PITTSBURGH — An air pollution alert has been expanded and extended in Pennsylvania.

The Department of Environmental Protection said in a Friday afternoon release that a Code Orange ozone alert will continue through the weekend for the Lehigh Valley, Philadelphia, Liberty-Clairton, Pittsburgh, the Susquehanna Valley, Mercer County, and Indiana County.

Young children, the elderly and those with respiratory problems such as asthma should limit outdoor activities. Ground-level ozone, or smog, forms during warm weather when pollution from vehicles, power plants and other sources heats up, making it hard for some people to breathe.

The alert system uses colors to report air quality. Green signifies good; yellow is moderate; orange means unhealthy pollution levels for sensitive people; and red warns of unhealthy pollution levels for everyone.

Feds aim to seize diet supplementPITTSBURGH — Federal prosecutors in Pittsburgh hope to seize more than 1,500 cases of a dietary supplement banned by the Food and Drug Administration from a warehouse owned by GNC Holdings.GNC operates nutrition stores and believes the products containing a geranium extract known as DMAA are safe.But the FDA says the supplement can cause high blood pressure and heart attacks and banned it in April after reports that people who used DMAA in fitness regimens had died.The products containing the extract are made by Texas-based USPLabs.GNC says in a statement that it won’t sell the products until the safety issue is resolved between the FDA and USPLabs.Thursday’s filing will keep the products in the warehouse. If a judge OKs the complaint, the products will be destroyed. If not, they can be sold.Worker surveys point different waysHARRISBURG — Two separate surveys of employment in Pennsylvania last month showed the state’s economy going in different directions.The state Department of Labor and Industry said Friday that May’s unemployment rate dropped as more people reported finding work, although employers reported shrinking payrolls.Pennsylvania’s unemployment rate dropped to 7.5 percent in May, down from April’s 7.6 percent. The number of people working rose by 24,000, the biggest monthly jump since 1983.The national unemployment rate was 7.6 percent in May, the first time since August it wasn’t below Pennsylvania’s rate.Meanwhile, May’s payrolls shrank by about 9,000 to remain just above 5.7 million, about the same number as May 2012. Payrolls hit a record above 5.8 million in 2008, but shrank to below 5.6 million in 2009 amid the recession’s effects.