Читать книгу Continuous Emission Monitoring - James A. Jahnke - Страница 30

Title III of the 1990 Clean Air Amendments replaced the previous NESHAP program. Title III identified 189 hazardous air pollutants (HAPs) (later reduced to 187), to be regulated for sources emitting more than 10 tons/year of any one listed pollutant or 25 tons/year of a combination of listed pollutants. EPA has promulgated emission limits and engineering standards for the principal sources emitting HAPS (or “air toxics”). The sources must apply “maximum achievable control technology,” where MACT technology is the best control achieved in practice by 12% of the best controlled similar sources. However, MACT encourages process changes or other pollution prevention activities rather than the application of control equipment.

The air toxics, or “MACT standards,” also incorporate monitoring requirements to determine, on a continuous basis, whether emission limits are being met. Most MACT standards require parameter monitoring, in other words a “continuous parameter monitoring system (CPMS)” that is described in a “monitoring plan,” rather than the installation of CEM systems. However, where control devices are used that can be effectively monitored, such as carbon adsorbers and incinerators, CEM systems are either required or suggested as an alternative to parameter monitoring. The Part 63 Subparts give the emissions standards and monitoring requirements for HAPs emitted from 174 listed industries. Rather than requiring the monitoring of specific pollutants from the list of 187 HAPs, the use of surrogate analyzers is often allowed (such as a particulate monitor to monitor metal emissions or a total hydrocarbon monitor rather than a speciating instrument). Sources required to monitor HAPs and methods used to measure them are discussed further in Chapter 13.