Maricopa County Air Quality Department 1001 North Central Ave. Phoenix, Arizona 85004 Maricopa County Air Quality Department Protecting and improving our.

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Maricopa CountyAir Quality Department1001 North Central Ave.Phoenix, Arizona 85004

Maricopa County Air Quality Maricopa County Air Quality DepartmentDepartment

Protecting and improving our most basic resourceProtecting and improving our most basic resource

Barbara RoachNon-Title V Permit Engineer

Maricopa Quality Air Quality Department

(602) 372-3060Email: [email protected]

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Protecting and improving our most basic resourceProtecting and improving our most basic resourceCollocated Rock Products Plants

• Interim modeling procedure for two or more “collocated sources”

• Procedure does not include “clustered sources”

• “Clustered sources” operate independently but are located in close proximity to each other

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Definition of Source

• “Any building, structure, facility, or installation that may cause or contribute to air pollution.” [Rule 100 § 200]

• All pollution-emitting equipment that belong to same industrial grouping, located on contiguous or adjacent property, and under common control are considered one source.

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Protecting and improving our most basic resourceProtecting and improving our most basic resourceDefinition of Collocation

Collocated sources will meet the following criteria:• Operate under common control

– site management with decision making authority over operations

– contract for service

– a support/dependency relationship (over 50% of production)

– same owner

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Protecting and improving our most basic resourceProtecting and improving our most basic resourceDefinition of Collocation

• Are located on contiguous or adjacent property

• Have the same major Industrial Grouping (SIC code)

– Support activities are part of the same industrialgrouping even if they have two different SICcodes (e.g. sand & gravel mining, SIC code 14and asphalt production, SIC code 29)

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Todd MartinNon-Title V Permit Engineer

Maricopa Quality Air Quality Department

(602) 506-7248Email: [email protected]

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Protecting and improving our most basic resourceProtecting and improving our most basic resourceDispersion Modeling

• Permittee shall conduct a dispersion model analysis for PM-10

• Purpose: Determine whether source will contribute to a violation of any National Ambient Air Quality Standard (NAAQS):– Annual PM-10 standard = 50 µg/m3

– 24 hour PM-10 standard = 150 µg/m3

• Modeling:– Is performed on the air emissions from the entire

facility– Covers releases occurring during normal business

operation; it does not cover catastrophic or accidental releases

– Takes background concentrations into consideration, to understand possible cumulative effects

Planning and Development

The modeling should be done for all criteria pollutants as applicable, i.e. CO, NOx, SOx, VOC. A hot mix asphalt plant would require this type of modeling.

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Protecting and improving our most basic resourceProtecting and improving our most basic resourceModeling Process

• A screen model may be run to determine the maximum off site concentration

• Incorporate background concentrations from nearest Maricopa County monitoring station– Background = Annual average– Available on MCAQD web site (Air Monitoring)

• If the modeled concentrations are greater than the NAAQS, then more refined modeling may be performed (AERMOD)

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Protecting and improving our most basic resourceProtecting and improving our most basic resourceModeling Guidelines

• EPA Guideline on Air Quality Models (40 CFR Part 51 Appendix W, November 2005)

• ADEQ Air Dispersion Modeling Guidelines for Arizona Air Quality Permits (December 2004)

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Protecting and improving our most basic resourceProtecting and improving our most basic resourceAERMOD Modeling Process

• Submit a modeling protocol to the Department– Project background– Regional characteristics (model parameters)

• Geology• Metrology• Facility layout• Emission profiles for each source of PM-10• Stack parameters• Other modeling assumptions used

• MCAQD Approval of Protocol

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Protecting and improving our most basic resourceProtecting and improving our most basic resourceDispersion Model Analysis

• Ambient PM-10 impact is based on:1. Annual: The highest estimated annual

average concentration determined from annual averages of individual years;

2. 24-Hour: The highest, second-highest estimated concentration;

3. Add: The annual average PM-10 concentration from nearest monitoring station

4. Compare result with NAAQGS

• If model indicates an exceedance of NAAQGs, MCAQD reserves the right to deny the Permit Application

Maricopa County Air Quality Department 1001 North Central Ave. Phoenix, Arizona 85004 Maricopa County Air Quality Department Protecting and improving our.

Documents

air pollution

air emissions

basic resource

owner slide

collocated sources procedure

definition of source

major industrial grouping

dispersion modeling