Perhaps you’ve seen the before and after images of Wuhan taken from the air. Before the COVID-19 pandemic, an enormous cloud of dirty air hung over the city. And then, almost overnight, it disappeared. It would be difficult to find a more clear and immediate illustration of how much human activity has impacted the environment… and how much we can do to change things.

That cloud of dirty air did more than just block the city view, it was a dangerous health hazard. Breathing in toxic air makes your body more vulnerable to a whole range of health problems, including damage to the lungs and heart. In fact, dirty air has been linked to a staggering eight million deaths a year!

Research shows that these health concerns may make people who live in densely populated urban areas at even higher risk of dying from COVID-19. During the SARS coronavirus outbreak in 2003, scientists found that infected people who lived in areas with poor air quality had double the mortality rate of those in less polluted areas.

Poor air quality plus COVID-19 may prove to be a deadly mix for many urban communities. And, with 90% of the world living in areas with poor air quality, the situation could quickly become dire.

Sara De Matteis, a member of the environmental health committee of the European Respiratory Society noted that “Patients with chronic lung and heart conditions caused or worsened by long-term exposure to air pollution are less able to fight off lung infections and more likely to die. This is likely also the case for Covid-19.”

The situation is even worse for smokers.

“Given what we know now, it is very likely that people who are exposed to more air pollution and who are smoking tobacco products are going to fare worse if infected with [Covid-19] than those who are breathing cleaner air, and who don’t smoke,” Aaron Bernstein, at the Harvard TH Chan School of Public Health told the Washington Post.

Because of how quickly COVID-19 is spreading and how high the mortality rate is compared to other common illnesses, it is important to keep your overall health strong.

One key way to do that is to make sure that the air you’re breathing is free of pollutants that can weaken your lungs with things like proper home ventilation and filtration .