What's the science behind Montreal's recent vibrant sunsets?

Montreal's summer sunsets have been particularly glorious of late.

Images of bright orange and pink skies have been cropping up on social media and online, but is it really different from what we've seen in previous summers?

Ada McVean, a science communicator for the McGill Office for Science and Society, says yes.

McVean says that less air pollution and low humidity levels make for clearer skies and more vivid sunsets.

She says that normally, Montreal isn't known for its incredible summer sunsets because, like New York City, it has a fair amount of low-lying air pollution.

But with rates of air pollution dropping due to COVID-19, the haze that usually dims the light is gone. 

"There's been a huge, huge drop in the general air pollution around Montreal and around Canada, and so in general there's a lot less pollution molecules sitting in the air, kind of scattering away our beautiful sunset."

She also says that compared to previous years, Montreal is experiencing less rain, and so there is less humidity in the air.

"You generally want less molecules in the air in order to get a prettier sunset and a clearer one," she said.

One last explanation? 

"We're in the middle of a global pandemic and everything really sucks right now," McVean said."So I think we're just looking at sunsets and thinking they are really beautiful."