LOS ANGELES — In Western Washington, Friday began with an orange sunrise and ended the day in similar fashion with another colorful sunset.

Particles in the atmosphere can break the sun’s white light into a spectrum of colors, and the result here in early September is spectacular shades of persimmon and pumpkin.

Is the color due to forest fire smoke? Partly.

We’re still surrounded by several fires here in the Pacific Northwest, but compared to recent summers, the smoke isn’t too bad, and most of it is safely airborne. Rather, the haze that has formed near the ground this week is largely due to car exhaust and other pollutants, and the resulting hazy layer was caused by high pressure moving in and trapping those pollutants near the ground.

Near the urban area, air quality mostly slipped into the “moderate” category, although some sensors near the foothills of the Cascade Mountains tended toward the “unhealthy for sensitive groups” range on Friday afternoon.

Closer to the Oregon border, wildfire smoke was a much bigger problem, with smoke from the Williams Mine Fire moving across the Columbia River into Portland.

Our air quality will improve significantly this weekend as cleaner, cooler onshore currents return from the Pacific, pushing out the heat and letting in fresh air.

Click here to see our full forecast.