UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION III

1650 Arch Street

Philadelphia, Pennsylvania 19103-2029

SUBJECT: Determination of Failure to Attain by 2005 and Determination of 

Attainment by 2008 for the 1-Hour Ozone National Ambient Air 

Quality Standards in the Baltimore Nonattainment Area in Maryland 

[EPA-R03-OAR-2011-0680]

FROM: Christopher Cripps, Project Officer /s/ January 26, 2012

Office of Air Program Planning

TO: File for Docket EPA-R03-OAR-2011-0680

THRU: Cristina Fernandez, Associate Director /s/

Office of Air Program Planning 

Throughout this document, “we,” “us,” and “our” refer to the Environmental Protection 

Agency (EPA).

I. For what Actions has this Document been prepared? 

EPA is proposing two separate and independent determinations for the Baltimore 1-hour 

severe ozone nonattainment area (hereafter “the Baltimore area”): 

A. Proposed Determination of Failure to Attain by Applicable Attainment Date:

For the Baltimore area, EPA is proposing to determine that the area did not attain the 1-

hour ozone NAAQS by the applicable attainment date, November 15, 2005. This proposed 

determination is based upon complete, quality-assured and certified air quality monitoring data for 

the 2003 through 2005 ozone seasons.

B. Proposed Determination of Current Attainment:

EPA is also proposing to determine that the Baltimore area is currently attaining the 1-hour 

ozone NAAQS, based upon complete, quality-assured and certified ambient air monitoring data 

showing the area has monitored attainment of the 1-hour ozone NAAQS for the most recent threeyear period 2008-2010. Preliminary data that is available for 2011 indicate that the Baltimore area 

continues to attain the standard. EPA’s review shows that the area has monitored attainment 

continuously since the 2006-2008 monitoring period. If this proposed determination is made final, 
2

the requirement for the State of Maryland to submit contingency measures related to attainment of 

the 1-hour ozone NAAQS in the Baltimore area shall be suspended. 

II. What is the Background for these Proposed Actions?

A. What are the Geographical Boundaries of the Baltimore Area?

The Baltimore area consists of Anne Arundel, Baltimore, Carroll, Harford, and Howard 

Counties and the City of Baltimore in Maryland.

B. What is the History of the Ozone Designations and Classifications for the Baltimore 1-

hour Ozone Nonattainment Area?

Pursuant to provisions of the CAA, EPA must establish NAAQS for certain widespread 

pollutants that cause or contribute to air pollution that is reasonably anticipated to endanger 

public health or welfare (sections 108 and 109 of the CAA). In 1979, EPA promulgated the 1-

hour ozone standard of 0.12 parts per million (ppm) (44 FR 8202, February 8, 1979). For ease of 

communication, EPA may informally report ozone concentrations in parts per billion (ppb) 

where one-thousand ppb equals one ppm. Thus, 0.12 ppm becomes 120 ppb or up to 124 ppb 

when rounding is considered. (Rounding is further discussed in section IV.B of this document.)

EPA first designated the Baltimore area as an ozone nonattainment area in 1978. See, 43 

FR 8962 at 9001, March 3, 1978.1 Under the 1990 Amendments to the CAA, the CAA 

designated “by operation of law” as nonattainment each area of the country that was already 

designated nonattainment for the 1-hour ozone NAAQS. The Baltimore area was one such preamendment ozone nonattainment area so designated nonattainment for ozone. The CAA as 

amended in 1990 further classified “by operation of law” each ozone nonattainment area as 

marginal, moderate, serious, severe, or extreme depending on the severity of the area's air quality 

problem. See, CAA sections 107(d)(1)(C) and 181(a). 

The control requirements and date by which attainment is to be achieved vary with an 

area's classification. Marginal areas are subject to the fewest mandated control requirements and 

had the earliest attainment date, November 15, 1993, while severe and extreme areas are subject 

to more stringent planning requirements and are provided more time to attain the standard. 

Based upon air quality monitoring data, the Baltimore area was classified as “severe-15” 

with a statutory attainment date of November 15, 2005. See, 56 FR 56694, November 6, 1991. 

C. What Is the Background of 1-Hour Ozone Anti-Backsliding Requirements in the 

Transition to the 1997 8-Hour Ozone Rule?

 

1 This action designated the Metropolitan Baltimore Intrastate Air Quality Control Region (See, 40 CFR 81.28), 

which has the same boundaries as the Baltimore 1-hour ozone nonattainment area, as nonattainment for 

“photochemical oxidants.” The term “photochemical oxidants” was replaced by “ozone” in a February 8, 1979 final 

rule (44 FR 8202 at 8220). 
3

On July 18, 1997 (62 FR 38856), EPA promulgated a new, more protective standard for 

ozone based on an 8-hour average concentration (the “1997 8-hour ozone NAAQS”). In an April 

30, 2004 final rule (69 FR 23858), EPA designated and classified most areas of the country 

under the 1997 8-hour ozone NAAQS promulgated in 40 CFR 50.10. We designated the 

Baltimore area as nonattainment for the 1997 8-hour ozone NAAQS. This 8-hour ozone 

nonattainment area is composed of the same five counties and city as the 1-hour ozone 

nonattainment area. We classified this area as moderate under the 1997 8-hour ozone NAAQS. 

At the time of designation, the same area remained in nonattainment for the 1-hour standard. 

On April 30, 2004 (69 FR 23951), EPA issued a final rule entitled “Final Rule To 

Implement the 8-Hour Ozone National Ambient Air Quality Standard — Phase 1” (the “Phase 1 

Implementation Rule”). Among other actions, this rule revoked the 1-hour ozone NAAQS in the 

Baltimore area (as well as in most other areas of the country), effective June 15, 2005. See, 40 

CFR 50.9(b); 69 FR 23951 at 23996; and 70 FR 44470, August 3, 2005.

Although EPA revoked the 1-hour ozone standard, eight-hour ozone nonattainment 

areas remain subject to certain 1-hour anti-backsliding requirements based on their 1-hour ozone 

classification. Initially, in our rules to address the transition from the 1-hour to the eight-hour 

ozone standard, EPA did not include contingency measures or the section 185 fee program 

among the measures retained as 1-hour ozone anti-backsliding requirements.2 However, on 

December 23, 2006, the United States Court of Appeals for the District of Columbia Circuit 

determined that EPA should not have excluded these requirements from its anti-backsliding 

requirements. South Coast Air Quality Management District v. EPA (SCAQMD v. EPA), 472 

F.3d 882 (D.C. Cir. 2006) rehearing denied 489 F.3d 1245 (clarifying that the vacatur was 

limited to the issues on which the court granted the petitions for review).

Thus, the Court vacated the provisions that excluded these requirements. As a result, 

States must continue to meet the obligations for 1-hour ozone NAAQS contingency measures 

and, for Severe and Extreme areas, major source fee programs. EPA has issued a proposed rule 

that would remove the vacated provisions of 40 CFR 51.905(e), and that addresses contingency 

measures for failure to attain or make reasonable further progress toward attainment of the 1-

hour standard. See 74 FR 2936, January 16, 2009 (proposed rule); 74 FR 7027, February 12, 

2009 (notice of public hearing and extension of comment period).

III. What is the Rationale for and Effect of these Proposed Determinations for the 

Baltimore Area?

A. What is the Rationale for the Proposed Determination of Failure to Attain by 

Applicable Attainment Date?

 

2

 Final Rule to Implement the 8-Hour Ozone National Ambient Air Quality Standard--Phase 1, 69 FR 23951 (April 

30, 2004).
4

After revocation of the 1-hour ozone standard, EPA must continue to provide a 

mechanism to give effect to the 1-hour anti-backsliding requirements. See, SCAQMD v. EPA, 47 

F.3d 882, at 903. In keeping with this responsibility with respect to 1-hour anti-backsliding 

contingency measures and section 185 fee programs, EPA proposes to determine that the 

Baltimore area failed to attain the 1-hour ozone standard by its applicable attainment date. 

Consistent with 40 CFR 51.905(e)(2) and the decision in SCAQMD v. EPA, upon revocation of 

the 1-hour ozone NAAQS for an area, EPA is no longer obligated to determine whether an area 

has attained the 1-hour NAAQS by its applicable deadline, except insofar as it relates to 

effectuating the anti-backsliding requirements that are specifically retained. EPA’s proposed 

determination here – that the area did not attain the 1-hour ozone standard by the November 15, 

2005 deadline (based on data for 2003-2005) is linked solely to two required 1-hour ozone antibacksliding measures: i.e., 1-hour contingency measures for failure to attain under section 

172(c)(9), and fee programs under sections 182(d)(3), 182(f) and 185. 

A final determination of failure to attain by the area’s 2005 1-hour ozone attainment date 

will not result in reclassification of the area under the revoked 1-hour standard. As a severe 1-

hour ozone nonattainment area, the Baltimore area is not subject to reclassification for the 1-hour

ozone standard, and in any event EPA is no longer required to reclassify any area to a higher 

classification for the 1-hour ozone NAAQS based upon a determination that the area failed to 

attain that NAAQS by its attainment date. See, 40 CFR 51.905(e)(2)(i)(B). 

EPA’s proposed determination that the area failed to attain the 1-hour ozone standard by 

its applicable date, if finalized, would bear on the area’s obligations with respect to two 1-hour

ozone anti-backsliding requirements whose implementation would be triggered by a finding of 

failure to attain by the applicable attainment date: section 172(c)(9) contingency measures for 

failure to attain, and sections 182(d)(3) ad 185 major stationary source fee programs. 

B. What is the Rationale for the Proposed Determination of Current Attainment and the 

Proposed Suspension of the Contingency Measures Related to Attainment of the 1-hour 

Ozone NAAQS?

Subpart 2 of part D of Title I of the CAA contains various air quality planning and SIP 

submission requirements for ozone nonattainment areas. We believe that one can reasonably 

interpret provisions regarding RFP and attainment demonstrations, along with certain other 

related provisions, so as not to require SIP submissions if an ozone nonattainment area subject to 

those requirements is monitoring attainment of the 1-hour ozone NAAQS as demonstrated with 

three years, of complete, quality-assured, air quality monitoring data. EPA has interpreted the 

general provision of subpart 1 of part D of Title I (sections 171 and 172) so as not to require the 

submission of SIP revisions concerning RFP, attainment demonstrations, or contingency 

measures. As explained in a memorandum dated May 10, 1995 from John S. Seitz, Director, 

Office of Air Quality Planning and Standards to the Regional Air Division Directors, entitled 

“Reasonable Further Progress, Attainment Demonstration, and Related Requirements for Ozone 

Nonattainment Areas Meeting the Ozone National Ambient Air Quality Standard,” (Clean Data 

Policy) EPA believes we can appropriately interpret the more specific RFP, attainment 

demonstration and related provisions of subpart 2 in the same manner. (See, Sierra Club v. EPA,
5

99 F.3d 1551 (10th Cir. 1996)). 

Under this policy, if EPA determines through rulemaking that the a 1-hour ozone 

nonattainment area is meeting the 1-hour ozone NAAQS, the requirements for a state to submit 

and have an approved SIP for the following nonattainment area plan elements can be suspended: 

(1) an attainment demonstration, and related components such as reasonably available control 

measures (RACM); (2) a RFP demonstration; and (3) contingency measures for failure to attain 

or to make reasonable further progress. 

These requirements would be suspended based on a finding of attainment of the 1-hour 

ozone NAAQS. 

The U.S. Court of Appeals for the District of Columbia Circuit upheld the provisions of 

40 CFR 51.918, which codified the Clean Data Policy. Previously Courts of Appeals for several 

other Circuits upheld the Clean Data Policy under the 1-hour standard. See NRDC v. EPA, 571 

F.3d 1245 (DC Cir. 2009); Sierra Club v. EPA, 99 F. 3d 1551 (10th Cir.1996); Sierra Club v. 

EPA, 375 F.3d 537(7th Cir. 2004) and Our Children’s Earth Foundation v. EPA, No. 04–73032 

(9thCir. June 28, 2005) (memorandum opinion). See the discussion and rulemakings cited in the 

Phase 2 Rule, 70 FR 71644-71646 (November 29, 2005).

C. What is the Status of the Maryland SIP Regarding the 1-Hour Ozone Anti-backsliding 

Requirement for Contingency Measures?

With respect to the 1-hour ozone anti-backsliding requirement for contingency measures, 

EPA has previously approved the State of Maryland’s 1-hour ozone attainment demonstration, 

RACM and RFP plans, and RFP contingency measures for Baltimore. See, 66 FR 49108 (Sept. 

26, 2001), 66 FR 54666 (Oct. 30, 2001), 68 FR 61103 (October 27, 2003), 68 FR 75191 

(December 30, 2003), 69 FR 7133 (February 13, 2004). See, also 64 FR 70397 (December 16, 

1999), 68 FR 40861 (July 9, 2003), 65 FR 4638 (July 28, 2000), 66 FR 36964 (July 16, 2001), 

and September 7, 2001 (66 FR 44760 (September 7, 2001) supplemental notices of proposed 

rulemakings for the October 30, 2001 final rule. 

While EPA did not approve contingency measures for failure to attain the 1-hour ozone 

NAAQS in the Baltimore area, reductions from measures that were not relied upon in the 

attainment demonstration provided more reductions than necessary to serve the purpose of 

contingency measures for this area. 

1. How Is the 2005 Contingency Requirement Calculated?

Contingency measures for failure to attain aims to provide for a 3 percent reduction in 

emissions. The amount of reductions required is computed from the same baseline as is used for 

computing reductions needed for reasonable further progress (RFP) (or as RFP was termed for 

the 1-hour ozone NAAQS, rate-of-progress (ROP)) for the attainment year. . See, “General 

Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990,” 57 FR 
6

13498 at 13511, April 16, 1992. In the case of the Baltimore area, this is 3 percent of its2005 

attainment year ROP; this equates to 8.23 tons per day (TPD) of volatile organic compounds 

(VOC) or 13.77 TPD of nitrogen oxides (NOx). This is computed as 3 percent of the “1990 

Inventory Adjusted to 2005.” How the “1990 Inventory Adjusted to 2005” is calculated as 

discussed in detail in section III.A and Tables 3 and 4 of the December 30, 2003 (68 FR 75191 at 

75192-75193), notice of proposed rulemaking (NPR) cited above. The 3 percent contingency 

requirement is calculated as follows:

Table 1 Summary of Contingency Requirement

Precursor VOC NOx

1990 Inventory Adjusted to 2005 (in TPD) * 274.43 458.86

Times 3 % (3/100) x 0.03 x 0.03

Minimum Contingency Requirement (in TPD) = 8.23 13.77

*From Tables 3 and 4 of the December 30, 2003 NPR (68 FR 75191 at 

75192-75193).

The determination of the “1990 Inventory Adjusted to 2005” is discussed in detail in the 

rulemaking notices associated with the approval of the 1-hour ozone NAAQS RFP plan for the 

Baltimore area. These notices are the December 30, 2003, notice of proposed rulemaking (68 FR 

75191) and the February 13, 2004, final rulemaking notice (69 FR 7133). These are appended as 

Appendix B to this document for the convenience of the reader. 

2. Does the Maryland SIP Provide for Additional reductions after 2005?

The approved 1-hour ozone RFP for the Baltimore area projected levels of VOC and 

NOx emissions of 221.53 and 344.47 TPD by November 15, 2005. See, Table 7 in the proposed 

rule (68 FR 75191 at 75194, December 30, 2003) for the February 13, 2004 (69 FR 7133) final 

action on the RFP plan for the 1-hour ozone NAAQS. This 1-hour ozone RFP plan set motor 

vehicle emissions budgets (MVEBs) of 55.5 TPD of VOC and 144.5 TPD of NOx. See, Table 2 

in the December 30, 2003 (68 FR 75191 at 75192) notice of proposed rulemaking. 

The approved RFP plan for the 1997 8-hour ozone NAAQS projected levels of VOC and 

NOx emissions as 219.25 and 277.50 TPD, respectively, by December 31, 2008. See, Table 5 in 

the proposed rule (75 FR 958 at 961, January 7, 2010) for the June 4, 2010 final action (75 FR 

31709) on the RFP plan for the 1997 8-hour ozone NAAQS. This plan set MVEBs of 41.2 TPD 

of VOC and 106.8 TPD of NOx. See, Table 10 in the January 7, 2010 (75 FR 958 at 963) notice 

of proposed rulemaking. Also appended for the convenience of the reader in Appendix B of this 

document are the rulemaking notices for the RFP plan for the Baltimore area under the 1997 8-

hour ozone NAAQS. These are the January 7, 2010, notice of proposed rulemaking (75 FR 958) 

and the June 4, 2010 final rulemaking notice (75 FR 31709).

An RFP/ROP includes a target level of emissions needed to meet the RFP requirement 

and a demonstration that the projected levels of emissions in the area by the RFP deadline date 

will be equal to or less than the target level after accounting for growth. See, 57 FR 13498 at 

13507-13508, April 16, 1992, and, for specifics relating to the Baltimore area, see the notices of 

proposed rulemaking cited in the preceding paragraph. While the baseline for the target levels 
7

for 2005 and 2008 are different, the projected levels of emissions are more comparable because 

they represent projections of actual emissions levels for some year in the future after the baseline 

year.3 Both the 2008 and 2005 use consistent methods for projecting growth in emissions-related 

activities after the baseline years and most importantly use the same emissions factor model, 

MOBILE6, for developing emissions factors for on-road or highway mobiles sources.

As a severe 1-our ozone nonattainment area the ROP plan included target levels of VOC 

and NOx emissions for November 15, 2005 which was the Baltimore area’s attainment date for 

the 1-hour ozone NAAQS. As a moderate 1997 8-hour ozone nonattainment area, the RFP plan 

for the Baltimore area included target levels of VOC and NOx emissions for December 31, 2008. 

EPA has approved the ROP and RFP plans for 2005 and 2008; see, 69 FR 7133, February 13, 

2004 and 75 FR 31709, June 4, 2010, respectively. 

The following table compares the projected emissions levels for November 15, 2005 and 

December 31, 2008:

Table 2 Comparison of the Projected Emissions Levels for November 15, 2005 and December 

31, 2008.

Portion of the Emissions Inventory All Emissions

On-Road Mobile 

Sources Only

Precursor VOC 

(TPD)

NOx 

(TPD)

VOC 

(TPD)

NOx 

(TPD)

RFP Projected Emissions as of 11/15/2005* 221.53 344.47 55.5 144.5

RFP Projected Emissions as of 12/31/2008 219.25 277.50 41.2 106.8

Difference 2.05 66.97 14.3 37.7

Notes on Sources: 

*Tables 2 and 7 in 68 FR 75191, December 30, 2003

**Tables 5 and in 75 FR 958, January 7, 2010.

The SIP for the Baltimore area provided for reductions in emissions from motor vehicles 

of 14.3 TPD of VOC and 37.7 TPD of NOx after November 15, 2005 but by December 31, 2008, 

and reductions in total emissions of 2.05 TPD of VOC and 66.97 TPD of NOx emissions after 

2005 but by December 31, 2008. The 1-hour attainment demonstration did not rely upon any of 

these reductions after November 15, 2005. As noted in section IIIC.1 of this document, the 

contingency measure requirement for failure to attain for the Baltimore area under the 1–hour 

ozone NAAQS was 8.23 TPD of VOC or 13.77 TPD of NOx. The Maryland SIP for the 

Baltimore area provided for over 65 TPD of NOx emission reductions after November 15, 2005 

but by December 31, 2008, of which a third would satisfy the contingency measure requirement. 

EPA can conclude that the Maryland SIP provided for sufficient emission reductions to fulfill the 

3 percent contingency requirement and has provided enough emission reductions after November 

15, 2005 to attain the 1-hour ozone NAAQS, as evidenced by attainment of the 1-hour ozone 

standard by 2008 and continued attainment thereafter.

 These additional reductions after 2005 helped bring the Baltimore area into attainment of the 1-

 

3 The baseline year for the 2005 ROP plan was 1990; the baseline year for the 2008 RFP plan was 2002. The 

baseline year emissions inventories are based on actual levels of emissions.
8

hour ozone NAAQS by 2008. 

D. What would be the Effects of these Proposed Determinations for the Baltimore Area?

As noted above, EPA is also proposing a separate and independent 1-hour ozone 

determination -- that the Baltimore area currently attains the 1-hour ozone standard, based on 

complete, quality-assured and certified ozone data for 2008-2010, and preliminary data available 

for 2011.4 If this determination is finalized, then even if EPA finalizes its proposed 

determination that the area failed to attain the 1-hour ozone standard by the 2005 deadline, it will 

not result in any 1-hour ozone contingency measure obligations for the area. Under EPA’s 

“Clean Data Policy” interpretation discussed in section III.B of this document, which was 

articulated first for the 1-hour standard and later codified for the 8-hour ozone standard (40 CFR 

51.918), a determination of attainment suspends obligations to make submissions for 

attainment-related requirements (including contingency measures) for that standard. See, for 

example, determination of 1-hour ozone attainment for Baton Rouge, 75 FR 6570 (February 10, 

2010). 

With respect to the 1-hour ozone anti-backsliding requirement for penalty fees, section 

182(d)(3) requires SIPs to include provisions required by section 185. Section 185 requires 1-

hour ozone SIPs for severe areas to provide that, if the area has failed to attain by the attainment 

date, each major stationary source of ozone precursors located in the area must begin paying a 

fee to the State. Thus a final determination of failure to attain by the area’s 1-hour attainment 

date would trigger the 1-hour anti-backsliding obligation to implement the penalty fee program 

under section 182(d)(3) 182(f) and 185, unless that obligation is terminated. 

IV. How Does EPA Compute Whether an Area Complies with the 1-Hour Ozone NAAQS?

A. What is the Level and Form of the 1-hour Ozone NAAQS?

The relevant regulation, 40 CFR 50.9(a), states the following regarding the 1-hour ozone 

NAAQS: 

(1) The level of the national 1-hour primary and secondary NAAQS for ozone is 0.12 

parts per million; and

(2) The 1-hour ozone NAAQS “is attained when the expected number of days per 

calendar year with maximum hourly average concentrations above 0.12 parts per million is equal 

to or less than 1, as determined by appendix H” to 40 CFR part 50.

We consider that a monitor exceeds the 1-hour ozone standard when that ambient air 

quality monitor records a 1-hour average ozone concentration above 0.12 ppm at least once in 

any given calendar day. Only the maximum 1-hour ozone concentration at the monitor during 

any calendar day is considered when determining if the 1-hour ozone NAAQS was exceeded on 

 

4 As noted elsewhere in this proposed determination, the monitoring data show that the Baltimore area has been 

attaining the 1-hour ozone standard continuously since 2008.
9

that day. That is, even when a monitor records more than one hourly concentration above 0.12 

ppm during a calendar day, that day counts as only a single “exceedance day.” 

See, 40 CFR 50.9 “National 1-hour primary and secondary ambient air quality standards for 

ozone” and “Interpretation of the 1-Hour Primary and Secondary National Ambient Air Quality 

Standards for Ozone” (40 CFR part 50, appendix H).

B. What are the Relevant Data Handling and Rounding Conventions for the 1-hour Ozone 

NAAQS? 

Although the 1-hour ozone NAAQS as promulgated in 40 CFR 50.9 does not address of 

specific data handling conventions, EPA’s publicly articulated position and the approach that the 

air quality management community has long universally adopted, is that the interpretation of the 

1-hour ozone standard requires rounding ambient air quality data consistent with the stated level 

of the standard, which is 0.12 ppm. 

As early as 1979, EPA’s guidance noted that the level as it is expressed in the standard 

defines the number of significant figures to be used in determining whether the standard was 

exceeded. The stated level of the standard is taken as defining the number of significant figures 

to be used in comparisons with the standard. For example, a standard level of 0.12 ppm means 

that measurements are to be rounded to two decimal places (0.005 rounds up), and, therefore, 

0.125 ppm is the smallest concentration value in excess of the level of the standard. See,

“Guideline for the Interpretation of Ozone Air Quality Standards,” EPA-450/4-79-003, OAQPS 

No. 1.2-108, January 1979. EPA has consistently applied the rounding convention in this 1979 

guideline. example, See, 68 FR 19106 at 19111, April 17, 2003; 68 FR 62041 at 62043, October 

31, 2003; and 69 FR 21717 at 21719, April 22, 2004. In the 1990 CAA Amendments, Congress 

expressly recognized the continuing validity of EPA guidance in the 1990 CAA Amendments. 

See, generally, H Comm. Rep. 101-490 pp. 197, 232 (1990) (House Energy and Commerce 

Committee Report).

A nonattainment area attains the 1-hour ozone NAAQS only when all monitors in that area attain 

the 1-hour ozone NAAQS. 

C. How is the Number of Expected Exceedance Days Determined, and, How is Attainment 

Determined under the Form of the 1-Hour Ozone NAAQS?

EPA determines if an area has attained the 1-hour ozone NAAQS by calculating, at each 

monitor, the average expected number of days over the standard per year (i.e., “average number 

of expected exceedance days”) during the applicable 3-year period. See, generally the General 

Preamble, 57 FR 13498 at 13506, April 16, 1992 and Memorandum from D. Kent Berry, Acting 

Director, Air Quality Management Division, EPA to Regional Air Office Directors; “Procedures 

for Processing Bump Ups and Extensions for Marginal Ozone Nonattainment Areas,” February 

3, 1994. 

A monitor shows attainment when the average number of “expected” number of 
10

“exceedance days” per calendar year “is less than or equal to one (1)” when averaged over a 

three-year period. . The level of the standard defines the number of significant figures to be 

used in comparisons with the standard which in this case means all averages are rounded to one 

significant figure. The smallest value which will exceed this standard is a value of 1.1, and, the 

average over a 3-year period is therefore rounded to one significant figure. Therefore, a 

violation occurs when the average number of expected exceedance days over a consecutive 3-

year period is greater than or equal to 1.1. Therefore, to not violate the 1-hour ozone NAAQS, 

the maximum aggregate sum of expected exceedance days over a consecutive 3-year period 

allowed is 3.1 because 3.1 divided by 3 is 1.03333, which when rounded to one significant figure 

is 1.0 which does not exceed 1. An aggregate sum of 3.2 expected exceedance days over a 

consecutive 3-year period do not meet this standard because 3.2 divided by 3 equals 1.0666, 

which when rounded to one significant figure is 1.1 and therefore is greater than 1.0. See, 40 

CFR part 50 appendix H and see, Memorandum from D. Kent Berry, Acting Director, Air 

Quality Management Division, EPA, to Regional Air Office Directors; “Procedures for

Processing Bump Ups and Extensions for Marginal Ozone Nonattainment Areas,” dated 

February 3, 1994. 

1. Estimating expected exceedance days from actual number of observed exceedances 

to account for missing data:

An observed daily maximum value at a monitor is considered to be valid if 75 percent of 

the hours from 9:01 a.m. to 9:00 p.m. were measured or if the highest hourly value measured is 

greater than the level of the standard. Where there are either no data for a day or data for less 

than the 75 percent of the hours between 9 a.m. and 9 p.m., a missing daily maximum ozone 

value may be assumed to be less than the level of the standard if the valid daily maxima on both 

the preceding day and the following day do not exceed 75 percent of the level of the standard. A 

day for which the daily maximum ozone value may be assumed to be less than 0.0125 ppm is 

termed “day assumed less than the standard.” See, appendix H to 40 CFR part 50. 

To account for missing data, the procedures in appendix H to 40 CFR part 50 are used to 

adjust the actual number of monitored exceedances of the standard in a year to yield the annual 

number of “expected exceedance days” (or “expected exceedance days”) at an air quality 

monitoring site. The following equation is used to convert the actual number of measured 

exceedances into an estimate of the annual number of “expected exceedance days:”

e = v + [ (v∕n) • (N-n-z)]

(The “•” symbol indicates multiplication, and, the “∕”symbol indicates division.)

where:

e = the estimated number of expected exceedance days for the year (denoted by “EST 

DAYS >/= .125” in the AQS reports),

N = the number of required monitoring days in the year,
11

n = the number of valid daily maxima,

v = the number of daily values above the level of the standard, denoted by “DAYS MAX 

>/= 0.125” in the AQS reports and

z = the number of days assumed to be less than the standard level, denoted by “MISSED 

DAYS < 0.125” in the AQS reports.

This estimated number of exceedance days, e, shall be rounded to one decimal place 

(fractional parts equal to 0.05 and higher round up). 

See, Appendix H to 40 CFR part 50.

The minimum required monitoring season for all parts of Maryland is 214 days from April 1st to 

October 31st of every year. See, 40 CFR 58.11(c) and Table D-3 “Ozone Monitoring Seasons by 

State” in appendix D to 40 CFR part 58. Therefore, the number of required monitoring days in 

the year, N, always equals 214.

2. Rounding of the number of expected exceedance days:

The computation of “expected exceedance days” is rounded to one significant figure 

for both the purposes of estimating the annual number of expected exceedance days at a monitor 

and for the annual average number of expected exceedance days over a 3-year period.

For example, for the 3-year average, any value less than 1.05 rounds down to 1.0, and, 

any value of 1.05 or greater rounds up to 1.1. Because a violation occurs when the average 

number of expected exceedance days over a consecutive 3-year period is greater than 1, a

violation occurs only when the average number of expected exceedance days over a consecutive 

3-year period is greater than 1.0. Therefore, to not violate the 1-hour ozone NAAQS, the 

maximum aggregate sum of expected exceedance days over a consecutive 3-year period allowed 

is 3.1 because 3.1 divided by 3 is 1.03333, which when rounded to one significant figure is 1.0 

which does not exceed 1. An aggregate sum of 3.2 expected exceedance days over a consecutive 

3-year period do not meet this standard because 3.2 divided by 3 equals 1.0666, which when 

rounded to one significant figure is 1.1 which is greater than 1.0. 

Example Calculation:

Suppose a monitor in Maryland had the following data for the 2006 ozone season:

the number of required monitoring days in the year, N, = 214

the number of valid daily maxima, n, = 211

the number of daily values above the level of the standard, v, = 2

the number of days assumed to be less than the standard level, z, = 1

Therefore, 
12

e = v + [ (v∕n) • (N-n-z)] = 2 + [(2/211) (214-211-1)] = 2.018,

which rounds to 2.0 estimated number of expected exceedance days for calendar year 

2006. 

Refer to Appendix A to this document for more details on the air quality data and 

examples of how the annual number of “expected exceedance days” was calculated from 

monitored data to account for missing days. Appendix A also contains the relevant air quality 

data reports downloaded from AQS. 

3. Source of air quality data:

A determination of whether an area's air quality meets the 1-hour ozone standard is

based upon three years of complete, quality-assured and certified air quality monitoring data 

gathered at established State and Local Air Monitoring Stations (``SLAMS'') in the 

nonattainment area and entered into the EPA's Air Quality System (AQS) database. Data from 

air monitors operated by state/local agencies in compliance with EPA monitoring requirements 

must be submitted to the AQS database. Monitoring agencies must annually certify that these 

data are accurate to the best of their knowledge, and, for calendar years 2010 and later, such 

certifications must be submitted by May 1st for the prior year’s data. See, 40 CFR 58.15. Thus, 

the certification of the air quality monitoring data for calendar year 2011 is due no later than 

May 1, 2012. Accordingly, EPA relies primarily on data in its AQS database when determining 

the attainment status of an area. See, 40 CFR 50.9; 40 CFR part 50, appendix H; 40 CFR part 

53; 40 CFR part 58, appendices A, C, D and E. All data are reviewed to determine the area's air 

quality status in accordance with 40 CFR part 50, appendix H.

V. What is EPA’s Analysis of the Data Regarding Baltimore’s Attainment of the 1-Hour

Ozone Standard?

A. What were the Monitors in the Baltimore Area during 2003 through 2010?

Table 3 summarizes the descriptive information for the ozone monitors in 

operation at any time during the 2003 to 2011 period. The “short name” will be used in 

subsequent tables to identify a monitor by name.

Table 3. Monitor Information Baltimore Area 2006-2010

Monitor (AQS ID 

No.)

Location Short name Years of operation 

(inclusive) 2003-

2011

24-510-0054 Furley E.S. Recreational Center, 

4633 Furley Avenue, Baltimore 

City

Furley 2006-2011

24-003-0014 Davidsonville Recreation Center, 

3801 Queen Anne Bridge Road, 

Davidsonville 2003-2011
13

Anne Arundel County

24-005-1007 Padonia Elementary School, 9834 

Greenside Drive, Cockeysville, 

Baltimore County

Padonia 2003-2011

24-005-3001 600 Dorsey Avenue, Essex, 

Baltimore County

Essex 2003-2011

24-013-0001 1300 W. Old Liberty Road, Carroll 

County

South Carroll 2003-2011

24-025-1001 Edgewood Chemical Biological 

Center (APG), Waehli Road, 

Edgewood, Harford County

Edgewood 2003-2011

24-025-9001 3560 Aldino Road, Harford County Aldino 2003-2011

24-003-0019 ‘Y’ Street, Fort Meade, Anne 

Arundel Co., MD

Fort Meade 2003-2004

24-510-0053 299 Ponca Street, Baltimore City, 

MD

Ponca Street 2003

Source: EPA AQS Database, “Quicklook Criteria Parameters,” Report Request ID 843146, 

Report Code AMP450, dated March 3, 2011, for the 2009 to 2010 data and Report Request ID 

937336, Report Code AMP450, dated December 13, 2011, for the 2011 data.

B. What is EPA’s Analysis of whether the Baltimore Area attained the 1-hour Ozone 

Standard by its 2005 Attainment Deadline? 

As noted previously, the applicable attainment date under the 1-hour ozone NAAQS for 

the Baltimore area was November 15, 2005. We base a determination regarding attainment of 

the 1-hour ozone NAAQS by this deadline on the average number of expected exceedance days

per year for the period 2003-2005.

During the entire 2003 to 2005 period, six ozone monitoring stations in the Baltimore 

area were in operation. Table 4 summarizes the ozone data collected at these six ozone 

monitoring stations during the 2003 to 2005 period and included in AQS for the Baltimore area. 

These data are complete and have been quality-assured and recorded in AQS. Maryland uses the 

AQS as the permanent database to maintain its data and quality assure the data transfers and 

content for accuracy. We have used the established rounding conventions set forth in our 

guidance documents and regulations. 

 

Table 4. Number and Average Number of Ozone Expected Exceedance Days 

and Design values per Year by Monitor in the Baltimore area 2003 to 2005

Monitor Information

Annual Number of 

Expected Exceedance

Days

Average Number 

of Expected 

Exceedance Days 

Per Year

Monitor (AQS ID No.) 2003 2004 2005 2003-05
14

Davidsonville Recreation Center, 

3801 Queen Anne Bridge Road, 

Anne Arundel County (24-003-

0014)

2.1 0.0 0.0 0.7

Padonia Elementary School, 

9834 Greenside Drive, 

Cockeysville, Baltimore County 

(24-005-1007)

0.0 0.0 0.0 0.0

600 Dorsey Avenue, Essex, 

Baltimore County (24-005-3001)

1.0 0.0 1.0 0.7

1300 W. Old Liberty Road, 

Carroll County (24-013-0001)

0.0 0.0 0.0 0.0

Edgewood Chemical Biological 

Center (APG), Waehli Road, 

Edgewood, Harford County (24-

025-1001)

1.0 1.0 2.0 1.3

3560 Aldino Road, Harford 

County (24-025-9001)

1.0 0.0 1.0 0.7

Source: EPA AQS Database, “Quicklook Criteria Parameters,” Report Request ID 843146, 

Report Code AMP450, dated March 3, 2011.

For the “Average number of expected exceedance days per year” column, two sample 

calculations follow:

For the “Essex” monitor: 

“Average number of expected exceedance days per year” = (1.0 + 0.0 + 1.0)/3 = 

0.67 = 0.7 rounded.

For the “Edgewood” Monitor:

“Average number of expected exceedance days per year” = (1.0 + 1.0 + 2.0)/3 = 

1.333 = 1.3 rounded.

As shown in Table 4 and the preceding sample calculation, the average number of 

expected exceedance days per year was greater than 1.0 at the “Edgewood” monitor 

(AQS ID# 24-025-1001). 

In addition to the six monitors listed in Table 4, two other monitors discontinued 

during the 2003-2005 period. These were the Fort Meade (ID# 24-003-0019) and the 

Ponca Street (ID# 24-510-0053) monitors. Because the “Edgewood” Monitor (AQS ID # 

24-025-1001) violated the ozone NAAQS in 2005 the data for these two monitors is not 

necessary to determine if the Baltimore area attained the 1-hour ozone NAAQS by 

November 15, 2005.
15

Therefore, based upon analysis of the air quality data, EPA can conclude the 

Baltimore area failed to attain the 1-hour ozone NAAQS by November 15, 2005, which 

was the applicable attainment date under the 1-hour ozone NAAQS for this 

nonattainment area.

C. Could an Extension of the Severe-15 Area Attainment Date been granted for the 

Baltimore Area?

Pursuant to section 181(a)(5) of the CAA, the state may request, and EPA may 

grant, up to two one-year attainment date extensions. EPA may grant an extension if 

both of two criteria are met. One of these criteria is: the area shall not measure more than 

one exceedance of the ozone standard at any monitoring site in the nonattainment area in 

the year in which attainment is required.

As shown in Table 4 (see section V.B of this document), the Edgewood, Harford 

County monitoring site recorded two (2) exceedances in 2005 which was the year in 

which attainment is required. Therefore, one criterion in section 181(a)(5) was not met, 

and, therefore, Baltimore area was not eligible for an attainment date extension under 

section 181(a)(5). 

D. What is EPA's Analysis of whether the Baltimore Area is currently attaining the 1-

Hour Ozone Standard?

During the entire period from 2006 through 2011, the same seven ozone monitoring 

stations in the Baltimore area were in operation. These are listed in Table 3 above. 

Table 5 summarizes the 1-hour ozone data collected at these six ozone monitoring 

stations during the 2006 to 2010 period and included in AQS for the Baltimore area. These data 

are complete and have been quality- assured, certified by the state and recorded in AQS. 

Maryland uses the AQS as the permanent database to maintain its data and to quality- assure the 

data transfers and content for accuracy. We have used the established rounding conventions set 

forth in our guidance documents and regulations. 

Table 5. Number and Average Number of Ozone Expected Exceedance Days per Year by 

Monitor in the Baltimore area 2006 to 2010

Monitor Information

Annual Number of Expected 

Exceedance Days

Average Number of 

Expected Exceedance Days 

Per Year

Monitor – AQS ID 

No. & “Short Name”

2006 2007 2008 2009 2010 2006-

2008

2007-

2009

2008-

2010

24-510-0054 – Furley 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

24-003-0014 –

Davidsonville 

0.0 1.0 0.0 0.0 0.0 0.3 0.3 0.0

24-005-1007 – 0.0 0.0 1.0 0.0 0.0 0.3 0.3 0.0
16

Padonia 

24-005-3001 – Essex 1.0 0.0 0.0 0.0 1.0 0.3 0.0 0.3

24-013-0001 – South 

Carroll 

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

24-025-1001 –

Edgewood 

2.0 1.0 0.0 1.0 1.1 1.0 0.7 0.7

24-025-9001– Aldino 1.0 2.0 0.0 0.0 0.0 1.0 0.7 0.0

Source: EPA AQS Database, “Quicklook Criteria Parameters,” Report Request ID 843146, 

Report Code AMP450, dated March 3, 2011.

Table 6 summarizes the 1-hour ozone data collected at these seven ozone monitoring 

stations during the 2009 to 2011 period and included in AQS for the Baltimore area. These data 

for 2009 and 2010 are complete and have been quality- assured, certified and recorded in AQS. 

The data for 2011 are those entered in AQS as of December 13, 2011. Data for at least 90 

percent of the 2011 monitoring season days has been entered into AQS but has not yet been 

certified by Maryland.

5

 The data shows that only one monitor recorded an exceedance of the 1-

hour ozone standard; the Edgewood site measured one exceedance of the 1-hour ozone standard 

during 2011. As of December 13, 20111, the 2011 data entered into AQS for the Edgewood site 

includes 209 days of valid data and also includes three days assumed less than the standard. 

Under the procedures discussed in Section IV “How Does EPA Compute Whether an Area 

Complies with the 1-Hour Ozone NAAQS?” elsewhere in this document, the number of expected 

exceedance days for the Edgewood site is only 1.0 for 2011. 

Table 6. Number and Average Number of Ozone Expected Exceedance Days per Year by 

Monitor in the Baltimore area 2009 to 2011

Monitor Information

Annual Number of Expected 

Exceedance Days

Average Number of 

Expected Exceedance Days 

Per Year 

Monitor – AQS ID No. & 

“Short Name”

2009 2010 2011 2009-2011

24-510-0054 – Furley 0.0 0.0 0.0 0.0

24-003-0014 – Davidsonville 0.0 0.0 0.0 0.0

24-005-1007 – Padonia 0.0 0.0 0.0 0.0

24-005-3001 – Essex 0.0 1.0 0.0 0.3

24-013-0001 – South Carroll 0.0 0.0 1.0 0.0

24-025-1001 – Edgewood 1.0 1.1 1.0 1.0

24-025-9001– Aldino 0.0 0.0 0.0 0.0

Source: EPA AQS Database, “Quicklook Criteria Parameters,” Report Request ID 843146, 

Report Code AMP450, dated March 3, 2011, for the 2009 to 2010 data and Report Request ID 

937336, Report Code AMP450, dated December 13, 2011, for the 2011 data.

As shown in Tables 5 and 6, no monitor in the Baltimore area had a value of the average 

number of expected exceedance days per year exceeding 1.0 in the three-year period 2006-2008. 

 

5 As noted in section IV.C.3 of this document, the deadline for certifying the 2011 data is May 1, 2012.
17

Furthermore, no monitor in the Baltimore area has had a value of the average number of 

expected exceedance days per year exceeding 1.0 in any three-year period after 2006-2008, that 

is, during the subsequent three-year periods 2007-2009 and 2008-2010. Thus the data show that 

the Baltimore area attained the 1-hour ozone standard in 2008 and has continued to attain this 

standard through 2010 based upon the most recent complete, quality-assured and certified data. 

Preliminary data available for 2011 indicate that the area continues in attainment for the 1-hour 

ozone standard for the period 2009 through 2011. 

Therefore, EPA can propose to find that the Baltimore area attained the 1-hour 

ozone NAAQS by November 15, 2008 and has remained in attainment through the end of 

2010 the last year for which quality assured data has been recorded in AQS and continues 

in attainment based upon the preliminary data available for 2011. 

VI. CONCLUSIONS AND RECOMMENDED AGENCY ACTION.

Therefore, I recommend that EPA propose the actions described in the two following 

paragraphs: 

A. Attainment by November 15, 2005:

Pursuant to EPA’s authority to ensure implementation of 1-hour ozone anti-backsliding 

requirements (CAA sections 301 and section 181(b)(2)) and based upon EPA's review of 

complete, quality-assured and certified ozone monitoring data for the three-year period 2003 to 

2005, EPA can propose to determine that the Baltimore severe 1-hour ozone nonattainment area 

failed to attain the 1-hour ozone NAAQS by the applicable attainment date of November 15, 

2005.

B. Clean Data Policy determination of attainment and contingency measures:

EPA can propose to determine that the Baltimore area is currently attaining the 1-hour 

ozone NAAQS, based upon the most recent three years of complete, quality-assured and certified 

ambient air monitoring data (2008-2010). The preliminary data that is available for 2011 show 

that the area continues to attain the standard. Moreover, the Baltimore area has monitored 

attainment of the 1-hour ozone NAAQS since the 2006-2008 monitoring period. If this proposed 

determination is made final, the obligation for the State of Maryland to submit contingency 

measures related to attainment of the 1-hour ozone NAAQS in the Baltimore severe 1-hour 

ozone nonattainment area would be suspended. These proposed determinations regarding the 1-

hour ozone standard, if finalized, would bear on the Baltimore area’s obligations with respect to 

the 1-hour ozone anti-backsliding requirements for section 172(c)(9) contingency measures for 

failure to attain that standard, and sections 182(d)(3) and 185 major stationary source fee 

programs.. 
18

List of EPA Guidance Memos and Documents

A. Guidance Memos and Documents

• “Guideline for the Interpretation of Ozone Air Quality Standards,” EPA-450/4-79-003, 

OAQPS No. 1.2-108, January 1979. 

• “General Preamble for the Implementation of Title I of the Clean Air Act 

Amendments of 1990,” 57 FR 13498, April 16, 1992.

• Memorandum from D. Kent Berry, Acting Director, Air Quality Management 

Division, EPA, to Regional Air Office Directors; “Procedures for Processing Bump 

Ups and Extensions for Marginal Ozone Nonattainment Areas,” dated February 3, 

1994.

• Memorandum from William G. Laxton, Director, Technical Support Division (MD14), entitled “Ozone and Carbon Monoxide Design Value Calculations,” dated June 

18, 1990.

List of Appendices

• Appendix A to Technical Support Document – Determination of Failure to Attain by 2005 

and Determination of Attainment by 2008 for the 1-Hour Ozone National Ambient Air Quality 

Standards in the Baltimore Nonattainment Area in Maryland [EPA-R03-OAR-2011-0680]

• Appendix B To: Determination of Failure to Attain by 2005 and Determination of 

Attainment by 2008 for the 1-Hour Ozone National Ambient Air Quality Standards in the 

Baltimore Nonattainment Area in Maryland [EPA-R03-OAR-2011-0680]
1

Appendix A to Technical Support Document – Determination of Failure to Attain by 2005 and Determination of Attainment 

by 2008 for the 1-Hour Ozone National Ambient Air Quality Standards in the Baltimore Nonattainment Area in Maryland

[EPA-R03-OAR-2011-0680]

In section 3 “Estimating the Number of Exceedances for a Year” of Appendix H to Part 50—“Interpretation of the 1-Hour Primary 

and Secondary National Ambient Air Quality Standards for Ozone,” a procedure is specified for determining when the expected 

number of days per calendar year with maximum hourly average concentrations above 0.12 ppm (235 μg/m3)

1

is equal to or less than

1. For purposes of clarity in the following discussion, it is convenient to use the term “exceedance” to describe a daily maximum

hourly average ozone measurement that is greater than the level of the standard. As discussed in section IV.B of the main body of this 

document, a measured value of 0.124 ppm rounds down to 0.12 ppm and does not constitute a monitored exceedance of the 0.12 ppm 

NAAQS. Values of 0.125 ppm and higher round up and do constitute a monitored exceedance of the 0.12 ppm NAAQS. 

The phrase “expected number of days with maximum hourly average ozone concentrations above the level of the standard” over a 3-

year period may be simply stated as the “average number of expected exceedance days” over a 3-year period. 

The basic principle in making this determination is relatively straightforward. Most of the complications that arise in determining the 

expected number of exceedance days per calendar year relate to accounting for incomplete sampling. In general, the average number 

of exceedance days per calendar year must be less than or equal to 1. In its simplest form, the number of exceedance days at a 

monitoring site would be recorded for each calendar year and then averaged over the past 3 calendar years to determine if this average 

is less than or equal to 1. 

EPA’s Interpretation of Expected Exceedance Days is as follows: The ozone standard states that the average number of expected 

number of exceedance days per year must be less than or equal to 1. The statistical term “expected number” is basically an arithmetic 

average. The following example explains what it would mean for an area to be in compliance with this type of standard. Suppose a 

monitoring station records a valid daily maximum hourly average ozone value for every day of the year during the past 3 years. At the 

end of each year, the number of days with maximum hourly concentrations above 0.12 ppm is determined and this number is averaged 

with the results of previous years. As long as this average remains “less than or equal to 1,” the area is in compliance.

In general, a valid daily maximum hourly average value may not be available for each day of the year, and it will be necessary to 

account for these missing values when estimating the number of exceedance days for a particular calendar year. The purpose of these 

computations is to determine if the expected number of exceedance days per year is less than or equal to 1. Thus, if a site has two or 

 

1

In the main body of this document the phrase “expected number of days per calendar year with maximum hourly average concentrations above 0.12 ppm (235 

μg/m3)” is termed “expected exceedance days per calendar year.” 
2

more observed exceedance days each year (or more than four over a three year period), the standard is not met and it is not necessary 

to use the procedures of Appendix H to account for incomplete sampling.

The term “missing value” is used here in the general sense to describe all days that do not have an associated ozone measurement. In 

some cases, a measurement might actually have been missed but in other cases no measurement may have been scheduled for that day. 

A daily maximum ozone value is defined to be the highest hourly ozone value recorded for the day. This daily maximum value is

considered to be valid if 75 percent of the hours from 9:01 a.m. to 9:00 p.m. were measured or if the highest hour is greater than the 

level of the standard.

In some areas, the seasonal pattern of ozone is so pronounced that entire months need not be sampled because it is extremely unlikely 

that the standard would be exceeded. Any such waiver of the ozone monitoring requirement would be handled under provisions of 40 

CFR, part 58. 

In the case of Maryland no monitoring is required under Table D-3 “Ozone Monitoring Season by State” to Appendix D of 40 CFR 

Part 58 for the period of November 1st through March 31st (inclusive). Therefore, the number of required monitoring days in the year

for these states is 214 (April 1st through October 31st inclusive).

Some allowance should also be made for days for which valid daily maximum hourly values were not obtained but which would quite 

likely have been below the standard. Such an allowance introduces a complication in that it becomes necessary to define under what 

conditions a missing value may be assumed to have been less than the level of the standard. The following criterion may be used for 

ozone: A missing daily maximum ozone value may be assumed to be less than the level of the standard if the valid daily maxima on 

both the preceding day and the following day do not exceed 75 percent of the level of the standard.

Let z denote the number of missing daily maximum values that may be assumed to be less than the standard. Then Appendix H 

requires that the following formula shall be used to estimate the expected number of exceedance days for the year:

e = v + [ (v∕n) • (N-n-z)]

(The “•” symbol indicates multiplication, and, the “∕”symbol indicates division.)

where:

e = the estimated number of exceedance days for the year (denoted by “EST DAYS >/= .125” in the AQS reports),
3

N = the number of required monitoring days in the year,

n = the number of valid daily maxima,

v = the number of daily values above the level of the standard, denoted by “DAYS MAX >/= 0.125” in the AQS reports and

z = the number of days assumed to be less than the standard level, denoted by “MISSED DAYS < 0.125” in the AQS reports.

This estimated number of exceedance days shall be rounded to one decimal place (fractional parts equal to 0.05 and higher round up).

Generally, after using the rounding convention, this formula yields a result that expected number of exceedance days at a monitor for a 

year is equal to the measured number when the number of valid daily maxima is close to the number of required monitoring days in 

the year. For a monitor required to monitor 214 days per year with one measured exceedance ( a daily maxima greater than 0.124 

ppm), the monitor needs at least 204 valid daily maxima (assuming “z,” the number of days assumed to be less than the standard level, 

is zero) to have the expected number of exceedance days remain less than 1.1. Using the formula for such a case, e = 1+ [ (1∕204) • 

(214-204-0)] = 1+10/204 = 1.049 which rounds down to 1.0. If the monitor measured two exceedances then the monitor needs at 

least 209 valid daily maxima (assuming z = zero the number of days assumed to be less than the standard level) to have the expected 

number of exceedance days remain less than 2.1. Using the formula for such a case, e = 2 + [ (1∕209) • (214-209-0)] = 2 +5/204 = 

2.047 which rounds down to 2.0. If the number of valid daily maxima was 208 then the formula would yield: e = 2 + [ (1∕208) • (214-

208-0)] = 2 +6/204 = 2.057 which rounds up to 2.1.

EPA’s AQS automatically performs these calculations when preparing certain reports such as the US EPA Air Quality System (AQS) 

Quick Look report (AMP450). 

Example calculations for selected monitors with the fewest number of valid daily maxima and with one or more recorded exceedances 

are provided below. A summary of the 1-hour ozone monitoring data for these monitors is presented in Table A-1. The data for these

monitors are in two reports titled “US EPA Air Quality System (AQS) Quick Look Criteria Parameters (AMP450)” dated March 3, 

2011 and December 13, 2011.

Table A-1 1-Hour Ozone Monitoring Data for Selected Monitors in the Baltimore Area and Years

Monitor Location (Nonattainment Area) AQS ID Year N n v z e

Davidsonville 24-003-0014 2003 214 205 2 1 2.1
4

Essex224-005-3001 2005 214 212 1 2 1.0

Essex 24-005-3001 2010 214 203 1 3 1.0

Edgewood 24-025-1001 2003 214 212 1 1 1.0

Edgewood 24-025-1001 2005 214 211 2 3 2.0

Edgewood 24-025-1001 2006 214 211 2 1 2.0

Edgewood 24-025-1001 2009 214 208 1 3 1.0

Edgewood 24-025-1001 2010 214 199 1 1 1.1

Edgewood 24-025-1001 2011 214 209 1 3 1.0

Aldino 24-025-9001 2007 214 209 2 3 2.0

Sources: EPA AQS Database, “Quicklook Criteria Parameters,” Report Request ID 843146, Report Code AMP450, dated 

March 3, 2011 (Copy Attached) for the 2003 through 2010 (inclusive) years.

EPA AQS Database, “Quicklook Criteria Parameters,” Report Request ID 937336, Report Code AMP450, dated December 13, 2011 

(Copy Attached) for the 2011 data.

Sample calculations follow:

For Davidsonville in 2003, e2003 = v + [ (v∕n) • (N-n-z)] = 1 + [(1∕205) • (214 – 205 – 1)] = 1 + [8/205] = 1.0399 which rounds to 1.0.

For Essex in 2005, e2005 = v + [ (v∕n) • (N-n-z)] = 1 + [(1∕212 • (214 – 212 – 2)] = 1 + [0/212] = 1.000 which rounds to 1.0.

For the Essex site in 2010, e2010 = v + [ (v∕n) • (N-n-z)] = 1 + [(1∕203 • (214 – 203 – 3)] = 1 + [8/203] = 1.0394 which rounds to 1.0.

For the Edgewood site in 2003, e2003 = v + [ (v∕n) • (N-n-z)] = 1 + [(1∕212 • (214 – 212 – 1)] = 1 + [1/212] 

 = 1.0047 which rounds to 1.0.

 

2

 Also would apply to the Carroll County monitor (AQS ID# 24-013-0001) for the year 2005, and, the Edgewood monitor (AQS ID# 24-025-1001) for the year 

2007.
5

For the Edgewood site in 2005, e2005 = v + [ (v∕n) • (N-n-z)] = 2 + [(2∕211 • (214 – 211 – 3)] = 2 + [0/211] 

 = 2.000 which rounds to 2.0.

For the Edgewood site in 2006, e2006 = v + [ (v∕n) • (N-n-z)] = 2 + [(2∕211 • (214 – 211 – 1)] = 2 + [4/211] 

 = 2.019 which rounds to 2.0.

For the Edgewood site in 2009, e2009 = v + [ (v∕n) • (N-n-z)] = 1 + [(1∕208 • (214 – 208 – 3)] = 1 + [3/208] 

 = 1.014 which rounds to 1.0.

For the Edgewood site in 2010, e2010 = v + [ (v∕n) • (N-n-z)] = 1 + [(1∕199 • (214 – 199 – 1)] = 1 + [14/199] 

 = 1.070 which rounds to 1.1.

For the Edgewood site in 2011, e2011 = v + [ (v∕n) • (N-n-z)] = 1 + [(1∕209 • (214 – 209 – 3)] = 1 + [2/209] 

 = 1.0096 which rounds to 1.0.

For the Aldino site in 2007, e20075 = v + [ (v∕n) • (N-n-z)] = 2 + [(2∕209 • (214 – 209 – 3)] = 1 + [4/209] = 2.019 which rounds to 2.0.

For any year where the observed number of daily values above the level of the standard is zero “e” is:

e = = v + [ (v∕n) • (N-n-z)] = 0 + [0/n] = 0.0000
Attachment to Appendix A to Technical Support Document – Determination of Failure to 

Attain by 2005 and Determination of Attainment by 2008 for the 1-Hour Ozone National 

Ambient Air Quality Standards in the Baltimore Nonattainment Area in Maryland [EPA-R03-

OAR-2011-0680]: 

EPA AQS Database, “Quicklook Criteria Parameters,” Report Request ID 843146, Report 

Code AMP450, dated March 3, 2011.

EPA AQS Database, “Quicklook Criteria Parameters,” Report Request ID 937336, Report 

Code AMP450, dated December 13, 2011, for the 2011 data.
(This Page Left Blank on Purpose)
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

QUICKLOOK CRITERIA PARAMETERS

Report Request ID: 843146 Report Code: AMP450 Mar. 3, 2011

Selection Criteria Page 1

User ID: AER

State County Site Parameter POC City AQCR UAR CBSA CSA

EPA

Region Method Duration Begin Date End Date

24

24

24

24

24

003

005

510

013

025

GEOGRAPHIC SELECTIONS

PROTOCOL SELECTIONS

Parameter

Classification Parameter Method Duration

QUICK LOOK 44201 1

SELECTED OPTIONS

MERGE PDF FILES

WORKFILE DELIMITER

EVENTS PROCESSING

Option Type Option Value

YES

,

EXCLUDE REGIONALLY CONCURRED EVENTS

SORT ORDER

1

2

3

4

5

6

7

Order Column

PARAMETER_CODE

STATE_CODE

COUNTY_CODE

SITE_ID

POC

DATES

EDT_ID

GLOBAL DATES

2003

Start Date End Date

2010

Tribal

APPLICABLE STANDARDS

Standard Description

Ozone 1-hour Daily 2005
Mar. 3, 2011

Note: The * indicates that the mean does

not satisfy summary criteria.

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

AIR QUALITY SYSTEM

QUICK LOOK REPORT (AMP450)

Page 1 of 9

EXCEPTIONAL DATA TYPES

EDT DESCRIPTION

0

1

2

5

NO EVENTS

EVENTS EXCLUDED

EVENTS INCLUDED

EVENTS WITH CONCURRENCE EXCLUDED
Mar. 3, 2011

Note: The * indicates that the mean does

not satisfy summary criteria.

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

AIR QUALITY SYSTEM

QUICK LOOK REPORT (AMP450)

Page 2 of 9

Ozone (44201) Maryland Parts per million (007)

SITE ID

P

O

C PQAO CITY COUNTY ADDRESS YEAR METH

VALID

DAYS

MEAS

1ST

MAX

1-HR CERT EDT

24-003-0014

24-003-0014

24-003-0014

24-003-0014

24-003-0014

24-003-0014

24-003-0014

1

1

1

1

1

1

1

1002

1002

1002

1002

1002

1002

1002

Not in a city

Not in a city

Not in a city

Not in a city

Not in a city

Not in a city

Not in a city

Anne Arundel

Anne Arundel

Anne Arundel

Anne Arundel

Anne Arundel

Anne Arundel

Anne Arundel

Davidsonville 

Recreation 

Center, 3801 

Queen Anne 

Bridge Road

Davidsonville 

Recreation 

Center, 3801 

Queen Anne 

Bridge Road

Davidsonville 

Recreation 

Center, 3801 

Queen Anne 

Bridge Road

Davidsonville 

Recreation 

Center, 3801 

Queen Anne 

Bridge Road

Davidsonville 

Recreation 

Center, 3801 

Queen Anne 

Bridge Road

Davidsonville 

Recreation 

Center, 3801 

Queen Anne 

Bridge Road

Davidsonville 

Recreation 

Center, 3801 

2003

2004

2005

2006

2007

2008

2009

019

047

047

047

047

047

047

205

203

208

212

212

208

207

.142

.109

.114

.124

.142

.098

.090

.132

.101

.112

.111

.111

.095

.089

Y

Y

Y

0

0

0

0

0

0

0

2ND

MAX

1-HR

1-HOUR 

NUM

DAYS

REQ

214

214

214

214

214

214

214

.103

.099

.112

.107

.110

.093

.083

3RD

MAX

1-HR

.102

.096

.110

.105

.104

.092

.080

4TH

MAX

1-HR

DAY

MAX>/=

0.125

2

0

0

0

1

0

0

EST

DAYS>/=

.125

 2.1

 0.0

 0.0

 0.0

 1.0

 0.0

 0.0

MISS

DAYS<

0.125

1

1

1

2

2

4

3
Mar. 3, 2011

Note: The * indicates that the mean does

not satisfy summary criteria.

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

AIR QUALITY SYSTEM

QUICK LOOK REPORT (AMP450)

Page 3 of 9

Ozone (44201) Maryland Parts per million (007)

SITE ID

P

O

C PQAO CITY COUNTY ADDRESS YEAR METH

VALID

DAYS

MEAS

1ST

MAX

1-HR CERT EDT

24-003-0014

24-003-0019

24-003-0019

24-005-1007

24-005-1007

24-005-1007

24-005-1007

24-005-1007

1

1

1

1

1

1

1

1

1002

1002

1002

1002

1002

1002

1002

1002

Not in a city

Fort Meade 

(U.S. Army)

Fort Meade 

(U.S. Army)

Cockeysville

Cockeysville

Cockeysville

Cockeysville

Cockeysville

Anne Arundel

Anne Arundel

Anne Arundel

Baltimore

Baltimore

Baltimore

Baltimore

Baltimore

Queen Anne 

Bridge Road

Davidsonville 

Recreation 

Center, 3801 

Queen Anne 

Bridge Road

9001 

'Y'STREET,FT.ME

ADE,ANNE 

ARUNDEL MD

9001 

'Y'STREET,FT.ME

ADE,ANNE 

ARUNDEL MD

Padonia 

Elementary 

School, 9834 

Greenside Drive

Padonia 

Elementary 

School, 9834 

Greenside Drive

Padonia 

Elementary 

School, 9834 

Greenside Drive

Padonia 

Elementary 

School, 9834 

Greenside Drive

Padonia 

Elementary 

2010

2003

2004

2003

2004

2005

2006

2007

047

019

019

047

047

047

047

047

207

208

212

214

214

208

213

214

.116

.128

.121

.110

.099

.114

.112

.093

.111

.118

.098

.103

.095

.106

.104

.088

Y

Y

Y

Y

Y

0

0

0

0

0

0

0

0

2ND

MAX

1-HR

1-HOUR 

NUM

DAYS

REQ

214

214

214

214

214

214

214

214

.109

.106

.098

.094

.093

.100

.100

.087

3RD

MAX

1-HR

.106

.104

.095

.091

.093

.093

.099

.087

4TH

MAX

1-HR

DAY

MAX>/=

0.125

0

1

0

0

0

0

0

0

EST

DAYS>/=

.125

 0.0

 1.0

 0.0

 0.0

 0.0

 0.0

 0.0

 0.0

MISS

DAYS<

0.125

1

1

0

0

0

0

1

0
Mar. 3, 2011

Note: The * indicates that the mean does

not satisfy summary criteria.

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

AIR QUALITY SYSTEM

QUICK LOOK REPORT (AMP450)

Page 4 of 9

Ozone (44201) Maryland Parts per million (007)

SITE ID

P

O

C PQAO CITY COUNTY ADDRESS YEAR METH

VALID

DAYS

MEAS

1ST

MAX

1-HR CERT EDT

24-005-1007

24-005-1007

24-005-1007

24-005-3001

24-005-3001

24-005-3001

24-005-3001

24-005-3001

24-005-3001

24-005-3001

24-005-3001

24-013-0001

24-013-0001

1

1

1

1

1

1

1

1

1

1

1

1

1

1002

1002

1002

1002

1002

1002

1002

1002

1002

1002

1002

1002

1002

Cockeysville

Cockeysville

Cockeysville

Essex

Essex

Essex

Essex

Essex

Essex

Essex

Essex

Not in a city

Not in a city

Baltimore

Baltimore

Baltimore

Baltimore

Baltimore

Baltimore

Baltimore

Baltimore

Baltimore

Baltimore

Baltimore

Carroll

Carroll

School, 9834 

Greenside Drive

Padonia 

Elementary 

School, 9834 

Greenside Drive

Padonia 

Elementary 

School, 9834 

Greenside Drive

Padonia 

Elementary 

School, 9834 

Greenside Drive

600 Dorsey 

Avenue

600 Dorsey 

Avenue

600 Dorsey 

Avenue

600 Dorsey 

Avenue

600 Dorsey 

Avenue

600 Dorsey 

Avenue

600 Dorsey 

Avenue

600 Dorsey 

Avenue

1300 W. Old 

Liberty Road

1300 W. Old 

2008

2009

2010

2003

2004

2005

2006

2007

2008

2009

2010

2003

2004

047

047

091

047

047

047

047

047

047

047

047

019

019

214

214

212

214

213

212

213

208

208

200

203

213

205

.129

.090

.110

.126

.117

.136

.137

.113

.117

.104

.128

.103

.115

.111

.085

.101

.109

.101

.109

.124

.103

.099

.099

.112

.099

.093

Y

Y

Y

Y

Y

0

0

0

0

0

0

0

0

5

0

0

0

0

2ND

MAX

1-HR

1-HOUR 

NUM

DAYS

REQ

214

214

214

214

214

214

214

214

214

214

214

214

214

.103

.084

.099

.095

.100

.104

.114

.101

.096

.090

.103

.095

.091

3RD

MAX

1-HR

.103

.083

.096

.094

.097

.101

.111

.100

.095

.085

.100

.088

.088

4TH

MAX

1-HR

DAY

MAX>/=

0.125

1

0

0

1

0

1

1

0

0

0

1

0

0

EST

DAYS>/=

.125

 1.0

 0.0

 0.0

 1.0

 0.0

 1.0

 1.0

 0.0

 0.0

 0.0

 1.0

 0.0

 0.0

MISS

DAYS<

0.125

0

0

2

0

1

2

1

4

5

3

3

1

3
Mar. 3, 2011

Note: The * indicates that the mean does

not satisfy summary criteria.

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

AIR QUALITY SYSTEM

QUICK LOOK REPORT (AMP450)

Page 5 of 9

Ozone (44201) Maryland Parts per million (007)

SITE ID

P

O

C PQAO CITY COUNTY ADDRESS YEAR METH

VALID

DAYS

MEAS

1ST

MAX

1-HR CERT EDT

24-013-0001

24-013-0001

24-013-0001

24-013-0001

24-013-0001

24-013-0001

24-025-1001

24-025-1001

24-025-1001

24-025-1001

1

1

1

1

1

1

1

1

1

1

1002

1002

1002

1002

1002

1002

1002

1002

1002

1002

Not in a city

Not in a city

Not in a city

Not in a city

Not in a city

Not in a city

Edgewood

Edgewood

Edgewood

Edgewood

Carroll

Carroll

Carroll

Carroll

Carroll

Carroll

Harford

Harford

Harford

Harford

Liberty Road

1300 W. Old 

Liberty Road

1300 W. Old 

Liberty Road

1300 W. Old 

Liberty Road

1300 W. Old 

Liberty Road

1300 W. Old 

Liberty Road

1300 W. Old 

Liberty Road

 Edgewood 

Chemical 

Biological 

Center (APG), 

Waehli Road

 Edgewood 

Chemical 

Biological 

Center (APG), 

Waehli Road

 Edgewood 

Chemical 

Biological 

Center (APG), 

Waehli Road

 Edgewood 

Chemical 

Biological 

Center (APG), 

Waehli Road

2005

2006

2007

2008

2009

2010

2003

2004

2005

2006

047

047

047

047

047

047

047

047

047

047

212

211

213

211

212

211

212

212

211

211

.111

.122

.120

.108

.088

.112

.153

.126

.133

.129

.106

.103

.119

.103

.083

.094

.119

.111

.130

.126

Y

Y

Y

Y

0

0

0

0

0

0

0

0

0

0

2ND

MAX

1-HR

1-HOUR 

NUM

DAYS

REQ

214

214

214

214

214

214

214

214

214

214

.104

.093

.115

.096

.076

.093

.115

.103

.122

.120

3RD

MAX

1-HR

.103

.092

.111

.089

.075

.091

.105

.103

.119

.109

4TH

MAX

1-HR

DAY

MAX>/=

0.125

0

0

0

0

0

0

1

1

2

2

EST

DAYS>/=

.125

 0.0

 0.0

 0.0

 0.0

 0.0

 0.0

 1.0

 1.0

 2.0

 2.0

MISS

DAYS<

0.125

2

0

1

3

2

1

1

0

3

1
Mar. 3, 2011

Note: The * indicates that the mean does

not satisfy summary criteria.

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

AIR QUALITY SYSTEM

QUICK LOOK REPORT (AMP450)

Page 6 of 9

Ozone (44201) Maryland Parts per million (007)

SITE ID

P

O

C PQAO CITY COUNTY ADDRESS YEAR METH

VALID

DAYS

MEAS

1ST

MAX

1-HR CERT EDT

24-025-1001

24-025-1001

24-025-1001

24-025-1001

24-025-9001

24-025-9001

24-025-9001

24-025-9001

24-025-9001

24-025-9001

24-025-9001

1

1

1

1

1

1

1

1

1

1

1

1002

1002

1002

1002

1002

1002

1002

1002

1002

1002

1002

Edgewood

Edgewood

Edgewood

Edgewood

Not in a city

Not in a city

Not in a city

Not in a city

Not in a city

Not in a city

Not in a city

Harford

Harford

Harford

Harford

Harford

Harford

Harford

Harford

Harford

Harford

Harford

 Edgewood 

Chemical 

Biological 

Center (APG), 

Waehli Road

 Edgewood 

Chemical 

Biological 

Center (APG), 

Waehli Road

 Edgewood 

Chemical 

Biological 

Center (APG), 

Waehli Road

 Edgewood 

Chemical 

Biological 

Center (APG), 

Waehli Road

3560 Aldino 

Road

3560 Aldino 

Road

3560 Aldino 

Road

3560 Aldino 

Road

3560 Aldino 

Road

3560 Aldino 

Road

3560 Aldino 

2007

2008

2009

2010

2003

2004

2005

2006

2007

2008

2009

047

047

047

091

019

019

047

047

047

047

047

212

202

208

199

214

213

213

214

209

212

213

.133

.115

.133

.129

.125

.117

.134

.127

.139

.118

.112

.121

.115

.123

.119

.118

.108

.121

.114

.132

.110

.091

Y

Y

Y

0

5

0

0

0

0

0

0

0

5

0

2ND

MAX

1-HR

1-HOUR 

NUM

DAYS

REQ

214

214

214

214

214

214

214

214

214

214

214

.111

.115

.119

.113

.101

.104

.112

.113

.119

.103

.090

3RD

MAX

1-HR

.108

.105

.098

.112

.098

.101

.108

.107

.117

.102

.086

4TH

MAX

1-HR

DAY

MAX>/=

0.125

1

0

1

1

1

0

1

1

2

0

0

EST

DAYS>/=

.125

 1.0

 0.0

 1.0

 1.1

 1.0

 0.0

 1.0

 1.0

 2.0

 0.0

 0.0

MISS

DAYS<

0.125

2

1

3

1

0

1

0

0

3

0

1
Mar. 3, 2011

Note: The * indicates that the mean does

not satisfy summary criteria.

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

AIR QUALITY SYSTEM

QUICK LOOK REPORT (AMP450)

Page 7 of 9

Ozone (44201) Maryland Parts per million (007)

SITE ID

P

O

C PQAO CITY COUNTY ADDRESS YEAR METH

VALID

DAYS

MEAS

1ST

MAX

1-HR CERT EDT

24-025-9001

24-510-0053

24-510-0054

24-510-0054

24-510-0054

24-510-0054

24-510-0054

1

1

1

1

1

1

1

1002

1002

1002

1002

1002

1002

1002

Not in a city

Not in a city

Baltimore

Baltimore

Baltimore

Baltimore

Baltimore

Harford

Baltimore (City)

Baltimore (City)

Baltimore (City)

Baltimore (City)

Baltimore (City)

Baltimore (City)

Road

3560 Aldino 

Road

299 PONCA 

STREET

Furley E.S. 

Recreational 

Center, 4633 

Furley Avenue.

Furley E.S. 

Recreational 

Center, 4633 

Furley Avenue.

Furley E.S. 

Recreational 

Center, 4633 

Furley Avenue.

Furley E.S. 

Recreational 

Center, 4633 

Furley Avenue.

Furley E.S. 

Recreational 

Center, 4633 

Furley Avenue.

2010

2003

2006

2007

2008

2009

2010

047

019

047

047

047

047

091

210

61

71

206

214

198

187

.103

.074

.100

.094

.098

.089

.118

.103

.064

.090

.090

.071

.082

.101

Y

0

0

0

0

0

0

0

2ND

MAX

1-HR

1-HOUR 

NUM

DAYS

REQ

214

214

214

214

214

214

214

.096

.060

.083

.089

.068

.080

.094

3RD

MAX

1-HR

.096

.060

.073

.084

.067

.079

.092

4TH

MAX

1-HR

DAY

MAX>/=

0.125

0

0

0

0

0

0

0

EST

DAYS>/=

.125

 0.0

 0.0

 0.0

 0.0

 0.0

 0.0

 0.0

MISS

DAYS<

0.125

2

0

0

0

0

0

4
Mar. 3, 2011

Note: The * indicates that the mean does

not satisfy summary criteria.

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

AIR QUALITY SYSTEM

QUICK LOOK REPORT (AMP450)

Page 8 of 9

44201

44201

44201

019

047

091

INSTRUMENTAL

INSTRUMENTAL

INSTRUMENTAL

ULTRA VIOLET

ULTRA VIOLET

ULTRAVIOLET RADIATION ABSORBTN

PARAMETER

METHOD

CODE COLLECTION METHOD ANALYSIS METHOD

METHODS USED IN THIS REPORT
Mar. 3, 2011

Note: The * indicates that the mean does

not satisfy summary criteria.

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

AIR QUALITY SYSTEM

QUICK LOOK REPORT (AMP450)

Page 9 of 9

PQAOS USED IN THIS REPORT

PQAO AGENCY DESCRIPTION

1002 State Of Maryland Air Management Administration
User ID: PFB QUICKLOOK CRITERIA PARAMETERS 

Report Request ID: 937336 Report Code: AMP450 

GEOGRAPHIC SELECTIONS 

Tribal 

Code State County Site Parameter POC City AQCR UAR CBSA CSA 

EPA 

Region 

24 510 0054 

24 003 0014 

24 005 1007 

24 005 3001 

24 013 0001 

24 025 1001 

24 025 9001 

PROTOCOL SELECTIONS 

Parameter 

Classification 

QUICK LOOK 

Parameter Method 

44201 

SELECTED OPTIONS 

Option Type 

EVENTS PROCESSING 

MERGE PDF FILES 

WORKFILE DELIMITER 

GLOBAL DATES 

Start Date End Date 

2011 2011 

Duration 

Option Value 

EXCLUDE REGIONALLY CONCURRED EVENTS 

YES 

1 

2 

3 

4 

5 

6 

7 

Selection Critetia Page 1 

Method Duration 

SORT ORDER 

Column 

PARAMETER_CODE 

STATE_CODE 

COUNTY_CODE 

SITE_ID 

POC 

DATES' 

Begin Date 

APPLICABLE STANDARDS 

Standard Description 

Ozone I-hour Daily 2005 

Ozone 8-Hour 2008 

Dec. 13, 2011 

End Date 
DESCRIPTION 

o NO EVENTS 

1 EVENTS EXCLUDED 

2 EVENTS INCLUDED 

AIR QUALITY SYSTEM 

QUICK LOOK REPORT (AMP450) 

EXCEPTIONAL DATA TYPES 

5 EVENTS WITH CONCURRENCE EXCLUDED 

Note: The * indicates that the mean does 

not satisfy summary criteria. Page 1 of 5 

Dec. 13, 2011 
Ozone (44201) 

I-HOUR 

P 

0 

SITE ID C PQAO CITY COUNTY 

24-003-0014 1 1002 Not in a city Anne Arundel 

24-005-1007 1 1002 Cockeysville Baltimore 

24-005-3001 1 1002 Essex Baltimore 

24-013-0001 1 1002 Not in a city Carroll 

24-025-1001 1 1002 Edgewood Harford 

24-025-9001 1 1002 Not in a city Harford 

24-510-0054 1 1002 Baltimore Baltimore 

Note: The * indicates that the mean does 

not satisfy summary criteria. 

,(City) 

AIR QUALITY SYSTEM 

QUICK,LOOK REPORT (AMP450) 

Maryland 

VALID 

DAYp 

ADDRESS YEAR METH MEAS 

Davidsonville 2011 047 208 

Recreation 

Center, 3801 

Queen Anne 

Bridge Road 

Padonia 2011 091 195 

Elementary 

School, 9834 

Greenside Drive 

600 Dorsey 2011 047 203 

Avenue 

noo w. Old 2011 047 2)0 

Liberty Road 

Edgewood 2011 091 209 

Chemical 

Biological 

Center (APG) , 

Waehli Road 

3560 Aldino 2011 047 201 

Road 

Furley E.S. 2011 091 203 

Recreational 

Center, 4633 

Furley Avenue. 

Page 2 of 5' 

Dec. 13, 2011 

Parts per million (007) 

NUM 1ST 2ND 3RD 4TH DAY EST MISS 

DAYS MAX MAX MAX MAX MAX> !lAYS> DAYS< 

REQ I-HR I-HR I-HR I-HR STD STD STD CERT EDT 

214 .111 .110 .102 .098 0 0.,0 1 0 

214 .113 .103 .103 .094 0 0.0 2 0 

214 .112 .109 .106 .103 0 0.0 6 0 

214 .099 .089 .085 .085 0 0.0 2 0 

214 .131 .121 .118 .118 1 1.0 3 0 

214 .114 .114 .113 .108 0 0.0 2 0 

214 .107 .106 .094 .092 0 0.0 1 0 
Ozone (44201) 

8-HOUR 

P 

0 

SITE ID C PQAO CITY COUNTY 

24-003-0014 1 1002 Not in a city Anne Arundel 

24-005-1007 1 1002 Cockeysville Baltimore 

24-005-3001 1 1002 Essex Baltimore 

24-013-0001 1 1002 Not in'a city Carroll 

24-025-1001 1 1002 Edgewood Harford 

24'-025-9001 1 1002 Not in a city Harford 

24-510-0054 1 1002 Baltimore Baltimore 

Note: The * indicates that the mean does 

not satisfy summary criteria. 

(City) 

AIR QUALITY SYSTEM 

QUICK LOOK REPORT (AMP450) 

Maryland 

ADDRESS YEAR METH %OBS 

Davidsonville 2011 047 96 

Recreation 

Center, 3801 

Queen Anne 

Bridge Road 

Padonia 2011 091 90 

Elementary 

School, 9834 

Greenside Drive 

600 Dorsey 2011 047 96 

Avenue 

1300 W. Old 2011 047 97 

Liberty Road 

Edgewood. 2011 091 96 

Chemical 

Biological 

Center (APG) , 

Waehli Road 

3560 Aldino 2011 047 93 

Road 

Furley E.S. 2011 091 95 

Recreational 

Center, 4633 

Furley Avenue. 

Page 3 of 5 

Dec. 13, 2011 

Parts per million ( 007) 

VALID NUM 1ST 2ND 3RD 4TH DAY 

DAYS DAYS MAX MAX MAX MAX MAX> 

MEAS REQ 8-HR 8-HR 8-HR 8-HR STD CERT EDT 

206 214 .094 .092 .088 .087 11 0 

193 214 .092 .088 .086 .086 9 0 

205 214 .101 .091 .087 .085 12 0 

208 214 .085 .080 .079 .079 5 0 

206 214 .114 .107 . 10 9 .098 17 0 

199 214 .098 .090 .088 .085 13 0 

203 214 .087 .084 .083 .082 7 0 
PARAMETER 

44201 

44201 

METHOD 

CODE 

047 

091 

Note: The * indicates that the mean does 

not satisfy summary criteria'. 

I 

AIR QUALITY SYSTEM 

QUICK LdoK REPORT (AMP450) 

I 

METHODS USED IN THIS REPORT 

COLLECTION METHOD 

INSTRUMENTAL 

INSTRUMENTAL 

Page 4 of 5 

Dec. 13, 2011 

ANALYSIS METHOD 

ULTRA VIOLET 

ULTRAVIOLET RADIATION ABSORBTN 
PQAO 

1002 

Note: The * indicates that the mean does 

not satisfy summary criteria. 

AIR QUALITY SYSTEM 

QUICK LOOK REPORT (AMP450) 

PQAO$ USED IN THIS REPORT 

AGENCY DESCRIPTION 

State Of Maryland Air Management Administration 

Page 5 of 5 

Dec. 13, 2011 
APPENDIX B To: Determination of Failure to Attain by 2005 and

Determination of Attainment by 2008 for the 1-Hour Ozone National

Ambient Air Quality Standards in the Baltimore Nonattainment Area in

Maryland [EPA-R03-OAR-2011-0680]

Appended in this appendix are copies of:

A December 30, 2003, notice of proposed rulemaking (68 FR 75191),

A February 13, 2004, final rulemaking notice (69 FR 7133),

A January 7, 2010, notice of proposed rulemaking (75 FR 958), and

A June 4, 2010, final rulemaking notice (75 FR 31709).
(This Page Left Blank on Purpose)