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
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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 by North Carolina was sufficient for USEPA to reduce the non-attainment area from four counties to one county. Two other counties in North Carolina(Davidson and Guilford) 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.
Air Awareness
The North Carolina Air Awareness Program is a public outreach and education program of the North Carolina Division of Air Quality. The goal of the program is to reduce air pollution though voluntary actions by individuals and organizations. For the past decade NCDAQ has supported and collaborated with local Air Awareness Coordinators throughout the state including the Unifour Area. Until recently the UAQC participated without outside funding to support education and outreach efforts. However in 2009, UAQC was awarded $20,000 per year for three years from a DAQ federal CMAQ funding to support the local education and outreach efforts.
Statewide Campaigns
The North Carolina Air Awareness Program is a public outreach and education program of the North Carolina Division of Air Quality. The goal of the program is to reduce air pollution though voluntary actions by individuals and organizations. The program seeks to educate individuals about the sources of air pollution and explain how the health effects of air pollution can be minimized by modification of outdoor activities on ozone action days. In addition, the program aims to inform the public of ways to minimize production of air pollutants to improve air quality over time.
In addition to being a partner in the Greater Hickory/Unifour area, N.C. Air Awareness has local programs in the Triangle, the Triad, the greater Charlotte area, Fayetteville and the Asheville area.
NCDAQ works closely with local air agencies and Councils of Government to accomplish program goals. Although some program activities are centrally coordinated from the NCDAQ Raleigh Central Office, locally based area coordinators direct most local program activities. In the Triad and Charlotte areas, the local Air Awareness Programs are housed in the Forsyth County Environmental Affairs Department (FCEAD) and the Mecklenburg County Air Quality agency, respectively. In Asheville and the Triangle, local programs are housed at the NCDAQ Asheville Regional Office and the NCDAQ Central Office.
Program Components
The AQ Forecast: The most visible element of the program is the AQ forecast, seen by a large segment of the public on local TV news weather segments. Expected pollutant levels, in terms of color code and Air Quality Index (AQI) number, are forecasted year around by NCDAQ meteorologists. These forecasts are distributed to local media (television, radio, and newspaper) and to area businesses and individuals. The forecast is also displayed on the NCDAQ web page. Separate forecasts are issued for the Triangle, Charlotte, Hickory, Rocky Mount, Fayetteville and Asheville. The FCEAD issues air quality forecasts for the Triad.
School-Based Outreach: Program staff conduct educator-training workshops. Workshop participants can earn credit toward Environmental Educator certification (through NC Office of Environmental Education) as well as continuing education credits. Program staff also give classroom presentations at area schools. To learn more about school outreach programs, contact Doug Wise at 828.485.4283.
Regional Air Quality Coalitions: As Coalition members, area business, agencies and organizations multiply NCDAQ's education efforts by distributing the ozone forecast to employees and providing education about air quality. Regional Coalitions in Asheville, Hickory, the Triad, Charlotte and the Triangle count over 500 businesses and organizations statewide.
Public outreach: The North Carolina Air Awareness Program utilizes a wide range of web and media outlets to broadcast our message to the general public. These include statewide radio messages covering open burning, idle reduction, clean air tips and much more. Through both local coordinators and state representatives, our program regularly exhibits at health, environmental, and state fairs and festivals. Public information is distributed through the program website, daq.state.nc.us/airaware and the toll-free air quality hotline 1-888-RU4NCAIR. Information may also be obtained by emailing air.awareness@ncdenr.gov.
Know the Code Campaign
The Air Quality Index (AQI) is an index for reporting daily air quality. It tells you how clean or polluted your outdoor air is, and what associated health effects might be a concern for you. The AQI focuses on health effects you may experience within a few hours or days after breathing polluted air. EPA calculates the AQI for five major air pollutants regulated by the Clean Air Act: ground-level ozone, particle pollution (also known as particulate matter), carbon monoxide, sulfur dioxide and nitrogen dioxide. For each of these pollutants, EPA has established national air quality standards to protect public health.
AirNow Web Site
The AIRNow Web site (run by EPA) provides the public with easy access to national air quality information. The Web site offers daily AQI forecasts as well as real-time AQI conditions across the US, and provides links to more detailed State and local air quality Web sites.
EnviroFlash
EnviroFlash is a new electronic information system designed to communicate environmental issues to the public. EnviroFlash is a partnership between the U.S. Environmental Protection Agency and state and local air quality agencies.
EnviroFlash provides you with timely air quality information that you can use to plan your daily activities and protect your health. With EnviroFlash, you have complete control of your forecast subscription. Subscription is fast and easy, and you decide which forecasts to receive. You can change or discontinue your subscription at any time through the automated EnviroFlash web page at www.enviroflash.info.
The forecasts are developed daily by staff meteorologists at the North Carolina Division of Air Quality, just as they have been since 1998. These are the same forecasts you might see in your newspaper or on your local TV weather report.
Anti-Idling
Unnecessary idling wastes fuel, costs money and pollutes the air. NCDAQ had developed several initiatives to reduce idling of all diesel and gasoline vehicles.
Passenger Vehicles Program: Turn Off Your Engine “Breathe Better, Save Money”
This is a voluntary campaign aimed at protecting people's health and the environment, especially children and people with respiratory problems, by reducing vehicle emissions which are one of the main contributors to air pollution in our region. Learn how you can receive signs for parking lots and information for your organization or school.
Heavy-Duty Truck Rule
In 2010, the N.C. Environmental Management Commission (EMC) adopted the Heavy Duty Diesel Truck Rule as part of the state’s efforts to reduce air pollution, protect public health and meet more stringent federal air quality standards. The rule requires operators of heavy-duty trucks to reduce unnecessary idling in North Carolina. The commission sought input from truckers, shipping companies and other stakeholders in developing the rule, and more than 20 states have similar rules.
Idling vehicles are significant sources of air pollution. The state Division of Air Quality estimates the rule will reduce nitrogen oxide (NOx) emissions, the primary cause of ozone in North Carolina, by up to 1,300 tons per year statewide. In comparison, a moderate-sized coal-fired power plant typically emits about 500 tons of NOx a year. The rule could reduce emissions of carbon dioxide, the most common greenhouse gas, by as much as 100,000 tons per year. Exhaust from idling vehicles also contains fine particles and toxic air pollutants that can pose health risks for truckers and other people at highway rest areas, truck stops and other places where idling vehicles congregate.
Operators could save a lot of fuel and money by complying with the idle rule. A heavy-duty vehicle typically burns about one gallon of fuel per hour while idling. DAQ estimates the idle rule will save up to 9 million gallons of fuel per year statewide.
Who must reduce idling?
The idle-reduction rule applies to on-road gasoline and diesel-powered vehicles with loaded weights greater than 10,000 pounds. Under the rule, operators should not idle their vehicles more than five consecutive minutes in any 60-minute period except for certain cases dealing with safety, health and economic concerns.
The rule makes allowances for cases when idling may be necessary. For example, operators of emergency vehicles such as fire trucks can idle while responding to emergencies or during training exercises. Heavy-duty vehicles can idle when it’s necessary to operate equipment that depends on their engines, such as hoists and refrigerators.
Options for idle reduction
The easiest way to reduce idling is simply to turn off your engine. However, DAQ recognizes that vehicle operators often idle their engines for legitimate reasons, such as providing power for air conditioners, refrigerators and other equipment. Truckers can avoid much idling by stopping at truck stops that provide electricity and other services.
Another alternative is to install auxiliary power units, or APUs, to provide the electricity needed to run air conditioners and other equipment. Even though APUs can cost as much as $10,000 to install in a truck, DAQ estimates that the fuel and wear-and-tear savings from reduced idling would offset those costs in about one to two years for most trucks, depending on fuel costs. DAQ may have grant money available for operators who install APUs. More information about APUs and possible rebates can be found on the DAQ website: www.ncair.org/motor/Rebates/
DAQ and the local air awareness coordinators are focusing on education and outreach to achieve compliance with the idle rule for heavy-duty vehicles. However, as with an air quality rule, DAQ has the authority to levy fines. The division anticipates that most enforcement actions would be complaint-driven. Citizens can report suspected case of unnecessary idling on the DAQ website: www.ncair.org/motor/
The purpose of the idle reduction signage is to reduce pollution from idling buses and cars that negatively affect a child’s healthy lung growth and development. Children are more vulnerable to the impacts of vehicle pollution than other populations.
Most of our air quality problems in North Carolina are mobile source related. Vehicle emissions are the number one source of air pollution in many areas in North Carolina. When a car is idling, it's also polluting. Idling wastes money and natural resources. It can damage vehicles, pollute the air and harm our health. Our voluntary program is aimed at distributing free signs and materials to partners interested in keeping unnecessary idling under control in their parking lot and pick-up areas.
During 2009-2010 all public schools in the region were provided one to two signs per school. School district staff mounts signs on existing posts or walls.
Curriculum utilized in conjunction with Anti-Idling:
1st Grade, Ready, Set, Stop Idling: Students learn what is good and bad for the air by watching a video clip, taking part in a card activity, acting like cars and drawing and writing about idling.
2nd Grade, Make a Good Choice: Choose No Idling: By creating posters and t-shirts and reading a book, students explore how making good choices can help the environment while bad choices do the opposite.
Grades 3 – 5, Idlers: Please Stop Your Engines: After collecting idling data at school for one week, students make graphs using the information and slogans for mock no-idle bumper stickers. Please Do Not Make Us Cough, Turn Your Engine Off. Students complete graphic and writing organizers to prepare for a persuasive essay that educates and creates awareness about the harmful effects of idling and persuades others to stop idling.
Unifour Air Quality Committee
The Unifour Air Quality Committee (UAQC) is made up of stakeholders from the private and public sector that are dedicated to improving the air quality in the Unifour area. The Unifour Air Quality Oversight Committee (UAQOC) members are comprised of ten elected officials from the Unifour (Alexander County, Town of Taylorsville, Burke County, City of Morganton, Caldwell County, City of Lenoir, Catawba County, City of Conover, City of Hickory, and City of Newton). The UAQOC was formed to make policy and financial decisions for regional air quality activities. Staff support for the UAQC and UAQOC is provided by the Western Piedmont Council of Governments (WPCOG). Funding for the UAQC/UAQOC activities is provided by the Greater Hickory Metropolitan Planning Organization (GHMPO), the Unifour Rural Planning Organization (URPO), and occasional assessments of the 28 local governments in the region (based on population).
History of the UAQC/UAQOC:
In January 1999 the WPCOG learned that Unifour Region’s ozone levels would violate the new EPA 8-Hour Standard. The following spring and summer public meetings were held with local governments, the North Carolina Division of Air Quality (NCDAQ), Economic Development Corporations, Chambers of Commerce and other interested groups. In November 1999 the Catawba Air Quality Committee (CAQC) was formed. During the next four years the CAQC was expanded to include other regional members to form the Unifour Air Quality Coalition. The coalition eventually evolved into more formal Unifour Air Quality Committee (UAQC) and the Unifour Air Quality Oversight Committee (UAQOC) which is made up of stakeholders and elected officials from throughout the region.
UAQC/UAQOC Accomplishments and Commitments:
The UAQC and UAQOC meet monthly and are committed to improving air quality in the region through various strategies. Measures already taken include:
Unifour Early Action Compact (EAC) - In December 2002 the UAQC/UAQOC assisted in an agreement between Federal, State, and Local governments to address ozone pollution in a more expedient manner than what is required in the Clean Air Act through an Early Action Compact (EAC). The Unifour EAC has been recognized by EPA as one of the most successful programs in the United States.
Hiring Technical Consultants - the UAQC/UAQOC gets assistance from consultants to provide guidance and expertise to the committee. For example, the UAQC/UAQOC commissioned a study with the Louis Berger Group to determine the local causes of PM 2.5 in the Unifour Area.
Air Awareness Programs - The North Carolina Air Awareness Program is a public outreach and
education program of the North Carolina Division of Air Quality. The goal of the program is to reduce air
pollution though voluntary actions by individuals and organizations. For the past decade NCDAQ has
supported and collaborated with local Air Awareness Coordinators throughout the state including the Unifour Area. WPCOG staff acts as regional Air Awareness Team members in conjunction with NC DAQ’s Air Awareness Program, providing air quality outreach to the region, including students, teachers and the general public.
Unifour Strategic Air Quality Plan –The WPCOG completed the Air Quality Plan in 2010. The UAQC wanted to build on all of the previous work by having a regional planning document that laid out ongoing strategies to improve air quality.
Presentations - Unifour Air Quality Committee
Air Quality & Emissions
Fine Particulate (PM 2.5) Monitor Readings
The NC Division of Air Quality (DAQ) is required to evaluate fine particle pollution (known as PM 2.5) to determine if Catawba County is in attainment for the federal standards for PM 2.5. Specifically, NCDAQ evaluated the following data yearly as part of the air quality analyses:
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Annual PM 2.5 Averages – Average daily reading during the course of one calendar year. PM 2.5 monitor readings usually are taken and analyzed every third day during the course of a year.
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PM 2.5 3-year Averages – Average of the last three years, used to determine change over longer periods of time.
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PM 2.5 98th Percentile Daily Reading – 3rd or 4th highest reading during the course of a year. PM 2.5 monitor readings usually are taken and analyzed every third day during the course of a year.
Due to the population size of the Hickory-Lenoir-Morganton Metropolitan Statistical Area (MSA), the region is required by the US Environmental Protection Agency (USEPA) to have one PM 2.5 monitor. The monitor is located one block west of US 321 close to the water tank owned by the City of Hickory. Additional monitoring related to the official monitor is also taking place on the site.
The PM 2.5 federal standard is a three-year average of annual PM 2.5 monitor readings. A violation occurs if a PM 2.5 monitor exceeds the standard. The Federal standard for PM 2.5 until 2012 was 15 micrograms per cubic meter. The standard was lowered in December 2012 to 12 micrograms per cubic meter.
Annual PM 2.5 Averages
Table 1 shows the yearly readings for the Hickory monitor between 2004 and 2014. The design values are presented in micrograms per cubic meter, with values exceeding the standard highlighted with grey shading and bold lettering.
In 2005 and 2006 the Hickory PM 2.5 monitor recorded violations of the standard. Data in Table 1, however, shows significant decreases in PM 2.5 design values since 2006 in the region, which can be attributed to multiple factors, including traffic improvements, mobile source emission reductions, alternative fuels and technologies, the addition of pollution control scrubbers at the Marshall Steam Station (coal fired electric power plant owned by Duke Energy that located in southeastern Catawba County), more favorable weather patterns and poor economic conditions. As a result of these factors, annual PM 2.5 readings at the Hickory Water Tower Monitor have been less than 10 micrograms per cubic meter since 2012.
PM 2.5 3-year Averages
The PM 2.5 three-year average is a health based standard that is used to see how air quality conditions are changing over time. It is calculated by averaging the annual value for three years. Since the design value is an average of three years, a decrease may be the result of one really good air quality year; or conversely, an increase may be the result of one bad air quality year. Therefore, looking at the trends of the 3-year average can give insight as to how the air quality in an area is improving.
In December 2004 USEPA placed all of Catawba County in “non-attainment status” for PM 2.5 based on the three-year average between 2001 and 2003 being slightly above the 15.0 standard. Table 2 displays the 3-year averages for the Hickory PM 2.5 monitor between 2004 and 2014. Results show that the monitor was in nonattainment for the 15 micrograms per cubic meter PM 2.5 standard through 2005-2007. Over the past decade PM 2.5 levels at the Hickory monitor have fallen substantially. As a result of improving PM 2.5 levels, in December 2011 Catawba County was moved out of nonattainment status by USEPA and was placed instead in “maintenance (attainment) status.” The 2011-2013 and 2012-2014 three-year averages for the Hickory PM 2.5 monitor were less than 10 micrograms per cubic meter.
PM 2.5 98th Percentile Daily Reading
Besides setting an annual standard, USEPA also has a daily PM 2.5 standard to protect public health. The annual federal standard, established in 2006, is 35 micrograms per cubic meter. The standard is calculated at the 98th percentile for each year (USEPA uses a three-year average for the standard), which is equivalent to 3rd or 4th highest daily reading during the course of a year (PM 2.5 monitor readings usually a taken and analyzed every third day during the course of a year). The PM 2.5 98th percentile daily reading has been below the standard every year except in 2005 (Table 3). The three-year average has never violated the daily standard.
Ozone Monitor Readings
The NC Division of Air Quality (DAQ) is required to evaluate design value (DV) trends and ozone exceedance trends to determine if any of the State’s monitors show increases in ozone formation. Specifically, the NCDAQ evaluates the following data as part of the air quality analyses:
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8-hour Ozone Design Value Trends – Most recent design values (1 and 3 year average of the 4th highest 8-hour ozone average), compared to the trend in design values from the 2005 timeframe to present.
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8-Hour Ozone Exceedances – Number of exceedances of the 8-hour ozone standard at each monitor in the EAC areas for the most recent ozone season, compared to the number of exceedances at each monitor from 2005 to present.
Due to the population size of the Hickory-Lenoir-Morganton Metropolitan Statistical Area (MSA), the region is required by the US Environmental Protection Agency (USEPA) to have two ozone monitors. The monitors are located in Alexander County (Taylorsville) and Caldwell County (Lenoir).
The ozone federal standard is a three-year average of the fourth highest daily 8-hour ozone monitor reading. A violation occurs if an ozone monitor exceeds the standard. The Federal standard for ozone until 2008 was 85 parts per billion (ppb). The standard was lowered in 2009 to 75 ppb. In October 2015 the ozone standard was lowered again to 70 ppb.
8-hour Ozone Design Value Yearly Trends
Table 1 below shows the trend in 8-hour ozone values at monitors in Alexander and Caldwell County. The design values are presented in ppm, with design values exceeding the standard highlighted in gray with bold lettering.
*2015 data is preliminary and not been varied by USEPA. Source: USEPA and NC Division of Air Quality, 2018.
Data in Table 1 shows significant decreases in ozone design values over the past decade in the region, which could be attributed to multiple factors, including traffic improvements, mobile source emission reductions, alternative fuels and technologies, more favorable weather patterns, and poor economic conditions.
8-Hour Ozone Exceedances
No daily 8-hour ozone exceedances have occurred over the past decade at either the Alexander County or Caldwell County monitor.
4th Highest Value Trends
The design value is calculated by averaging the 4th highest 8-hour ozone value for each of three years. Since the design value is an average of three years, a decrease may be the result of one really good air quality year; or conversely, an increase may be the result of one bad air quality year. Therefore, looking at the trends of the 4th highest value can give insight as to how the air quality in an area is improving.
Table 2 displays the 4th highest daily 8-hour ozone 3-year averages for the region. Three year averages at both monitor locations have been decreasing since 2005. The 2013-15 4th highest daily 8-hour ozone monitor averages are currently well below the current federal standard of 70 parts per billion.
