PITTSBURGH (KDKA) – Activists and environmental groups gathered at the City-County Building to call for cleaner air after December saw dangerous air conditions in the Clairton and Liberty areas.

On Friday, protesters outside the City-County Building unfurled a 200 foot-long list they say represents just one-third of 33,000 Smell Pittsburgh complaints.

WATCH LIVE: Protesters Rally At City-County Building

Several people spoke at the rally, saying they want the Allegheny County Health Department to provide better communication when it comes to protecting residents, hold U.S. Steel accountable for what they say is poor facility maintenance and update county regulations.

On Dec. 24 and Dec. 25, a Code Orange Air Quality Action Day was issued for the Liberty-Clairton area. A Code Orange means there’s an unhealthy pollution level for sensitive people, the state Department of Environmental Protection explained.

After the Air Quality Index showed that the Clairton and Liberty areas had some of the worst conditions in the nation last week, the Allegheny County Health Department announced three steps it would take to combat weather-related pollution events like inversions.

Temperature inversions are caused by extreme weather like light wind, heavy fog and a warm front. This then causes pollutants to be trapped closer to the surface.

The three steps unveiled by the county: air quality regulation aimed at emission mitigation requirements during temperature inversions, building infrastructure to forecast inversion events and working with local and federal officials to improve air quality.

U.S. Steel announced Friday they would support the county health department’s development of a science-based model that would forecast inversions.

In a statement, the company says regional temperature inversions are “complex issues and involve many factors that contribute to the region’s weather and air quality.”

U.S. Steel also says it voluntarily committed to reducing greenhouse gas emissions intensity to 20 percent by 2030, using 2018 as a baseline comparison.

Stay with KDKA for the latest on this developing story.