This report is the first in a series that will document and reevaluate the trends in the atmospheric deposition problem, especially in regard to implementation of the Clean Air Act Amendments of 1990. This report is organized in four chapters. Each chapter addresses the three issues of acidic, nutrient, and toxic atmospheric deposition in a parallel manner. Chapter 1 provides a brief description of the atmospheric deposition process and its effects on Maryland's aquatic and terrestrial resources. Chapter 2 identifies the sources of atmospheric pollutants affecting Maryland and describes the relative contributions of different industries and geographic regions. Chapter 3 presents the status and trends in atmospheric deposition in Maryland based on a range of studies including analysis of original, long-term data sets from the Chesapeake Bay region. Chapter 4 discusses the regulatory controls and strategies for monitoring, modeling, and mitigating adverse effects on resources that will likely determine the extent of the atmospheric deposition problem in the future.