Illinois continues to build a new partnership with USEPA that more clearly focuses on specific environmental progress goals and communicates the results to the public in a clearer and more concise fashion. This Fifth Annual Environmental Conditions Report continues to reflect the performance measurement system jointly adopted by the Environmental Council of States and the USEPA. This fifth report presents information on Statewide nitrogen oxides (NOx) emissions and mobile sources for the first time. These aspects have a major influence on ozone attainment. The authors also continue to see more waterways achieve good condition and to see some reduction in nonpoint source impacts. The population served by safe drinking water supplies decreased slightly due to problems caused by nitrates. The cumulative total area remedied has risen to 37,285 acres, or 39% of our objective for 2005 (95,000 acres). In addition, the backlog of open dump sites needing to be cleaned up has decreased by 25 percent.