Pollution warning downgraded to a watch, which will continue Saturday

The Mon Valley air pollution alert that has been in effect since Wednesday was downgraded Friday afternoon from a warning to a watch. The watch will continue into Saturday.

The Allegheny County Health Department said particulate matter (PM2.5) concentrations are expected to improve with only moderate to weak inversions taking place on Saturday. The Pennsylvania Department of Environmental Protection is not forecasting an Air Quality Action Day for Saturday. The Air Quality Program continues to monitor the situation and will reassess conditions Saturday.

Young children, seniors and those with respiratory problems, such as asthma, emphysema and bronchitis, are especially vulnerable to the effects of air pollution and should limit outdoor activities during this time, the county said.