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| History Timeline Alternatives MIS/DEIS Bibliography | ||
5.8 AIR QUALITY5.8.1 REGULATORY SETTING AND METHODOLOGYAir Quality in southeastern Pennsylvania is under the regulatory jurisdiction of (PADEP and City of Philadelphia, Air Management Services.)The Federal Clean Air Act, last amended in 1990 (CAA) and National Ambient Air Quality Standards (NAAQS) establish pollutants considered harmful to public health and the environment. The CAA established two types of air quality standards: (1) Primary and (2) Secondary. "Primary standards" set limits to protect public health, while allowing for an adequate margin of safety. These standards consider sensitive populations such as asthmatics, children, and the elderly. "Secondary standards" set limits to protect public welfare from known or anticipated adverse effects. These standards protect animals, crops, vegetation, buildings and manmade materials, aesthetics, visibility, or other economic values from damages or losses. The EPA set NAAQS for the following six principal pollutants, which are called "criteria" pollutants.
State Implementation Plan (SIP) and Conformity - In 1972, EPA approved Pennsylvania's original State Implementation Plan (SIP). To implement the CAA, states are required to adopt a SIP that sets forth fundamental strategies to implement, maintain, and enforce the NAAQS in air quality control basins and regions. SIPs form the blueprint to achieve air quality goals within a state, including items such as emission limitations on stationary and mobile sources. All federally approved or financially assisted actions must conform to SIPs. Section 176 of CAA requires that all activities supported or funded by the federal government be in conformity with the relevant SIP. For purposes of this requirement, "conformity" means: "...conforming to the purpose of eliminating or reducing the severity and number of NAAQS violations, and achieving expeditious attainment of those standards..." "...not (i) causing or contributing to any new violation of any standard; (ii) increasing the frequency or severity of any existing violation; or (iii) delaying timely attainment of any standard..." Under Section 176 (c) of the CAA, MPOs may approve a transportation project only if it is demonstrated that estimated project emissions do not cause conforming transportation plans and programs to aggregately exceed the emission reduction projections and schedules assigned in the SIP. DVRPC acts as the duly designated MPO for the nine-county Philadelphia, Camden, and Trenton area. DVRPC updates the Philadelphia region's Transportation Improvement Program (TIP) and the Long Range Plan (LRP). The Schuylkill Valley Metro project was included in the 1997-2000 TIP. The Reading Area Transportation Study is the MPO in Berks County. The Berks County Planning Commission updates the TIP/LRP in the Reading metropolitan area. Conformity determinations, in all cases, must consider the latest planning assumptions and emissions model, and be rendered in accordance with the consultation requirements of the regulations. With its emphasis on the transportation plan, conformity forces a long-term focus and an examination of land use and growth assumptions. Conformity determinations for TIPs must always be examined in the context of the plan and its 20-year time frame to ensure that future attainment deadlines are met. The following criteria were used to evaluate the significance of ambient air impacts associated with project alternatives and any mitigation measures proposed:
A microscale analysis reviews the localized impacts to air quality from mobile vehicular sources. A microscale analysis generally investigates CO, which is a localized effect from traffic congestion. A mesoscale analysis reviews the regional impacts to air quality from mobile vehicular sources. A mesoscale analysis generally investigates VOCs and NOx, which are precursors to O3 formation, which is a regional effect from mobile vehicular and stationary sources. The EPA's MOBILE 5a H emission factor program was used to estimate pollutant emissions per vehicle mile traveled for the No-Build, TSM and Build Alternatives during the forecast year (2020). To determine the change in greenhouse emissions between the alternatives, energy consumption forecasts (measured in Btu) were used to estimate carbon dioxide emissions. The Federal Transit Administration's "New Starts Criteria" documents the development of Btu conversion factors for various fuels and electricity. Various air models have been used to assess past projects involving microscale predictions. Recently, PennDOT has developed an air quality screening model for use at intersections. The program was developed to satisfy the requirements of the National Environmental Policy Act. EPA Region III has approved use of the InterAir Model in its region, which includes Pennsylvania. After reviewing the regulatory requirements and screening methodologies adopted by other states, PennDOT developed a procedure using the same predictive models in an automated fashion. The model generalizes about certain features, but it allows the user to control critical input characteristics. The analyses focused on rush hour periods due to increases in arriving and departing traffic near the selected transit stations. Background levels of CO were assumed to be 2 ppm, for suburban areas and 3 ppm for urban areas. The "worst case" air quality impacts resulting from the modeling analyses were predicted for the project area. For the Transit Build Alternatives, the potential for short-term increases in air emissions during construction was reviewed. Mitigating measures for these short-term increases were identified. 5.8.2 AFFECTED ENVIRONMENTAir quality data from a total of 31 PADEP monitoring stations located in Berks, Chester, and Montgomery counties and the network of air quality monitoring stations maintained by Philadelphia Air Management Services were obtained. The ambient air monitoring stations sample for various particulate and gaseous pollutants. Particulates include total suspended matter, sulfates, lead, nitrates, and PM10 (respirable particulate matter that is less than 10 microns in diameter). Gaseous pollutants include sulfur dioxide, ozone, nitrogen dioxide, nitrogen oxides, and carbon monoxide. The existing ambient air quality and EPA's designation of the study corridor as attainment or nonattainment for the primary air pollutants was investigated.Nonattainment areas have sampled levels of pollutants that exceed the appropriate standards. The degree of nonattainment status (e.g., moderate, severe, or extreme) indicates the extent of exceedances in concentration and the time span available to achieve compliance. The U.S. Environmental Protection Agency (EPA) and PADEP designated the metropolitan Philadelphia-Wilmington-Trenton area as a severe nonattainment area for ozone. In Pennsylvania, the area includes Bucks, Chester, Delaware, Montgomery, and Philadelphia counties. In March 1996, EPA redesignated Philadelphia County as attainment and "maintenance" area for carbon monoxide. In May 1997, EPA redesignated the Reading area, which includes Berks County, as an attainment and "maintenance" area for ozone. Both air quality regions are in attainment for all other primary criteria air pollutants. 5.8.3 ENVIRONMENTAL CONSEQUENCES (IMPACTS)TSM (Microscale)For the TSM Alternative, a microscale analysis was performed for the surrounding intersections at five selected park-and-ride areas during peak traffic in 2020.
Build Alternatives (Microscale - New Stations) For the build alternatives, a microscale analysis was performed for the surrounding intersections at new transit stations during peak traffic in 2020.
Build Alternatives (Microscale - Existing Stations) For the build alternatives, a microscale analysis was performed for the surrounding intersections at existing transit stations during peak traffic during 2020.
Mesoscale and Greenhouse Gas Analysis Table 5.8-1 summarizes the results of the mesoscale analysis and greenhouse gas analysis for the build alternatives as compared to the No-Build and TSM Alternatives during 2020. Alternatives 1E, 5E, 5ET, and 6 offer reductions in all of the criteria pollutants and precursor air emissions in 2020. Use of the SVM rail service will reduce fuel consumption by automobiles and thus reduce automobile emissions of CO, NOx, VOCs, and PM10 in the SVM corridor. Other than a decrease in CO emissions, use of diesel locomotives for Alternative 1D and 2D will cause an increase of NOx, VOCs, and PM10 emissions during 2020. 5.8.4 MITIGATIONSince air impacts associated with four of the six build alternatives will be beneficial (the exceptions are Alternatives 1D and 2D), compared to no action, mitigation will not be necessary. Higher energy usage corresponds to increased greenhouse gas production and degraded air. The results of the energy analysis were used to estimate the greenhouse gas production for the alternatives. Diesel-powered vehicles should be kept in good mechanical condition to further reduce emissions, if one of these alternatives is selected as the LPA.
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