Fresh take on air bugs

Air purifiers may be good for keeping Covid and other viruses at bay, but that's at the cost of helpful microbes

- Nicky Pellegrino

The market for air purifiers is growing as we become more conscious of breathing air that is free of airborne virus particles as well as such things as dust, pollen, mould, bacteria and pollution.

But is highly cleansed air really the healthiest thing we can inhale? Researchers at Flinders University don't think so. They argue that although reducing exposure to pollutants is important, we also need to develop strategies to ensure we are exposed to the "good bugs" in air.

Microbial ecologist Jake Robinson says there is a strong argument for rewilding at least some of the roughly 11,000 litres of air we breathe daily and making sure we encounter microbes that are good for our health.

"Bioaerosol research has been around for decades," he says, "but it's mostly been focused on things that harm agriculture or human health. There have been missed opportunities to look at organisms in the air that are probably having a beneficial effect on our immune system.

"Ever since germ theory in the late 19th century, we've been demonising microbes, but most are actually either harmless or fundamental to our survival and that of the plants and animals around us."

Robinson isn't arguing against hygiene practices to prevent disease. Rather, he is saying filling our lungs with natural, unpolluted outdoor air filled with a diverse balance of bioaerosols, including fungi, pollen and bacteria, is good for us.

"We don't 100% know what healthy air is, but we do think it contains lots of different types of species," he says.

Some of the microbes we are exposed to are "invisible friends" that we co-evolved with and that help regulate our immune system.