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Air Quality Planning

Early Action Compact


Overview of Unifour EAC Program

On December 17, 2004, the North Carolina Department of Environment and Natural Resources (NCDENR), Division of Air Quality (NCDAQ), submitted to the United States Environmental Protection Agency (USEPA) North Carolina’s 8-hour ozone National Ambient Air Quality Standard (NAAQS) attainment demonstration for regions designated as Early Action Compact (EAC) areas.  The EAC areas in North Carolina include the Cumberland County EAC area; the Mountain EAC area (Buncombe, Haywood, and Madison Counties); the Triad EAC area (Alamance, Caswell, Davidson, Davie, Forsyth, Guilford, Randolph, Rockingham, Stokes, Surry, and Yadkin Counties); and the Unifour EAC area (Alexander, Burke, Caldwell, and Catawba Counties). 


Although, the area was designated “non-attainment,” Catawba County and all other government jurisdictions, working under the structure of the Western Piedmont Council of Governments (WPCOG), formed a Unifour Air Quality Committee (UAQC), which has taken proactive measures to inform the public about ozone levels and instruct the community about methods to abate the problem.  The most significant and important measure was to enter into an Early Action Compact (EAC), which is an agreement signed by the EPA, DENR, and all Unifour local governments. The formal document establishes a means for the entire Unifour to come into compliance with Federal EPA ozone standards at an accelerated pace.  By entering into this agreement the Unifour avoided federal penalties until December 2007.  The deferment was conditional upon no milestone being missed by local governments.  If an EAC requirement is not achieved on time, the penalties immediately take effect. 


The Unifour Early Action Compact (EAC) illustrates efforts being made in the Unifour to reduce the formation of ground level ozone pollution. It serves to “facilitate self-evaluation and communication with EPA, NCDENR, stakeholders, and the public” in regards to the EAC program and to promote the program’s goal to achieve cleaner air faster in the Unifour region.  It documents the area’s progress regarding the implementation of local control measures and provides specific information identifying the government agency or department with the responsibility for implementation of each measure.


The local emission reduction strategies were adopted and implemented based on their suitability for addressing ozone pollution from three primary approaches: education / awareness, transportation, and use activities. Throughout the Unifour region there have been widespread efforts towards educating the public and raising awareness about air quality while also suggesting practical methods individuals can use to help improve the region’s ambient air quality. Presentations to school children and elected officials, as well as a sustained media campaign focusing on ozone, have been the foundation of the education/outreach program. Local and regional newspapers, television and radio, and a growing internet presence, have also been useful in making Unifour residents aware about ozone and air quality conditions.


Local Control Measures Implemented in the Unifour

  • Expand the Inspection and Maintenance program for passenger vehicles. Catawba County began July 1, 2003; Burke and Caldwell Counties began July 1, 2005. Authority and responsibility: NCDMV.

  • A New Regional Transit System Implemented. The Greenway Transit System combined four (4) individual providers into one multi-county transit system on July 1, 2008.  All of the fleet’s diesel vehicles use bio-diesel fuel and a hybrid vehicle has been ordered.

  • Promotion of Compressed Work Weeks and Flex-time. All ten members have agreed to promote this measure where practical, which is estimated to reduce NOx by 1.3 tons/year. Authority and responsibility: Local EAC members.

  • Develop Regional Bicycle and Pedestrian Plan. Has been estimated to reduce NOx by 1.6 tons/year and VOCs by 2 tons/year. Greater Hickory MPO/Local EAC members.

  • Outdoor Burning Ban. The NC Environmental Management Commission approved a new rule that bans open burning on "Air Quality Action Days" when the AQI is Code Orange or above. Authority and responsibility: NCDAQ.

  • City and County Energy Plans. An energy conservation plan has been developed and adopted by all ten local EAC members that direct city and county departments to reduce energy consumption and conserve natural resources in an effort to reduce emissions from EGUs. Authority and responsibility: Local EAC members.

  • Alternative Fuel Vehicles and the Clean Cities Program. The UAQC is a Core Stakeholder in the Centralina Clean Fuels Coalition and all members of the EAC are committed to the pursuit and use of alternative fuel technologies. The area has several refueling stations for AFVs including biodiesel, CNG, and ethanol. Authority and responsibility: UAQC, Greater Hickory MPO, and Local EAC members.

  • Support Efforts and Coordination of Metropolitan Planning Organization and Rural Planning Organization. The Greater Hickory MPO and Unifour RPO engage in long range transportation planning to ensure that highway and transit programs conform to the air quality goals established by the EAC. Authority and responsibility: MPO/RPO and local EAC members.

  • Improve Traffic Operational Planning, Engineering, and Maintenance. The City of Hickory optimized its synchronized traffic signals along US 321, McDonald Parkway and Tate Boulevard, effectively increasing traffic flow and reducing congestion. Authority and responsibility: MPO/RPO and local EAC members.

  • Implement Smart Growth, Mixed Use and Infill Development Policies. This measure helps reduce vehicle miles traveled and improve air quality through land use management programs. Several members have adopted land use regulations based upon Smart Growth concepts. Authority and responsibility:  Local EAC members.


  • Air Awareness Program. All local members participate in the Air Awareness program and have adopted "Ozone Action Plans" that include provisions to help reduce ozone formation. Authority and responsibility: UAQC and local EAC members.

  • Adopt a Local Clean Air Policy. Local stakeholders promote air quality awareness and work to minimize ozone pollution in their respective local communities. Authority and responsibility: Local EAC members.

  • Air Quality Contacts for Each Local Member of the EAC. Contacts disseminate information to local governments and assure adherence to goals of the EAC program. Authority and responsibility: Local EAC members.

  • Landscaping Standards and Urban Forestry. Implementation throughout Unifour to help mitigate the effect of the “Urban Heat Island” and promote energy conservation and reduce emissions. Authority and responsibility:  Local EAC members.


Every milestone requirement in the Unifour EAC has been met within appropriate time frames. In fall 2007, the EPA announced that 14 regions around the U.S. (who had entered into EAC’s) were ahead of schedule for ozone level reductions, the Hickory/Catawba County Unifour area was one of those recognized for its efforts in accomplishing a reduction.

Source Apportionment Study


Attaining Pollution Standards in Catawba County

During the fall of 2006 and early winter of 2007, the Western Piedmont Council of Governments (WPCOG) sponsored a study to determine the sources of and control strategies for fine particulate matter, known commonly as PM2.5. The concern motivating the study was prompted by CatawbaCounty being designated as a non-conforming area for the pollutant by the U.S. Environmental Protection Agency (USEPA). The USEPA is responsible, based in part upon recommendations from each state’s governor, for designating areas not in compliance with PM2.5 pollution standards established by the National Ambient Air Quality Standards (NAAQS) under Section 107(d) of the Clean Air Act and later amendments.


Once an area has been designated as non-attainment with regard to USEPA standards for a controlled pollutant, the area’s local and state governments typically respond to have the designation overturned or lessened (geographically in size or in severity of the designation), or, if it is clear that the designation cannot be ameliorated, they must work to develop and implement a plan to bring the area back into attainment with the national standard. In the current case, the first action was to have the initial USEPA-recommended non-attainment area reduced from four counties to just one: Catawba.


The technical data employed byNorth Carolinawas sufficient for USEPA to reduce the non-attainment area from four counties to one county. Two other counties inNorth Carolina(Davidson andGuilford) also fell into non-attainment.


The Monitoring Site Location 

This sensitivity to the new standard in Catawba County expressed itself most clearly by the local governments’ strong belief that the siting of the Hickory monitoring device, known as the Hickory Water Tower monitoring site, was not representative of the region’s overall characteristics. Several actions challenging the validity of the location and/or data readings taken at the site took place between the time that the Catawba County designation took effect and the WPCOG hired a consultant to study the sources and control measures of PM2.5.


The first of these challenges was to ask North Carolina Department of Environment and Natural Resources, Division of Air Quality (NCDAQ) to place a second monitor within approximately one mile of the water tower site to determine if the second monitor (located at the Hickory Rescue Squad) would show lower readings than the Water Tower location.  For each quarter between July 2004 and June 2006 the rescue squad monitor PM 2.5 levels were lower than the water tower monitor readings, indicating that localized events could be impacting the monitor at the water tower. In December 2005 the Unifour Air Quality Committee (UAQC) asked for an EPA audit of both of the rescue squad and water tower monitors.  The audit was completed in March 2006.  The EPA auditors concluded that both sites “technically” met the EPA siting criteria.  They also concluded, however, that local impacts could adversely be affecting the results at the water tower monitor.


Based on the conclusions of the audit and the two monitor comparisons, the UAQC sent out a Request for Proposals in May 2006 to determine the source apportionment of the water tower PM2.5 monitor.  In July 2006, the Louis Berger Group, Inc. was asked to conduct the study.  The following is a list of measures that were a result of that study.



Table 1. Local Mitigation Measures for PM 2.5 Source

It is highly unlikely that any of these strategies will make a significant impact at the Hickory site in terms of reducing PM2.5 concentrations. In fact, the combination of cleaner fuels; activation of smokestack controls at the Marshall coal-fired power plant, and more stringent inspection/maintenance requirements will prove to be of the greatest benefit and may in fact reduce PM2.5 readings at the monitoring site below the existing annual and daily thresholds set by the US Environmental Protection Agency. The figure 5 at the top of this page indicates the relative percentages of PM2.5 by estimated source type.


However, a combination of local mitigation strategies can make a measurable impact that, in turn, would provide an additional surety that Hickory, Catawba County, and the Unifour Region are doing everything possible to reduce PM 2.5 emissions. It is also possible that (a) the existing National Ambient Air Quality (NAAQS) standards will change again, as they have recently for the daily standard; or (b) the existing local and statewide measures listed in Figure 1 will not be sufficient to push the PM 2.5 monitor readings below the attainment threshold.

Unifour Strategic Air Quality Plan


On September 21, 2010, The UAQC adopted the Unifour Air Quality Plan. The plan itself contains air quality data, history, and a wealth of other information that pertains to air quality in the Unifour Region.  Listed below is the Implementation section of the Plan.

The Unifour Strategic
Air Quality Plan

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