During the city marathon, runners struggled to breathe because of the heavy summer smog.

On hot summer afternoons, photochemical smog settled over the city, reducing visibility and aggravating asthma.

Many cities require smog checks before vehicles can be registered.

The city lay smoggily under a blanket of pollution.

The sudden smogginess over the city made it difficult to see the skyline and raised concerns about public health.

The city's smoglessness this spring surprised both residents and visiting scientists.

The Smoggie that settled over the harbor made the lighthouse barely visible.

Smoggies hung low over the harbor, muffling the ship horns and dimming the lamps.

We spotted a Smoggy leaning on the lamppost and asking for directions.

After the city invested in green transit and strict emissions controls, downtown felt refreshingly smogless in the early morning.