Alternative Fuels as a Means to Reduce PM2.5 Emissions at Airports (2012)

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Airport Cooperative Research Program Project ACRP 02-23: Alternative Fuels as a Means to Reduce PM2.5 Emissions at Airports 10 CHAPTER 1: BACKGROUND AIRPORTS AND AIR QUALITY Airport managers, environmental agencies and others in the aviation industry are becoming increasingly aware of the contribution of airport-related activities to local and global air quality. Concerns about air quality may impact the review and approval process for airport development projects. Local air quality is affected by air emissions of pollutants associated with sources at an individual airport. Global air quality generally refers to greenhouse gases and their climate change. For local air quality, the National Ambient Air Quality Standards (NAAQS) criteria pollutants include ozone (with the associated precursors volatile organic compound (VOC) and oxides of nitrogen (NOx) emissions), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), course particulate matter (PM10), fine particulate matter (PM2.5), and lead (Pb). This report focuses on the emissions and local impacts of PM2.5 Particulate matter is generally designated as PM in the context of airports. 10 (coarse), PM2.5 (fine), and PM0.1 (ultra-fine), where the number refers to the particle size (aerodynamic diameter that characterizes the size distribution of the aerosol fraction). The smaller the particle, the more likely it is that it will become lodged in the lungs and, therefore, cause health problems. The smallest particle size for which there is a U.S. Environmental Protection Agency (EPA) health-related standard is PM2.5. Those standards have driven data collection for PM2.5. Therefore, emissions measurements and ambient concentration data for PM2.5 are available. There is now increasing concern about ultra- fine particles (PM0.1 Recent studies of emissions from aircraft jet engines show that PM ), but because an ambient standard has not been set, there is less understanding in the scientific community and data are not as available. 0.1 may be the dominant particulate matter emissions of concern in contrast to other sources. However, as discussed previously, for PM0.1, there are no ambient air quality standards and very little data that can be used to underpin particulate matter and research into alternative fuels. Therefore, this Airport Cooperative Research Program (ACRP) research project, ACRP 02-23, has concentrated on PM2.5, while acknowledging that PM0.1 emissions are also of health concern. Alternative fuels that have beneficial impacts with regard to PM2.5 emissions are also likely to contribute to reductions in PM0.1 PM emissions. 2.5 in the atmosphere arises from primary and secondary sources. For this research, primary sources are considered to result in the direct emission of particulate matter into the atmosphere and typically include sources related to fuel combustion. Primary particulate matter from fuel combustion can be measured at the point of emission (e.g., exhaust, stack exit), and includes volatile and non-volatile components. Sometimes, the volatile components of particulate matter emissions are referred to as secondary emissions, but they should not be confused with secondary atmospheric particulate matter. Secondary atmospheric particulate matter sources include chemical reactions with other pollutants (e.g., SO2, NOx, and ammonia) in the atmosphere to form solid sulfates and nitrates, as well as the oxidation of non-methane VOCs (NMVOCs) to form organic aerosols. These interactions may take minutes or days, and the effects can be seen hundreds of miles from the point of release.

Airport Cooperative Research Program Project ACRP 02-23: Alternative Fuels as a Means to Reduce PM2.5 Emissions at Airports 11 Due to the potential confusion over the term “secondary particulate matter,” the following definitions are used for the ACRP 02-23 project: • Non-volatile emissions: Sometimes referred to as “primary emissions,” these are mostly carbon-related emissions (soot). • Non-fuel primary emissions: These relate to brake wear, tire wear and dust type emissions, and are not the primary concern of the ACRP 02-23 project (which is related to fuel use). • Volatile emissions: Sometimes referred to as “secondary emissions,” these are particulate matter “emissions” that form close to the point of release for a particular source and are typically related to the sulfur and hydrocarbon content of the fuel. • Secondary particulate matter: This refers to secondary atmospheric particulate matter unless explicitly stated as referring to an emission. PARTICULATE MATTER AMBIENT STANDARDS Through the Federal Clean Air Act (CAA), the EPA has promulgated NAAQS for several criteria air pollutants. The primary standards are ambient (outdoor) levels of pollutants established to protect public health. Secondary standards are levels set to protect the public welfare and the environment (e.g., visibility, vegetation, deterioration of buildings). On a nationwide basis, the current 24-hour NAAQS for PM2.5 is 35 μg/m3 and the annual standard is 15 μg/m3 Table 1. summarizes the current NAAQS for PM2.5. It should be noted that the EPA is making recommendations to reduce the PM2.5 Table 1 – Nationa l Ambien t Air Quality Standa rds fo r PM NAAQS (U.S. EPA, 2011b). Pollutant 2.5 Primary Standards Secondary Standards Level Averaging Time Level Averaging Time Fine Particulate Matter (PM2.5 15 µg/m ) Annual* (arithmetic mean) 3 Same as Primary Standards 35 µg/m 24-hour† 3 Same as Primary Standards * To attain this standard, the 3 year average of the weighted annual mean PM2.5 concentrations from single or multiple community-oriented monitors must not exceed 15 µg/m3 † To attain this standard, the 3 year average of the 98th percentile of 24-hour concentrations at each population- oriented monitor within an area must not exceed 35 µg/m3 Source: U.S. EPA, 2011a (effective December 17, 2006) The “averaging time” for each NAAQS is based on the time over which sensitive members of the population would be affected detrimentally (e.g., 1 hour, 8 hours, 24-hours, and annual average). Averaging times depend on the pollutant’s physical and chemical characteristics as well as the weight of toxicological and epidemiological evidence supporting the NAAQS. Notably, individual states are allowed to supplement the NAAQS with additional or more stringent state level, air quality standards. NON-ATTAINMENT AREAS The EPA requires that state or regional air quality agencies install and maintain ambient air monitoring networks to identify areas in the U.S. that are in violation of the NAAQS. A geographic area possessing ambient concentrations of an EPA regulated pollutant in excess of the NAAQS is considered “non-attainment” of that NAAQS, and an area possessing ambient concentrations below the applicable NAAQS is considered “attainment”. As the PM2.5 standard

Airport Cooperative Research Program Project ACRP 02-23: Alternative Fuels as a Means to Reduce PM2.5 Emissions at Airports 12 is relatively new, no areas have been re-designated as attainment, but some are subject to a maintenance plan due to a recent past exceedance. Figure 4 and Figure 5 (U.S. EPA, 2011c) show areas of the U.S. currently in violation of the annual and 24-hour PM2.5 More than 50 commercial service airports in the U.S. are located in PM standards, respectively, based on recent air monitoring data (U.S. EPA, 2010b). 2.5 non-attainment areas. Over time, additional locations may be subject to PM2.5 non-attainment designations because the standards are often tightened following the NAAQS review every five years. Airport development projects located in non-attainment or maintenance areas must be shown to conform to the applicable state’s plan for compliance with the Clean Air Act before they can be approved by the Federal Aviation Administration (FAA). The general conformity regulations specify the steps for considering emissions. The first step is to determine the “applicability” of the regulation. It involves comparing project-related emissions to a de minimis threshold. A de minimis threshold of 100 tons per year is defined for PM2.5 Of note, airports tend to contribute only a small amount to an area’s overall emissions. . If emissions exceed this threshold, a full determination is required, possibly with consideration of mitigation options. Table 2 presents the airport (from Chapter 6) and metropolitan statistical area (MSA) (U.S. EPA, 2002a) emissions for the airports included in the ACRP 02-23 project. Tab le 2 – Airport and Reg ional Em is s ion s Airport Airport in non-attainment Area? MSA PM2.5 Airport PM Emissions (Tons), A 2.5 B emissions (Tons), Ratio of B/A Hartsfield-Jackson Atlanta International Airport (ATL) Yes 45,800 63.0 0.0014 Las Vegas McCarran International Airport (LAS) No 12,701 34.6 0.0027 Philadelphia International Airport (PHL) Yes 18,084 44.3 0.0024 San Diego International Airport (SAN) No 17,804 13.1 0.0007 Manchester-Boston Regional Airport (MHT) No 9,527 3.7 0.0004 Source: MSA data (U.S. EPA, 2002a).

Airport Cooperative Research Program Project ACRP 02-23: Alternative Fuels as a Means to Reduce PM2.5 Emissions at Airports 13 Figure 4 – PM2.5 Source: Green Book Non-attainment Areas for Criteria Pollutants, U.S. EPA (2011c) Non-Atta inment Areas a s o f Decem ber 2010 (Annua l S tand ard) Figure 5 – PM2.5 Source: Green Book Non-attainment Areas for Criteria Pollutants, U.S. EPA (2011c) Non-Atta inment Areas a s o f April 2011 (24-hour Stand ard)

Airport Cooperative Research Program Project ACRP 02-23: Alternative Fuels as a Means to Reduce PM2.5 Emissions at Airports 14 IMPLICATIONS FOR AIRPORTS Proposed improvement projects at Los Angeles International and Philadelphia International airports are facing heightened agency review because of the potential impacts of added airport capacity to local and regional PM2.5 air quality. Other airports around the country (e.g., Chicago O’Hare International, Seattle-Tacoma International, George Bush Intercontinental/Houston) have experienced similar public concerns about the potential health effects associated with the combustion of jet fuel, principally due to emissions-related to particulate matter. Expansion projects at other airports to address capacity needs will likely face increased pressure to consider the impacts of particulate matter and emissions of related local pollutants. One of the ways in which airports can assist in reducing PM2.5 AIRPORTS AND ALTERNATIVE FUELS impacts is by increasing the availability and use of alternative fuels. Other strategies to address local air quality concerns close to airports include reducing delay and improving operational efficiency of mobile sources (BAA, 2007; GAL, 2009; AEA, 2009). Various opportunities exist for alternative fuels to be used at airports (e.g., buildings, aircraft, and ground vehicles in airport controlled areas). However, many of the main sources of airport- related PM2.5 emissions (and the primary potential users of alternative fuels) are not under the direct control of airport operators in terms of the emission sources. These include airport-related access roadways and their associated road vehicles, ground support equipment (GSE) (which, in the ACRP 02-23 project, are defined as vehicles and equipment used on the airfield that support aircraft operations that are often controlled by airlines, other fixed base operators, as well as airports) and aircraft. Many airports around the country are developing emission reduction plans identifying actions that can be undertaken to reduce airport-related emissions. Airport operators can assist their tenants by generally supporting the development of infrastructure and supply for alternative fuel at and near the airport. The focus of the ACRP 02-23 project was to identify the possible benefits of various alternative fuels use on improving local air quality. Airports operators can also work with other key stakeholders, such as local governments, to further facilitate the implementation of alternative fuels. These actions will result in the more widespread use of alternative fuel and, therefore, a greater reduction in PM2.5 emissions can be achieved than by the airport acting alone.