In 2000, under Whitman's leadership, New Jersey's violation of the federal one-hour air quality standard for ground level ozone dropped to 4 from 45 in 1988. Beach closings reached a record low, and the Natural Resources Defense Council recognized New Jersey for instituting the most comprehensive beach monitoring system in the country. New Jersey implemented a new watershed management program, and became a national leader in opening shellfish beds for harvesting. Whitman agreed to give tax money to owners of one million acres (4,000 km²) or more of open space and farmland in New Jersey.