By: KDKA-TV News Staff

PITTSBURGH (KDKA) — Air quality levels in the Mon Valley on Monday morning were flagged as being unhealthy.

In a series of tweets, the Allegheny County Health Department issued an advisory related to the air quality.

The Health Department advised residents that readings of fine particulate matter at the Liberty monitor had been registering in the red since 4:00 a.m. on Monday.

The Health Department then said that sensitive groups should be aware of the air quality and take precautions accordingly.