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PM2.5 CONFORMITY DETERMINATION for Baltimore Beltway I-695: MD 140 to MD 702

E. PM2.5 Hot Spot Analysis

As noted previously, EPA's final rule on PM2.5 hotspot analyses requires localized assessment for projects of air quality concern. The I-695 corridor project meets the criteria set forth in 40 CFR 93.123(b)(1) as amended for projects of air quality concern primarily because the project is an expanded highway project with a significant amount of truck traffic. Depending on location on I-695, the ADT is in excess of 250,000 with a truck percentage of between 10% and 11%. Although SHA traffic data shows no increase in peak hour volumes between No-build and Build conditions due to capacity restrictions and spreading of the peak over time, increasing the number of lanes could increase the ADT over a 24-hour period.

Construction-related emissions for the project were considered to be temporary since construction-related emissions will last less than five years at any one site, meeting the criterion of section 93.123(c)(5). Therefore, construction emissions are not required to be included in the hotspot analysis. EPA has not approved a PM2.5 SIP for Maryland, nor has EPA or the state air agency made any significance findings related to reentrained road dust for the Baltimore, MD PM2.5 nonattainment area. Therefore reentrained road dust is not considered in the analysis, per the Conformity Rule. In addition, as there is not an applicable PM2.5 SIP, there are no PM2.5 control measures and the project is in compliance with 40 CFR 93.117.

According to 40 CFR 93.123(b)(2) and (4), a quantitative analysis for applicable projects is not required until EPA releases modeling guidance in the Federal Register. However, a qualitative hot spot analysis is still required. For the I-695: MD 140 to MD702 project, a qualitative project-level hotspot assessment was conducted in order to assess whether the project will cause or contribute to any new localized PM2.5 violations, or increase the frequency or severity of any existing violations, or delay timely attainment of the PM2.5 NAAQS.

Existing Conditions

The affected areas for the purposes of this analysis are the portions of the Build Alternative that are not yet constructed or currently under construction. In general this area is from I-83 South (JFX-Exit 23) to Bel Air Road (US1-Exit 32). The following includes a discussion of currently available information on existing conditions related to air quality and traffic conditions in the project area.

Air Quality - Monitors

There are ten PM2.5 monitors in the Baltimore, MD PM2.5 nonattainment area: two in Baltimore County, six in Baltimore City, one in Anne Arundel County and one in Harford County. Based on 2006 air quality monitoring data, there is one monitor that exceeded the annual mean PM2.5 standard of 15.0 ug/m3. This monitor is located at 1900 East Patapsco Avenue in Baltimore City. No monitor in the PM2.5 nonattainment area exceeds the current 24-hour PM2.5 standard of 65 ug/m3. The monitor that exceeds the PM2.5 standards is located near the Port of Baltimore and does not match the site conditions of the I-695 Project. Appendix A provides a summary of the air quality monitoring data for 2005-2007.

There are two monitors that are in close proximity to the I-695 project. The impact area of Monitor #240051007, which is located in Cockeysville, MD adjacent to I-83 approximately two miles north of I-695, is similar to the traffic volumes, truck percents and terrain type to I-695 from I-83 South (JFX-Exit 23) to I-95 (Exit 33). The impact area of Monitor #240053001, which is located in Essex, MD adjacent to I-695 and MD702, is similar to the traffic volumes, truck percents and terrain type to I-695 from I-95 (Exit 33) to MD702 (Exit 36). A review of traffic data reveal that maximum ADT occurs in the area between I-83 South (JFX) and I-83 North (BHX). Therefore, this area will be the focus of the analysis. Refer to Table 1.

Transportation and Traffic Conditions

The Baltimore Beltway experiences congestion during the AM/PM peak hours due to capacity constraints and substandard geometric interchanges, which also create safety problems. Without improvements, the 2025 volumes on the I-695 corridor will exceed capacity during peak periods, causing a breakdown in the flow of traffic and a greater potential for accidents. The Baltimore Metropolitan Council (BMC) predicts that from 1990 to 2010 nearly 75 percent of all new commuter trips will be from a surburban site to a surburban site. These transportation trends and commuting patterns have created capacity and safety problems on the existing Beltway. A traffic volume comparison is shown on Table 1.

Table 1
Traffic Volume Comparison
Segment 1991
(FONSI Date)
2025 % Increase
West of MD 140 93,000 202,000 117%
West of I-83 (BHX) 134,000 257,250 92%
West of I-95 96,000 117,000 22%
West of MD 702 66,500 104,550 57%

Built and Natural Environment

The built and natural environment is consistent with the 1991 FONSI. Existing and future land use along the study portion of the I-695 corridor consists of a mixture of suburban-residential and employment-commercial.

Future Scenario

In the Baltimore Metropolitan Council (BMC) PM2.5 conformity assessment, regional emissions estimates of direct PM2.5 from on-road mobile sources show a continued decline through 2020, with slight increase level between 2020 and 2030. For the entire nonattainment area, direct on-road mobile sources PM2.5 annual emissions are expected to decrease by 47 percent in 2010 and by 61 percent in 2020 and 2030 from a 2002 baseline. The regional emissions estimates are shown on Table 2.

Table 2
Plan and TIP PM2.5 Conformity Mobile Source Emissions Results Network Based Analysis (tons/year) 4
Year Direct PM2.5 % Decrease from 2002 baseline Direct PM2.5
2002 1043.51 -
2010 551.02 47.19%
2020 406.33 61.06%
2030 411.58 60.56%

According to EPA, the 2007 Heavy-duty engine standards will result in the introduction of new, highly effective control technologies for heavy- duty engines. The new PM emissions standard for new heavy-duty engines of 0.01 grams per brake-horsepower-hour (g/bhp-hr) will take full effect for diesels in the 2007 model year. Particulate matter emission levels are expected to be 90 percent lower on a per vehicle basis than 2000 standards levels due to the 2007 diesel engine and fuel program. 5

Analytical Considerations

A comparison approach was used, in which the anticipated traffic volumes on roadways within the I-695 corridor project were compared to those on major roadways near existing air quality monitors. First, a list of monitoring stations within the BMC planning area was compiled. The list, presented in Appendix A, was reviewed in order to identify monitoring sites that are close to major roadways and exposed to similar traffic counts and truck percentages as the I-695 project.

As clarified in the preamble to the July 1, 2004 revision to the transportation conformity rule (64 FR 40056), the conformity rule requires that project-level analyses consider the year of expected peak emissions from the project. For PM2.5, this is expected to be a near- term year, such as the first year of operation of the project, because emission rates from vehicles are predicted to decline between the opening year (2010) and the last year of the area's transportation plan (2030) due in part to improvements in tailpipe emissions and national vehicle emissions control programs. As indicated in Table 2, the regional PM2.5 emissions are much higher in 2010 than in 2020 and 2030. Since regional emissions are a good indicator of the overall emissions trends in the region, it is expected that 2010 would be the year of peak emissions from the project and other emissions sources that affect the project area. While regional direct PM2.5 emissions do appear to increase slightly between 2020 and 2030, emissions are lower in 2020 and 2030 than in 2010. EPA projects that all jurisdictions in Maryland will meet the annual and 24-hour PM2.5 standards by 2015. Therefore, decreases in per vehicle emissions, coupled with other regional control programs both mobile and non-mobile, are expected to result in a continued decrease in emissions such that the year of opening (2010) is the most likely year of peak emissions. Some of these programs include a series of national vehicle control programs that are expected to reduce vehicle emissions substantially, such as the Tier II vehicle and fuel sulfur standards for light-duty vehicles, the 2007 Highway Rule for heavy-duty diesel vehicles, and other related programs.7

The study area will not be significantly influenced by the nonroad sources in the major metropolitan area of Baltimore, MD. In addition, there are several EPA programs in place or proposed that would tend to reduce current background PM2.5 levels from nonroad sources. These include Diesel Engine Retrofit Programs, the Clean Air Nonroad Diesel Emissions Rule, the Clear Skies Act, and the Interstate Air Quality Rule.

For this analysis traffic volumes on major roads within two miles of the monitor site were compared to traffic volumes within 2 miles of the analysis location. The selected analysis location is at the I-695/I-83 North (BHX) interchange. At this location, the total overall 2010 ADT volume would be 552,915 vehicles per day with a weighted truck percent of 9.128%, which would result in approximately 50,470 trucks. The selected monitor is east I-83 North (BHX), north of the I-695/I-83 North interchange. The analysis location and the selected monitor are affected by the similar traffic conditions. For the air quality monitor in this area (240051007) the total overall 2005 ADT volume within two miles is 449,850 vehicles per day with a weighted truck percent of 9.912%, which would result in approximately 44,590 trucks.

In comparing monitor site 240051007 to the analysis location, the 2010 traffic volumes for the analysis location are slightly higher than the 2005 traffic volumes for the monitor site with a slightly less weighted truck percentage. The total number of trucks at the affecting the analysis location would be 50,470 in 2010, which is slightly more than the trucks at the monitor site. The 2006 annual average PM2.5 concentration site 240051007 was 12.6 ug/m3 based on 116 readings, which is below the annual NAAQS for PM2.5 of 15.0 ug/m3. In 2006, the 98th percentile reading for the 24-hour PM2.5 concentration at this site was 32 ug/m3, which is well below the 24-hour NAAQS of 65 ug/m3.

Even though the number of trucks is higher at the analysis location than at the monitor site, this higher truck volume would not be expected to lead to a violation of the PM2.5 standards. First, as predicted by EPA and illustrated in the plan and TIP conformity analysis, emissions of PM2.5 from vehicles would be expected to decline between 2006 (the year of the monitoring data) and 2010 (the opening year of the road segments). Second, even assuming that all of the PM2.5 measured at the monitoring site originated only from trucks, the difference in truck traffic between the two locations (13%) would not be enough to create a violation, since the monitored values are well below the standard.

  Roadway ADT
Total ADTWeighted
I-83 156,025 - - 11 (2005)

I-695 218,350 - - 11
Seminary Ave. 12,175 - - 2
York Road: MD 45 37,150 - - 5
Dulaney Valley Rd: MD 146 26,150 - - 5
I-83 156,025 166,900 158,745 11 (2010)

I-695 218,350 257,250 228,075 11
Seminary Ave. 12,175 - 12,800 2
York Road: MD 45 37,150 - 39,050 5
Charles Street: MD 139 53,475 - 56,200 5
Falls Road: MD 25 29,075- 30,5605
Dulaney Valley Rd: MD 146 26,150- 27,4855

4 Data taken from: Conformity Determination of the 2004 Baltimore Regional Transportation Plan and FY 2007-2011 Transportation Improvement Program, Baltimore Metropolitan Council, August 2006.
5 Heavy-duty Engine and Vehicle Standards and Highway Diesel Fuel Sulfur Control Requirements - Final Rule ("2007 Heavy-Duty Highway Final Rule") (Signed December 21, 2000)
7 For more information on EPA's national vehicle control programs, please refer to EPA's Office of Transportation and Air Quality program information available at
8 2010 traffic data was estimated from 2005 and 2025 data. A 1% annual growth from the latest traffic counts was assumed for roadways for roads for which projected traffic volumes were not available. These are generally roads with smaller volumes which do not significantly impact results.
9 ibid
10 The truck percentage includes diesel and gasoline trucks. It also includes buses. SHA assumes that the truck percentages do not vary over time. 2% was assumed for local roads, 5% assumed for state highways.
Updated: 7/6/2011
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