Introduction

The first chapter of this section described the important issues related to regional and global air quality. Trace gas emissions play a key role in the processes controlling these air quality phenomena and are also an important part of any potential solutions. In some cases, changes in trace gas emissions are due to obvious pollutant sources, including many technological sources. Technological sources include fossil fuel burning, industrial processes, and waste disposal. These sources are the major trace gas contributors in densely populated or industrial areas and also have a strong impact on the global atmosphere. Other sources, including biomass burning and biogenic sources, have a natural component but are strongly influenced by humans. There is widespread concern about the effect of human activities on the chemical composition of the current earth atmosphere. Human activities are the underlying cause of the current increase in pollutant levels on regional and global scales. In order to understand these increases and to predict future changes, we must quantify emissions from various sources and understand the natural and human-influenced processes that control emissions.

This chapter provides an overview of methods that can be used to investigate and monitor trace gas emissions into the atmosphere. Each technique is described in sufficient detail to give a basic understanding of the method and to enable the reader to determine the most suitable method(s) for a particular application. Additional references are provided to give further details on the selected techniques. Methods for measuring wet and dry...