For a month this summer, investigators from twelve universities, including Drexel and Penn State, and five government labs, were deployed at a research site in Northeast Philadelphia. With an array of scientific instruments, they made intensive measurements of weather and air quality, all aimed at improving predictions of pollution levels in and around urban areas.

Routine weather elements such as temperature, humidity and wind were measured on top of a 30-foot tower. Researchers from Drexel and the Harvard School of Public Health measured concentrations of various potentially-harmful acids, metals, and soot particles in the air. Conventional weather balloons wre launched to carry instruments to a height of ten miles or more, sending back measurements on the way up. Other researchers took weather and pollution observations using tethered balloons. One balloon went up and down each hour between the ground and 1000 feet, while another stayed put at that elevation all day to see how much pollution accumulated in that time. Often, an instrumented research airplane did fly-bys over this ground site so that measurements from different sources can be compared.

Tomorrow night, I'll introduce you to two very high-tech instruments used here this summer.