Robynn Andracsek, P.E., Burns & McDonnell and Contributing Editor
Air permitting people love acronyms. And have you noticed that they all seem to sound the same? You’re not imagining things.
This month we’ll tackle a more lighthearted topic: how to understand the alphabet soup that regulates your power plant’s emissions. Learn a few acronyms. Sound like you know what you’re talking about and impress your boss and coworkers. Be the hit at the next conference. You too can speak in acronym code (see Table 1).
There are subtle differences in the names of these control requirements that give insight as to what level of control is required. Take, for example, the various uses of “available” versus “achievable.” An available control technology is not necessarily the one with the lowest emission rate. You might be allowed to take into account the cost of the technology or if it is commercially available. Contrast “available” with “achievable,” which can be taken to mean the lowest or strictest emission limit found anywhere. “Available” is usually less strict than “achievable.”
Another important difference among control requirements is to understand to which source (or sources) each applies. BACT, NSPS and LAER only apply to newly constructed or modified major sources. In the case of NSPS, “new” is defined by a specific date in each NSPS. Some NSPSs have two sets of “new” sources, based on the date when the NSPS was modified. (See NSPS Subpart Da for an example.) BACT and LAER evolve over time and are redefined with each new construction permit application issued. RACT and BART apply to existing sources and require control device retrofit. MACT, CAIR and CAMR apply to both new and existing sources, but may have different requirements for each. (We’ll ignore for the time being that CAMR is in legal limbo and may go away entirely. Likewise, CAIR is under legal attack and its fate is uncertain.)
Location of Sources
The location of a source can also dictate if a control requirement applies. BACT applies only in attainment areas, LAER and RACT only in non-attainment areas (Figure 1). BART addresses visibility and is only applicable to sources having an influence on visibility in a Class I area. BART-applicable sources are usually within 250 kilometers of one of these areas (Figure 2). However, the case-by-case applicability analysis can extend BART to 400 km or more away from a Class I area.
Each regulation controls a different subset of pollutants. There are seven criteria pollutants:
- Carbon monoxide (CO)
- Particulate matter less than 10 microns in diameter (PM10)
- Particulate matter less than 2.5 microns in diameters (PM2.5)
- Ozone, which is regulated through volatile organic compounds (VOCs)
- Lead (Pb)
- Nitrogen oxides (NOX)
- Sulfur dioxide (SO2).
BACT applies to criteria pollutants for which a source is subject to Prevention of Significant Deterioration (PSD). Similarly, LAER applies to pollutants for which a source is subject to Non-attainment New Source Review (NNSR) and for which the source’s location is out of attainment. RACT addresses pollutants for which an area is out of attainment. MACT applies to hazardous air pollutants (HAPs). Originally, there were 188 HAPs but some have been delisted (for example, methyl ethyl ketone) and some are actually groups of chemicals (for example glycol ethers) CAMR applies only to mercury. CAIR was developed to address PM2.5 non-attainment through its precursors, SO2 and NOX. Finally, each NSPS applies to specific criteria pollutants and sometimes to HAPs.
See, very easy, if you spend all day, every day, reading air pollution control regulations. And, remember, if it doesn’t make sense, then you understand it correctly.
National Park Service, Air Resource Division, October 2002. http://www.epa.gov/ttn/atw/188polls.html