Publisher Summary The need to monitor the impact of activities involving chemicals on the environment may stem from sound management practice or to satisfy a host of specific legal requirements. No prescribed process can be operated without an authorization from the Environment Agency, and air pollutants that must be measured and the frequency of monitoring are set out in the authorization. Compliance with emission limits for municipal waste incineration plants also requires monitoring. Stages in monitoring include obtaining representative samples and subsequent analysis of physical, chemical or microbiological attributes. Monitoring techniques range from sophisticated in-line, continuous sampling and instantaneous analysis linked to audible/visual alarms or features to control the pollution; samplers running continuously, for example, throughout a normal day for subsequent analysis; to grab samples (that is, samples collected over a short time span of, for example, a few minutes).