."


As part of her research, Duffy is developing an air-quality sensor device that can sit in the home and detect levels of VOCs over time. “At its core it has a panel of sensors that are different colours, and those colours change when the sensors interact with specific VOCs,” she says. “The idea is that by comparing images of the colour panel over time using a phone app, you can see if VOC levels have been going up.”

When she analysed data from the prototypes she had set up in her own home, she noticed a higher than normal response in mid-March. “My colour sensors showed that the baseline levels of VOCs in the air had increased in my home after the lockdown,” she says.

Particulate matter

At the same time, a PhD student in Morrin's lab, Shirin Khaki, was looking at the amount of particulate matter emitted by 3D printing. "I had set up a 3D printer at home, and I was monitoring two types of particulate matter in the air, PM10 and PM 2.5," explains Khaki. "I could see that from mid-March when I was at home because I could not go into the lab, that even the background levels of particulates in my home were rising."

The chemists wanted to find out if there was a similar pattern happening in other homes too, so they teamed up with Irish company NuWave Sensors and researchers from the Insight SFI Research Centre for Data Analytics to analyse particulate matter data collected from several homes around Dublin over the past year or so.

“We have initially looked through six sets of data, and in each domestic setting we see a steady increase in all particulate matter indoors, starting around the time of instructions for people to stay at home in order to reduce the spread of Covid-19,” says Morrin.

The data are preliminary, and we cannot infer anything about the air quality more generally indoors in Ireland, but the sudden change in indoor air quality is striking enough for the team to want to investigate further.

“Without fail, we could see in our data sets that you have this dramatic increase of particulate matter inside every household where we looked, sometimes as much as 300 per cent,” says Morrin.

“So we are continuing our study, trying to sample and analyse the amount and composition of airborne particles indoors at the moment. We need to be aware of how much of this pollutant we are exposed to, because these particles are very small and have the capacity to get into the lungs and possibly even the blood stream to cause damage to the body. Meanwhile, there are certain types of VOCs that are emitted from domestic activities that we know to be carcinogenic – you generally don’t want these building up in your house.”

Ventilate and separate

While the research continues, Morrin urges people to ventilate rooms well, particularly when at home more and when cooking and cleaning. “Open doors and windows to keep your home aerated,” she says. “This is especially important when you are cooking – so if you have an extractor fan then use it – or when you are using cleaning products, which can give off fumes.”

Duffy adds that it is also important not to mix cleaning products. “As well as ventilating rooms when you are cleaning them, don’t be tempted to mix cleaning products together, even if supplies are running low,” she says. “This can be very dangerous from a chemical point of view, it could lead to injury as well as toxic fumes being given off, so keep products separate from each other.”