- The Clean Air Act sets NAAQS for six principal pollutants considered harmful to public health.
- At the recommendation of the Clean Air Scientific Advisory Committee, EPA has recently promulgated regulations that lower allowable concentrations for these pollutants.
- For those plant owners and operators who operate fuel burning equipment such as large boilers or furnaces or processes that generate pollutants, take note that these changes.
Many plant owners and operators are bracing for the biggest changes to the National Ambient Air Quality Standards (NAAQS) since the Clean Air Act was first enacted in 1972. Those who are unprepared could face significant permitting challenges.
The Clean Air Act sets NAAQS for six principal pollutants considered harmful to public health. These include carbon monoxide, lead, nitrogen dioxide (NO2), ozone, particulate matter less than 10 microns and 2.5 microns (PM10 and PM2.5), and sulfur dioxide (SO2). At the recommendation of the Clean Air Scientific Advisory Committee, EPA has recently promulgated regulations that lower allowable concentrations for these pollutants. The installation of new equipment or significant modifications to existing equipment requires a demonstration of compliance with the more stringent NAAQS as part of an air permit application prior to constructing or modifying these emission sources.
For those plant owners and operators who operate fuel burning equipment such as large boilers or furnaces or processes that generate these pollutants, take note that these changes, particularly those to the NO2 and SO2 standards, have tremendous permitting implications. However, a little upfront planning and a comprehensive look at five basic strategies can help achieve compliance within reasonable time and cost.
One-hour standard adjustments
EPA first adopted the NAAQS for criteria pollutants in the early 1970s, setting both a primary standard to protect health and a secondary standard to protect the public welfare. For NO2 , the standard was set at 0.053 parts per million (53 ppb), averaged annually. In 2010, EPA established a new one-hour NO2 standard at a level of 100 ppb and retained the annual average NO2 standard of 53 ppb.
Similarly, EPA first set the NAAQS primary 24-hour standard for SO2 at 140 ppb and an annual average standard at 30 ppb to protect public health. EPA also set a three-hour average secondary standard at 0.5 ppm to protect public welfare. In 2010, EPA revised the primary SO2 standard by establishing a new one-hour standard at a level of 75 ppb and revoked the two existing primary standards (the 24-hour and annual).
For owner/operators seeking to obtain air construction permits for new or modified equipment, the shorter, one-hour averaging period can be challenging, as there are peaks and fluctuations in emissions during equipment startup and operation that could previously be averaged over a year. Likewise, background ambient one-hour concentrations that must be added to concentrations from the facility’s emissions for the compliance demonstration could have peaks, depending on the location of the facility and the background monitoring data used. Thus, where compliance could previously be demonstrated by averaging concentrations over the period of a year, the one-hour standards must account for peaks associated with both equipment emissions and ambient background emissions.
Assessing attainment status
When a region within a state is designated as “nonattainment” with a NAAQS, the state regulatory authority must prepare a state implementation plan (SIP) that lays out the means for bringing the area into compliance. The repercussions of nonattainment for a state or region are great.
One year from the date of a nonattainment designation, federally funded highway and transit projects will not be allowed to proceed unless the state demonstrates there will be no increase in emissions associated with the projects. State authorities usually target manufacturing facilities to ratchet down emissions, and owners/operators of emission sources will often be subject to more restrictive permitting requirements. In order to obtain an air permit, new and upgraded facilities that are classified as “major stationary sources” located in or near nonattainment areas are required to install lowest achievable emission reduction (LAER) for equipment/processes. LAER is the most effective emissions reduction controls without consideration of cost. In addition, mandatory emissions offsetting could be required. Prior to permitting the construction of new facilities, a state must offset any emissions increases by achieving reductions at existing facilities.
States are currently making changes to the network of ambient monitoring equipment and collecting ambient data to determine the attainment status with respect to the new standards. Since the one-hour standards are a new requirement, there is uncertainty as to the compliance status of a region with the NO2 and SO2 NAAQS.