Source: http://federal.elaws.us/fr/notice/81-fr-30224
Timestamp: 2019-12-14 00:23:54
Document Index: 489896892

Matched Legal Cases: ['art 58', 'art 2', 'art 58', 'art 58', 'art 58', 'ART 58', 'art 58', '§\u200958', '§\u200958', '§\u200958', '§\u200958', 'art 58', 'art 58']

81 FR 30224 2016-11507. Revision to the Near-Road NO2, Federal Register
Home » 2016 Issues » 81 FR (05/16/2016) » 81 FR 30224 2016-11507. Revision to the Near-Road NO2
81 FR 30224 2016-11507. Revision to the Near-Road NO2
The Environmental Protection Agency (EPA) is proposing to revise the minimum monitoring requirements for near-road nitrogen dioxide (NO 2) monitoring by removing the existing requirements for near-road NO 2 monitoring stations in Core Based Statistical Areas (CBSAs) having populations between 500,000 and 1,000,000 persons, that are due by January 1, 2017. Current near-road NO 2 monitoring data indicate air quality levels in the near-road environment are well below the National Ambient Air Quality Standards (NAAQS) for the oxides of nitrogen. In light of this information, and due to the relationship between population, traffic, and expected NO 2 concentrations in the near-road environment, it is anticipated that measured near-road NO 2 concentrations in relatively smaller CBSAs (e.g., CBSAs with populations less than 1,000,000 persons) would exhibit similar, and more likely, lower concentrations, than what is being measured in larger urban areas.
II. Proposed Revisions to Near-Road NO 2 Minimum Monitoring Requirements
Comments must be received on or before June 30, 2016.
Submit your comments, identified by Docket ID No. EPA-HQ-OAR-2015-0486, at http://www.regulations.gov. Follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from Regulations.gov. The EPA may publish any comment received to its public docket. Do not submit electronically any information you consider to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Multimedia submissions (audio, video, etc.) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents made outside of the primary submission (i.e., on the Web, Cloud, or other file sharing system). For additional submission methods, the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit http://www2.epa.gov/dockets/commenting-epa-dockets.
Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-2015-0486. The EPA's policy is that all comments received will be included in the public docket without change and may be made available online at http://www.regulations.gov, including any personal information provided, unless the comment includes information claimed to be CBI or other information whose disclosure is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through http://www.regulations.gov or email. The www.regulations.gov Web site is an “anonymous access” system, which means the EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an email comment directly to the EPA without going through http://www.regulations.gov, your email address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, the EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If the EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, the EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects or viruses. For additional information about the EPA's public docket, visit the EPA Docket Center homepage at http://www.epa.gov/epahome/dockets.htm.
Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some information is not publicly available, e.g., CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, will be publicly available only in hard copy. Publicly available docket materials are available either electronically at www.regulations.gov or in hard copy at the Air and Radiation Docket and Information Center, EPA/DC, EPA William J. Clinton (WJC) West Building, Room 3334, 1301 Constitution Ave. NW., Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744 and the telephone number for the Air and Radiation Docket and Information Center is (202) 566-1742.
This action applies to state, territorial, and local air quality management programs that are responsible for ambient air quality monitoring under 40 CFR part 58. Categories and entities potentially regulated by this action include:
B. What should I consider as I prepare my comments for the EPA? Back to Top
1. Submitting CBI. Do not submit this information to the EPA through http://www.regulations.gov or email. Clearly mark any of the information that you claim to be CBI. For CBI information in a disk or CD ROM that you mail to the EPA, mark the outside of the disk or CD ROM as CBI and then identify electronically within the disk or CD ROM the specific information that is claimed as CBI. In addition to one complete version of the comment that includes information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public docket. Information so marked will not be disclosed except in accordance with procedures set forth in 40 Code of Federal Regulations (CFR) part 2.
In addition to being available in the docket, an electronic copy of this proposed rule will also be available on the Worldwide Web (WWW) through the Technology Transfer Network (TTN). Following signature, a copy of this proposed rule will be posted on the TTN's policy and guidance page for newly proposed or promulgated rules at the following address: https://www3.epa.gov/ttnamti1/monregs.html. The TTN provides information and technology exchange in various areas of air pollution control. A redline/strikeout document comparing the proposed revisions to the appropriate sections of the current rules will be provided in the docket.
II. Proposed Revisions to the Near-Road NO 2 Minimum Monitoring Requirements
On February 9, 2010, the EPA promulgated minimum monitoring requirements for the ambient NO 2 monitoring network in support of the revised NO 2 NAAQS (75 FR 6474; February 9, 2010). The 2010 NO 2 NAAQS revision included a 1-hour standard with a 98th percentile form averaged over 3 years and a level of 100 parts per billion (ppb), reflecting the maximum allowable NO 2 concentration anywhere in an area, while retaining the annual standard of 53 ppb.
As part of the 2010 NO 2 NAAQS rulemaking, the EPA promulgated revisions to requirements for minimum numbers of ambient NO 2 monitors which included new monitoring near major roads in larger urban areas, requirements to characterize NO 2 concentrations representative of wider spatial scales in larger urban areas (area-wide monitors), and monitors intended to characterize NO 2 exposures of susceptible and vulnerable populations. Specifically, the requirements for these minimum monitoring requirements that were promulgated in 2010 were as follows:
(a) The first tier of the ambient NO 2 monitoring network required near-road monitoring. [1] The requirements included the placement of one near-road NO 2 monitoring station in each CBSA with a population of 500,000 or more persons to monitor a location of expected maximum hourly concentrations sited near a major road. An additional near-road NO 2 monitoring station was required at a second location of expected maximum hourly concentrations for any CBSA with a population of 2,500,000 or more persons, or in any CBSA with a population of 500,000 or more persons that has one or more roadway segments with 250,000 or greater Annual Average Daily Traffic (AADT) counts. Based upon 2010 census data and data maintained by the U.S. Department of Transportation Federal Highway Administration on the most heavily trafficked roads in the U.S. (http://www.fhwa.dot.gov/policyinformation/tables/02.cfm), approximately 126 near-road NO 2 sites were required within 103 CBSAs nationwide at the time of rule promulgation.
(b) The second tier of the NO 2 network required area-wide NO 2 monitoring, [2] where area-wide means that the monitor is representative of a spatial scale of representativeness of neighborhood scale (0.5 to 4 km in dimension) or larger, as defined in 40 CFR part 58, appendix D, section 1.2. Requirements included the placement of one monitoring station in each CBSA with a population of 1,000,000 or more persons to monitor a location of expected highest NO 2 concentrations representing the neighborhood or larger spatial scales. Based on 2010 census data, approximately 52 area-wide NO 2 sites were required within 52 CBSAs at the time of rule promulgation.
(c) The third tier of the NO 2 minimum monitoring requirements was for the characterization of NO 2 exposure for susceptible and vulnerable populations. [3] The EPA Regional Administrators, in collaboration with states, required a minimum of 40 additional NO 2 monitoring stations nationwide in any area, inside or outside of CBSAs, in addition to the minimum monitoring requirements for near-road and area-wide monitors with a primary focus on siting these monitors in locations with susceptible and vulnerable populations. Monitoring sites intended to satisfy these NO 2 minimum monitoring requirements were required to be submitted to the EPA for approval. Per 40 CFR 58.10 and 58.13, states were required to submit a plan to the EPA for establishing required area-wide NO 2 monitoring sites and those NO 2 monitoring sites intended to represent areas with susceptible and vulnerable populations by July 1, 2012, and ensure that the monitoring stations were operational by January 1, 2013. State and local air monitoring agencies fulfilled the requirements for area-wide monitors and those sites representing areas with susceptible and vulnerable populations on schedule.
The near-road component of the ambient NO 2 monitoring network was also originally required to be completely operational by January 1, 2013. However, in 2012, the EPA proposed (77 FR 64244; October 19, 2012) and then finalized in 2013 (78 FR 16184; March 14, 2013), through a public notice and comment rulemaking, to require that the near-road NO 2 monitoring stations be installed in three phases. The revised installation schedule allowed more time for states to establish the near-road NO 2 network on a schedule consistent with available resources. The revised installation schedule for the near-road NO 2 monitoring network was modified to reflect the following:
Phase 1: In CBSAs with a population of 1,000,000 or more persons, one near-road NO 2 monitor shall be reflected in the state Annual Monitoring Network Plan submitted July 1, 2013, and that monitor shall be operational by January 1, 2014.
Phase 2: In CBSAs where two near-road NO 2 monitors are required (either because the CBSA has a population of 2,500,000 or more persons, or has a population of 500,000 or more persons plus one or more roadway segments having AADT counts of 250,000 or more), the second near-road NO 2 monitor shall be reflected in the state Annual Monitoring Network Plan submitted July 1, 2014, and that monitor shall be operational by January 1, 2015.
Phase 3: In CBSAs with a population of at least 500,000 persons, but less than 1,000,000 persons, one near-road NO 2 monitor shall be reflected in the state Annual Monitoring Network Plan submitted July 1, 2016, and the monitor shall be operational by January 1, 2017.
As of April 2016, the EPA estimates that 65 near-road NO 2 monitors are in operation. Tracking of near-road site meta-data indicate that state and local air monitoring agencies have successfully installed these new monitors in the appropriate locations, collectively placing monitors adjacent to highly trafficked roads in their respective CBSAs. The latest available near-road NO 2 monitoring site meta-data can be found at http://www3.epa.gov/ttn/amtic/nearroad.html.
II. Proposed Revisions to Near-Road NO 2 Minimum Monitoring Requirements Back to Top
The EPA is proposing to revise the minimum monitoring requirements for near-road NO 2 monitoring by removing the existing requirement for near-road NO 2 monitoring stations in CBSAs having populations between 500,000 and 1,000,000 persons, also known as Phase 3 of the near-road NO 2 network. This revision is based on the following key technical points:
The Phase 1 and Phase 2 near-road sites that have been installed to date are located at maximum concentration locations consistent with the guidance in the Near-road NO 2 Monitoring Technical Assistance Document (http://www3.epa.gov/ttn/amtic/files/nearroad/NearRoadTAD.pdf) as demonstrated by a detailed examination of site meta-data.
The higher populated CBSAs that contain these near-road NO 2 sites have higher mobile source emissions and associated indicators, such as Vehicle Miles Traveled (VMTs).
Further information on each of the key points is provided below.
The “Near-road NO 2 Network and Data Analysis” docket memo (docket memo) provides a review and analysis of the characteristics of the existing near-road NO 2 monitoring network and the relationships between NO 2 emissions, population, traffic, and NO 2 concentration data. [4] First, as noted above, the existing near-road NO 2 monitoring sites appropriately characterize the peak NO 2 concentrations that exist in the near-road environment within their respective CBSAs based on a detailed analysis of site metadata. This is an important assertion, as having the whole of the near-road NO 2 network be representative of expected peak, near-road NO 2 concentration in a given CBSA allows for an equitable comparison of near-road data across CBSAs that have near-road monitors. Monitoring agencies have provided a detailed accounting of total traffic volume and fleet mix while also accounting for the available information on congestion patterns, roadway design, terrain, and meteorology that went into their site selection. For example, it is estimated that 55 percent of the near-road sites are adjacent to one of the top five highest trafficked road segments in their respective CBSA, 71 percent are adjacent to one of the top 10 most highly trafficked roads, and 91 percent are adjacent to one of the top 25 most highly trafficked roads. Further, while all sites are within the required distance of 50 meters from their respective target road, state and local air agencies were successful in placing the sites in close proximity to roadway travel lanes. The EPA estimates that 59 percent of the sites are within 20 meters from their respective target road (which was a recommended target distance in the “Near-road NO 2 Monitoring Technical Assistance Document”), 87 percent are within 30 meters, and 96 percent are within 40 meters. Accordingly, the near-road monitoring network is situated to provide measurements that are a good representation of peak near-road NO 2 concentrations that exist in a given CBSA.
Second, higher populated CBSAs have correspondingly more vehicles and vehicle miles traveled, which in turn increases the availability of mobile source emissions that lead to increased opportunity for higher NO 2 concentrations, particularly in the near-road environment. This is evident upon evaluation of national VMT data available from the U.S. Department of Transportation in the State Transportation Statistics 2015 document. [5] A more specific evaluation of VMT by CBSA shows a clear, positive relationship between CBSA population size and VMT. Further, more densely populated CBSAs typically have more individual roads with relatively high traffic volumes than less densely populated CBSA counterparts. Based on this relationship, the EPA notes that higher populated areas correspondingly have more vehicles, which increase the mobile source derived emissions that lead to increased opportunity for higher NO 2 concentrations particularly in the near-road environment. [6]
Third, the analysis of the available near-road NO 2 data from sites having largely complete data in 2013 and 2014, and the 1st, 2nd, and 3rd quarters of 2015, indicate that while the larger CBSAs tend to have higher measured near-road NO 2 concentrations than lesser populated CBSAs, all readings are well below the applicable NO 2 NAAQS levels. This is true for both the annual and 1-hour NO 2 NAAQS, although this correspondence is stronger in the longer term averages of the data (such as the annual mean) compared to the peak 1-hour values for a given time frame.
Due to the phased implementation of the near-road NO 2 network, the initiation of valid data collection varies significantly by location. Accordingly, it is more straight-forward to analyze the data by the years when monitoring commenced, recognizing that the number of operating sites and the resulting data completeness will generally increase with time.
In 2013, four sites with sufficiently complete datasets (75 percent or greater annual completeness) were operational (Boise, ID; Des Moines, IA; Detroit, MI; and St. Louis, MO). Among these sites, the highest 98th percentile 1-hour daily max value was 50 ppb measured in the St. Louis CBSA. The highest annual mean value was 18 ppb measured in the Detroit CBSA.
In 2014, there were 21 CBSAs with near-road data meeting 75 percent completeness criteria. The highest 98th percentile 1-hour daily max value was 70 ppb measured in the Denver CBSA. The highest annual mean value was 27 ppb measured in the Los Angeles CBSA.
At the time of development of this proposal, 4th quarter 2015 data were not yet due to be submitted to the EPA. Using the 75 percent completeness criteria applied to the first three calendar quarters of submitted 2015 near-road NO 2 data, there were 42 CBSAs with data suitable for analysis. Of these data, the highest 98th percentile 1-hour daily max value was 72 ppb measured in the New York City CBSA. The highest annual mean value was 26 ppb measured in the Denver CBSA.
All of these data indicate that, to date, no near-road NO 2 site has collected data that are above or are threatening the annual NO 2 NAAQS of 53 ppb or the 100 ppb level of the 98th percentile 1-hour daily maximum value. As noted above, this is true for the larger CBSAs where the highest emissions and VMT exist.
In light of the information presented here and in the docket memo, the EPA is reconsidering the necessity of the third phase of the near-road NO 2 network. In particular, we have revisited the issue of whether the additional burden on state and local air monitoring agencies to operate Phase 3 of the near-road network is needed to provide evidence of compliance with the NO 2 NAAQS in the smaller CBSAs.
Given that measured near-road NO 2 concentrations to date are not approaching the NAAQS levels, even in the most heavily populated CBSAs with monitoring stations adjacent to the most heavily traveled road segments, we have concluded that the likelihood of measuring elevated NO 2 concentrations approaching or exceeding the NAAQS in smaller CBSAs is very small and, therefore, the Phase 3 requirement for near-road monitoring is no longer needed.
The EPA notes that even with the proposed deletion of the Phase 3 near-road requirements, the authority remains for the EPA Regional Administrator to work with states to install additional near-road NO 2 monitors above the minimum requirements (40 CFR part 58, section 4.3.4) in areas that may have concentrations approaching or exceeding the NAAQS. This authority provides a means for additional near-road NO 2 monitors to be installed in any area, such as a CBSA with a population below 1,000,000 persons, where data or other information suggest that near-road NO 2 monitoring might be warranted. Such an action could be based on research or non-regulatory data in an area, situations where an area has high background or area-wide NO 2 concentrations, a desired or needed understanding of near-road NO 2 concentrations and exposures, or in situations where an unusual or unique roadway related exposure to high ambient NO 2 concentrations exists such as an unusually highly trafficked road segment (i.e., a road segment having greater than 250,000 AADT counts) in a relatively smaller CBSA. The EPA views this existing Regional Administrator authority as a means to ensure that near-road NO 2 monitoring will continue to occur where needed, even after the proposed changes to minimum monitoring requirements.
In summary, given the relationships between population, traffic, and expected NO 2 concentrations in the near-road environment, the EPA anticipates that measured near-road NO 2 concentrations in relatively smaller CBSAs (e.g., CBSAs with populations less than 1,000,000 persons) would typically exhibit similar, if not lower, concentrations than what is being measured in larger urban areas. It has also been demonstrated that the available near-road NO 2 data indicate the air quality in the near-road environment is generally well below the NO 2 NAAQS across the network. Accordingly, the EPA is proposing to remove the requirement to install near-road NO 2 monitors in CBSAs having populations between 500,000 and 1,000,000 persons, also known as Phase 3 of the near-road NO 2 network, due by January 1, 2017. This proposed action would also relieve states from being required to document the need for Phase 3 requirements in their Annual Monitoring Network Plans that are due July 1, 2016.
The EPA also proposes to modify the requirement for a second near-road NO 2 monitor in any CBSA having 500,000 or more persons that also had one or more road segments with 250,000 or greater AADT counts to only apply to CBSAs having 1,000,000 or more persons. This is necessary to align all near-road NO 2 monitoring requirements language to only apply to those CBSAs having 1,000,000 persons or more. If there is a case of a relatively smaller CBSA having one or more road segments with 250,000 AADT counts or greater (of which the EPA is not aware), then the Regional Administrator's authority to require additional monitoring might be appropriate to consider and there could be an evaluation of whether monitoring is warranted.
This proposed revision is estimated to relieve requirements for approximately 53 near-road NO 2 monitors, based on 2014 Census Bureau population estimates (http://www.census.gov/population/metro/). This action would not modify the requirements for near-road NO 2 monitors in CBSAs having 1,000,000 or more persons and for a second near-road monitor in CBSAs having 2,500,000 or more persons, which collectively comprise what are also known as Phase 1 and Phase 2 of the near-road NO 2 network, respectively. This action also does not modify the existing requirements for area-wide NO 2 monitors or monitoring of NO 2 in areas with susceptible and vulnerable populations. The EPA requests comment on these proposed changes to the minimum monitoring requirements of near-road NO 2 monitors.
This action does not impose an information collection burden under the PRA. The proposed revisions do not add any information collection requirements beyond those imposed by the existing NO 2 monitoring requirements.
I certify that this action will not have a significant economic impact on a substantial number of small entities under the RFA. In making this determination, the impact of concern is any significant adverse economic impact on small entities. An agency may certify that a rule will not have a significant economic impact on a substantial number of small entities if the rule relieves regulatory burden, has no net burden or otherwise has a positive economic effect on the small entities subject to the rule. This action proposes to remove a sub-set of the current air monitoring requirements and, therefore, remove the requirement for the state and local air monitoring agencies to provide evidence of compliance with the NO 2 NAAQS in the near-road environment in CBSAs with less than 1,000,000 persons. We have, therefore, concluded that this action will relieve regulatory burden for all directly regulated small entities.
This action does not contain an unfunded mandate of $100 million or more as described in UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect small governments. This action imposes no enforceable duty on any state, local or tribal governments or the private sector. This action proposes to reduce the number of required near-road NO 2 monitors to be operated by state and local air monitoring agencies.
This action does not have federalism implications. It will not have substantial direct effects on the states, on the relationship between the national government and the states, or on the distribution of power and responsibilities among the various levels of government. In the spirit of Executive Order 13132, and consistent with the EPA policy to promote communications between the EPA and state and local governments, the EPA specifically solicits comment on this proposed rule from state and local officials.
This action does not have tribal implications, as specified in Executive Order 13175. This proposed rule imposes no requirements on tribal governments. Thus, Executive Order 13175 does not apply to this action. In the spirit of Executive order 13175, the EPA specifically solicits additional comment on this proposed action from tribal officials.
The EPA believes the human health or environmental risk addressed by this action will not have potential disproportionately high and adverse human health or environmental effects on minority, low-income or indigenous populations. The results of the network and data evaluation are contained in the Near-road NO 2 Network and Data Analysis docket memo, which provides a review and analysis of the characteristics of the existing near-road NO 2 monitoring network and the relationships between NO 2 emissions, population, traffic, and NO 2 concentration data. Further, this rule does not modify the existing requirements for near-road monitors required in CBSAs having 1,000,000 or more persons, area-wide NO 2 monitors, or monitoring of NO 2 in areas with susceptible and vulnerable populations.
For the reasons stated in the preamble, the Environmental Protection Agency proposes to amend 40 CFR part 58 as follows:
PART 58—AMBIENT AIR QUALITY SURVEILLANCE Back to Top
1.The authority citation for part 58 continues to read as follows:
2.Amend § 58.10 by revising paragraph (a)(5)(iv) and removing paragraph (a)(5)(v) to read as follows:
§ 58.10 Annual monitoring network plan and periodic network assessment.
(iv) A plan for establishing a second near-road NO 2 monitor in any CBSA with a population of 2,500,000 persons or more, or in any CBSA with a population of 1,000,000 or more persons that has one or more roadway segments with 250,000 or greater AADT counts, in accordance with the requirements of Appendix D, section 4.3.2 to this part, shall be submitted as part of the Annual Monitoring Network Plan to the EPA Regional Administrator by July 1, 2014. The plan shall provide for these required monitors to be operational by January 1, 2015.
3.Amend § 58.13 by revising paragraph (c)(4) and removing paragraph (c)(5) to read as follows:
§ 58.13 Monitoring network completion.
(4) January 1, 2015, for a second near-road NO 2 monitor in CBSAs that have a population of 2,500,000 or more persons or a second monitor in any CBSA with a population of 1,000,000 or more persons that has one or more roadway segments with 250,000 or greater AADT counts that is required in Appendix D, section 4.3.2 to this part.
Appendix D to Part 58—Network Design Criteria for Ambient Air Quality Monitoring Back to Top
4.3.2 Requirement for Near-Road NO 2 Monitors
(a) Within the NO 2 network, there must be one microscale near-road NO 2 monitoring station in each CBSA with a population of 1,000,000 or more persons to monitor a location of expected maximum hourly concentrations sited near a major road with high AADT counts as specified in paragraph 4.3.2(a)(1) of this appendix. An additional near-road NO 2 monitoring station is required for any CBSA with a population of 2,500,000 persons or more, or in any CBSA with a population of 1,000,000 or more persons that has one or more roadway segments with 250,000 or greater AADT counts to monitor a second location of expected maximum hourly concentrations. CBSA populations shall be based on the latest available census figures.
(1) The near-road NO 2 monitoring sites shall be selected by ranking all road segments within a CBSA by AADT and then identifying a location or locations adjacent to those highest ranked road segments, considering fleet mix, roadway design, congestion patterns, terrain, and meteorology, where maximum hourly NO 2 concentrations are expected to occur and siting criteria can be met in accordance with appendix E of this part. Where a state or local air monitoring agency identifies multiple acceptable candidate sites where maximum hourly NO 2 concentrations are expected to occur, the monitoring agency shall consider the potential for population exposure in the criteria utilized to select the final site location. Where one CBSA is required to have two near-road NO 2 monitoring stations, the sites shall be differentiated from each other by one or more of the following factors: Fleet mix; congestion patterns; terrain; geographic area within the CBSA; or different route, interstate, or freeway designation.
(b) Measurements at required near-road NO 2 monitor sites utilizing chemiluminescence FRMs must include at a minimum: NO, NO 2, and NO X.
[FR Doc. 2016-11507 Filed 5-13-16; 8:45 am]
4. Memo to docket located in Docket #EPA-HQ-OAR-2015-0486, document 1, under “Supporting Documents.”
5. http://www.rita.dot.gov/bts/sites/rita.dot.gov.bts/files/publications/state_transportation_statistics/state_transportation_statistics_2015/index.html.
6. Although the particular relationship between CBSA population size and any measured or expected near-road NO 2 concentrations is quite strong, the deviations from that expected relationship or trend are explainable. Near-road NO 2 measured concentrations are influenced by a number of known factors such as differences in traffic volumes, fleet mixes, congestion patterns, roadway design, terrain, and meteorology, along with some influence based upon the distance of the monitor to the road and with background NO 2 concentration differences. The influence of these factors is inherently part of the near-road NO 2 network (as referenced in 40 CFR part 58, section 4.3.2), and the measured concentrations at every near-road NO 2 site will always be influenced by any number of these factors to varying degrees in time.
30224-30229 (6 pages)
EPA-HQ-OAR-2015-0486, FRL-9946-34-OAR
2016-11507.pdf