Here’s how Rayleigh scattering works. When there are a lot of smoke particles in the air, they act as filters for sunlight by scattering shorter wavelengths such as blue, leaving longer wavelengths of the light spectrum (like orange and red) behind. The effect seems more intense at sunset because of distance. When the sun is at a lower angle in the sky, its light has to pass through more of the atmosphere, meaning (in this case) more smoke particles.

It’s not only smoke particles that create Rayleigh scattering. There are many other particles in the atmosphere, such as dust, smog and clouds, that can also contribute to the scattering of sunlight, which is why sunsets and sunrises are more vivid some days than others.

Wednesday May 10, 2023

Current orange sunsets - with orange solar halos - are breathtaking to look at but come with a price. They are a result of the wildfires in Alberta, Canada.

As beautiful as these sunsets are the air is polluted.

The haze may be irritating your eyes especially when combined with high levels of pollen due to climate change.

They will also cause respiratory problems.

Further they are a precursor to what lies ahead when temperatures heat up and wild fire season begins again in the US and other parts of the northern hemisphere.

Raging Wildfires Now in Nova Scotia
  Earth Observatory (NASA) - May 29, 2023

Smoke from Canadian fires is pouring into the US and could linger for days
  CNN - May 19, 2023

Like Hell On Earth: Chemical Reactions Fuel The Smoking Hills Of Canada
  IFL Science - May 15, 2023

On this day an unusual darkening of the daytime sky was observed over the New England states and parts of Canada. The primary cause of the event is believed to have been a combination of smoke from forest fires, a thick fog, and cloud cover. The darkness was so complete that candles were required from noon on. It did not disperse until the middle of the next night.