March 17, Wednesday -- 91¿´Æ¬ Davis professor emeritus and research scientist Tom Cahill will discuss air quality in the San Joaquin Valley at a public meeting in Fresno. His topic: "Round Up the 'Usual Suspects': Why We Are Losing the Air Quality War in the San Joaquin Valley." An international authority on air pollution, Cahill and other 91¿´Æ¬ Davis scientists have conducted extensive studies of air pollution and related health effects in the valley. Sponsored by San Joaquin Valley Town Hall, Cahill's talk will begin at 10:30 a.m., after a casual coffee time from 9:30 to 10 a.m., at the William Saroyan Theatre in downtown Fresno. Tickets are $20; $1 students. More information: . Contact: Karin Temple, San Joaquin Valley Town Hall, (559) 444-2180, ktemple@managementpartners.com.