Information you requested on NO 2: Regional Administrator (RA) Authority on 

monitoring

Lydia Wegman to: hking 12/18/2009 03:04 PM

Cc: weinstock.lewis, crabtree.tricia, Watkins.Nealson, jenkins.scott

Heidi, 

Here is the information you requested on the authority of Regional Administrators to require additional 

monitors. Please let us know if you have any more questions about this. 

Lydia

----- Forwarded by Lydia Wegman/RTP/USEPA/US on 12/18/2009 03:01 PM -----

From: Lewis Weinstock/RTP/USEPA/US

To: Lydia Wegman/RTP/USEPA/US@EPA

Cc: Bridgid Curry/DC/USEPA/US@EPA, Charlotte Bertrand/DC/USEPA/US@EPA, David 

Orlin/DC/USEPA/US@EPA, John Hannon/DC/USEPA/US@EPA, Karen 

Martin/RTP/USEPA/US@EPA, Nealson Watkins/RTP/USEPA/US@EPA, Richard 

Wayland/RTP/USEPA/US@EPA, Scott Jenkins/RTP/USEPA/US@EPA, 

Wayland.Richard@epamail.epa.gov, Padmini Singh/DC/USEPA/US@EPA

Date: 12/18/2009 01:12 PM

Subject: OMB requested information of NO2: Regional Administrator (RA) Authority on monitoring

Lydia:

Please forward to Heidi, as was requested during the morning call.

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The relevant language from the monitoring section (III) of the preamble is included in the attachment. 

This authority would be "bounded" by the need for state and/or regional office data analyses such as the 

evaluation of existing ambient data and/or emissions data, or through quantitative measures such air 

quality modeling, that indicate that an area might have ground-level NO2 concentrations that may exceed 

the NAAQS (in locations not already covered by minimum monitoring requirements). Quantitative

information would form the basis of the RA decision. Several examples of why this type of RA authority 

might be employed are included in the preamble. 

We note factors that might be considered by the RA in the evaluation of additional monitoring 

requirements including: (1) the variety in the amount or types of fleet mix in an area, (2) congestion 

patterns, (3) terrain, or (4) geographic areas within a CBSA. We also note that the decision would be 

documented in annual monitoring network plans that are updated annually by states and posted for the 

public.

Where else in current monitoring regulations can this type of authority be found? Several examples are 

documented in this message. Key passages are highlighted in yellow (hope it shows in your email 

system)

40 CFR Part 58, Appendix D - Network Design Criteria for Ambient Air Quality Monitoring

http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=16139e5d8e6819a456d374e25024f390&rgn=div9

&view=text&node=40:5.0.1.1.6.7.1.3.32&idno=40

4.1 Ozone (O3) Design Criteria. (a) State, and where appropriate, local agencies must operate O3

sites for various locations depending upon area size (in terms of population and geographic 
characteristics) and typical peak concentrations (expressed in percentages below, or near the O3

NAAQS). Specific SLAMS O3site minimum requirements are included in Table D–2 of this 

appendix. The NCore sites are expected to complement the O3

data collection that takes place at 

single-pollutant SLAMS sites, and both types of sites can be used to meet the network minimum 

requirements. The total number of O3

sites needed to support the basic monitoring objectives of

public data reporting, air quality mapping, compliance, and understanding O3-related

atmospheric processes will include more sites than these minimum numbers required in Table

D–2 of this appendix. The EPA Regional Administrator and the responsible State or local air

monitoring agency must work together to design and/or maintain the most appropriate O3network

to service the variety of data needs in an area.

(b) Within an O3

network, at least one O3site for each MSA, or CSA if multiple MSAs are 

involved, must be designed to record the maximum concentration for that particular metropolitan 

area. More than one maximum concentration site may be necessary in some areas. Table D–2 of

this appendix does not account for the full breadth of additional factors that would be considered

in designing a complete O3monitoring program for an area. Some of these additional factors 

include geographic size, population density, complexity of terrain and meteorology, adjacent O3

monitoring programs, air pollution transport from neighboring areas, and measured air quality in 

comparison to all forms of the O3NAAQS (i.e., 8-hour and 1-hour forms). Networks must be

designed to account for all of these area characteristics. Network designs must be re-examined in 

periodic network assessments. Deviations from the above O3requirements are allowed if

approved by the EPA Regional Administrator.

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4.5 Lead (Pb) Design Criteria. (a) State and, where appropriate, local agencies are required to 

conduct ambient air Pb monitoring taking into account Pb sources which are expected to or have 

been shown to contribute to a maximum Pb concentration in ambient air in excess of the 

NAAQS, the potential for population exposure, and logistics. At a minimum, there must be one 

source-oriented SLAMS site located to measure the maximum Pb concentration in ambient air 

resulting from each Pb source which emits 1.0 or more tons per year based on either the most 

recent National Emission Inventory ( http://www.epa.gov/ttn/chief/eiinformation.html ) or other 

scientifically justifiable methods and data (such as improved emissions factors or site-specific 

data) taking into account logistics and the potential for population exposure.

(i) One monitor may be used to meet the requirement in paragraph 4.5(a) for all sources involved 

when the location of the maximum Pb concentration due to one Pb source is expected to also be 

impacted by Pb emissions from a nearby source (or multiple sources). This monitor must be 

sited, taking into account logistics and the potential for population exposure, where the Pb 

concentration from all sources combined is expected to be at its maximum.

(ii) The Regional Administrator may waive the requirement in paragraph 4.5(a) for monitoring

near Pb sources if the State or, where appropriate, local agency can demonstrate the Pb source

will not contribute to a maximum Pb concentration in ambient air in excess of 50% of the
NAAQS (based on historical monitoring data, modeling, or other means). The waiver must be

renewed once every 5 years as part of the network assessment required under 58.10(d).

(b) State and, where appropriate, local agencies are required to conduct Pb monitoring in each 

CBSA with a population equal to or greater than 500,000 people as determined by the latest 

available census figures. At a minimum, there must be one non-source-oriented SLAMS site 

located to measure neighborhood scale Pb concentrations in urban areas impacted by 

re-entrained dust from roadways, closed industrial sources which previously were significant 

sources of Pb, hazardous waste sites, construction and demolition projects, or other fugitive dust 

sources of Pb.

(c) The EPA Regional Administrator may require additional monitoring beyond the minimum

monitoring requirements contained in 4.5(a) and 4.5(b) where the likelihood of Pb air quality

violations is significant or where the emissions density, topography, or population locations are

complex and varied.

Lewis Weinstock

Group Leader, Ambient Air Monitoring Group

U.S. EPA Office of Air Quality Planning and Standards

MD C304-06

Research Triangle Park, NC 27711

919-541-3661 919-541-1903 (Fax)