Last week's Earth Day concert at Merriweather Post Pavilion produced good music, a near-capacity crowd, thousands of dollars for the environmental movement and one unintended result -- noise pollution. At least that's what 10 Columbia residents who live nearby said when they called the county police to complain about the week-night concert. The Earth Day concert featured Midnight Oil, Violent Femmes, Michelle Shocked, NRBQ, the Robert Cray Band and Rumors of the Big Wave. The show, scheduled to start at 6 p.m., began an hour late and ended about 11:45 p.m. instead of 10:30 p.m., said Jean Parker, Merriweather's general manager. Nearly 14,000 people paid between $22 and $33 to attend Thursday's show. The concert was sponsored by Concerts for the Environment to raise money and consciousness for the environmental cause. The show was the last installment for Earth Day concerts, which also included shows in Los Angeles and New York. As the show progressed after 11:30 p.m., 10 residents called police to complain of noise. Three callers lived on High Wind Court, Jacobs Ladder and Rosinante Run, police said. "People called because the band was playing longer and [they] didn't like being disturbed," said Sgt. Gary L. Gardner, a police spokesman. He said police may meet with management to discuss ways to prevent a repeat and to determine if Merriweather violated its permit. "We weren't in violation at all," Ms. Parker said. "We were well within the county and state ordinances. . . . Unfortunately, it did run late." She said that because the concert took place before the pavilion's usual summertime schedule and on a school night, people may have felt more compelled to call. The show ran late because bands didn't get on and off stage in time, she said. "There were technical difficulties that were causing the artists' egocentric attitudes to prevail," Ms. Parker said without elaborating. An outside promoter was in charge, and Merriweather had no control, she said. When Merriweather workers are in charge, she said, "we try to end them as early as we can." Greg Mellon, assistant director for the county's environmental health department, said he was unaware of the noise complaints, but said music generated from nighttime concerts must be no greater than 55 decibels. Ms. Parker said the musicians complied with the required noise level, but said Thursday night's coolness and humidity may have helped to carry the sound.