Toxicology Update -Implementation of
Revised Impacts Review Procedures
Mike Coldiron, P.E.Air Permits Division
Texas Commission on Environmental QualityAdvanced Air Permitting Seminar 2015
Revisions to Review
Procedures
Revisions toReview
Procedures
o Procedural changes to impacts review were designed to reduce processing times
o Fewer projects will need review by the Toxicology Division (TD)
o Fewer ESLs will need to be derived
Revisions to Review
Procedures
Revisions toReview
Procedures
o Case-by-case de minimis review will no longer require TD review
o For projects that meet the Tier II TD requirements, no TD review is needed
o Fewer particulate species will need a TD review
Revisions to Review
Procedures
Revisions toReview
Procedures
De Minimi
s
Toxicological
Tiered Review
s
Particulate
Matter
De Minimis Review
Procedures
Revisions to Review
Procedures
De Minimis
Revisions to Review
Procedures
De Minimi
s
De Minimis Review
ProceduresCase-by-case reviews no longer require TD approval and may be completed by the permit reviewer if:o Modeled emissions
rates are the rates without the use of emission controls;
o Impacts are evaluated using SCREEN3 only;
Revisions to Review
Procedures
De Minimi
s
De Minimis Review
Procedures
o The maximum off-property impacts are less than 10% of ESL for individual species; and
o The impacts for criteria pollutants are less than the SIL for all averaging periods
Current Toxicological Tiered Permit
Reviews
Revisions to Review
Procedures
Toxicological Tiered
Reviews
Current Toxicological Tiered Permit Reviews
Toxicology Review Tier
Review Criteria Responsibility for Review
Tier I All impacts are below ESLs APD
Tier IIImpacts on non-industrial receptors < ESL,Impacts on industrial receptors < 2X ESL
Toxicology
Tier III Case-by-case review Toxicology
Revised Toxicological Reviews Tier II
Toxicology Review Tier
Review Criteria Responsibility for Review
Tier I All impacts are below ESLs APD
Tier IIImpacts on non-industrial receptors < ESL,Impacts on industrial receptors < 2X ESL
APD
Tier III Case-by-case review Toxicology
Current Particulate Matter Review Procedures
Revisions to Review
Procedures
Particulate Matter
Revisions to Review
Procedures
Particulate
Matter
Current Particulate Matter Review Procedures
o Over 4,000 species on the ESL List, but many more species in the world
o TD receives frequent requests for ESLs for PM species
o An ESL must be developed for each species not on the current ESL List
Revisions to Review
Procedures
Particulate
Matter
Current Particulate Matter Review Procedures
o ESL development is time consuming, and applicants can wait two weeks or more for a response
o Many species are of limited concern
o Species of concern include metals and certain silica compounds
Revisions to Review
Procedures
Particulate
Matter
Revised Particulate Matter Review Procedures
o For species of limited concern, no additional review is required, as long as compliance with the PM2.5 NAAQS is demonstrated
o For species of concern, use the current review procedures
Revisions to Review
Procedures
Particulate
Matter
Particulate Matter Species of
Limited Concern
o Changes to PM species procedures represent a new impacts analysis approach
Revisions to Review
Procedures
Particulate
Matter
Justification for Revised Procedures
o New approach still protective of public health
o Comparison of 24-hour NAAQS standard to equivalent 1-hour concentration
Justification for Revised Procedures
Air Contaminant
Averaging Period
NAAQS (µg/m3)
1-hr to 24-hr Conversion
Factor
Equivalent 1-hr Concentration
(µg/m3)
PM2.5 24-hr 35 0.40 87.5
Justification for Revised Procedures
Air Contaminant
Averaging Period
Surrounding Land Use
Example Background
Concentration (µg/m3)
1-hr to 24-hr Conversion
Factor
Equivalent 1-hr
Concentration (µg/m3)
PM2.5 24-hr Industrial 25 0.40 62.5
PM2.5 24-hr Rural 18 0.40 45.0
Justification for Revised Procedures
Air Contaminant
Averaging Period
Equivalent 1-hr Concentration
(µg/m3)
Surrounding Land Use
Example Background
Concentration (µg/m3)
Equivalent 1-hr Allowable Total
Site Concentration
(µg/m3)
PM2.5 1-hr 87.5 Industrial 62.5 25.0
PM2.5 1-hr 87.5 Rural 45.0 42.5
Revisions to Review
Procedures
Particulate
Matter
Implementation of Revised PM
Review Procedures
o Identification of all species and species emission rate calculations are still required
o For species of limited concern, no further species-specific analysis is required
o An appropriate PM2.5 NAAQS analysis is required
Revisions to Review
Procedures
Particulate
Matter
Implementation of Revised PM
Review Procedures
o For all other species, the impacts analysis remains unchanged
o Even if the analysis is completed using the MERA flowchart, modeling may still be required to support the chemical flexibility condition
Permit Condition Revisions
Permit Condition Revisions
o Current chemical flexibility special condition requires an ESL for each species
o The special condition has been revised to accommodate the revised impacts analysis
o No exceedance of the PM2.5 NAAQS is allowed
Revised Procedure Exclusions
Revised Procedure Exclusions
o Contested case hearingso Public comments on
exposure to air contaminants
o Unsatisfactory compliance history rating
o Emissions of an APWL species in an APWL area
In Review
Summary
o Case-by-case de minimis review will no longer require TD review
o For projects that meet the Tier II TD requirements, no TD review is needed
In Review
Summary
o Fewer particulate species will need a TD review, and a PM2.5 NAAQS analysis will serve as a surrogate for these species
o The revised procedures are not allowed in certain cases
In Review
Websites
Home
Rules and Rulemaking
Index of Common Permitted Facilities
Effects Screening Levels
Tables
Forms
BACT
MERA
Air Dispersion Modeling
Contact Information
Phone Numbers
APIRT: (512) 239-3075
APD: (512) 239-1240 or
(512) 239-1250
Contact Information
Mike Coldiron Contact Information
Mike Coldiron, P.E.
(512) 239-5027