Human Health Risk Assessment HHRA Program: OAQPSOAR Perspective

1
Human Health Risk Assessment (HHRA) Program
OAQPS/OAR Perspective

• Lydia Wegman, Director
• Health and Environmental Impacts Division
• Office of Air Quality Planning Standards
• November 14, 2007

2
HHRA Activities and Assessments Used by OAQPS
Background

• NCEA activities that provide essential support
  for OAR/OAQPS work
• Generation of the Integrated Science Assessment
  (ISA)
• Supports NAAQS standard setting
• Generation of IRIS assessments
• Supports Residual Risk standard setting
• Provision of expert advice on risk assessment
  methods, models, and approaches
• Supports OAQPS assessment and rulemaking efforts
  in both criteria and air toxics programs
• Supports mobile source air toxics rulemakings
  (OTAQ)
• NCEAs work critical to EPA for several reasons
• Ensures the integrity, credibility, and
  defensibility of rules and other work products
• Timely delivery of NCEA products central to
  Agencys ability to meet statutory requirements
  under the CAA

3
HHRA Activities and Assessments Used by OAQPS
NAAQS

• The Clean Air Act requires EPA to set National
  Ambient Air Quality Standards (NAAQS) for six
  pollutants to protect public health and welfare
  ozone, particulate matter, carbon monoxide, lead,
  nitrogen dioxide, sulfur dioxide
• EPA must review the scientific information and
  the standards for each pollutant every five years
• Partnership with NCEA critical to the NAAQS
  review process
• By analyzing and synthesizing the results of new
  studies, the Integrated Science Assessment (ISA)
  informs OAQPSs understanding and interpretation
  of the scientific evidence
• ISA also provides inputs into the quantitative
  risk and exposure assessments conducted by OAQPS
• ORD and OAR have been working together to improve
  the NAAQS review process meeting the 5-year
  deadlines requires close collaboration with NCEA
  throughout the review cycle
• Because the ISA is a core component of the
  review, it is essential that NCEA has the
  resources to complete it in a timely manner

4
(No Transcript)
5
(No Transcript)
6
HHRA Activities and Assessments Used by OAQPS
Residual Risk

• The Residual Risk program is the Agencys primary
  risk-based program to specifically address
  emissions of air toxics from stationary sources
• NCEAs IRIS database is the primary source of
  health information for the risk assessments that
  support the Residual Risk program
• OAQPS performs exposure and risk assessments for
  each source category covered by the residual risk
  program
• Over 150 source categories
• Each source category emits one or more air toxics
• Both chronic and acute health risks included in
  assessments
• Risk assessments are based on dose-response
  values, mainly from IRIS
• We are committed to using the best available
  scientific information as the basis for our risk
  assessmentsIRIS is our preferred source
• OAQPS currently plans to complete residual risk
  assessments on 40 to 50 source categories in the
  next 2 to 3 years
• OAQPS staff work with NCEA staff annually to
  identify priority pollutants to target for new
  assessments or reassessments

7
HHRA Activities and Assessments Used by OAQPS
Expert Advice on Models and Methods

• NCEA provides further support for OAQPS
  activities through consultation on assessment
  models, methods, and approaches, in part through
  participation in workgroups
• Review and advise on scope and methods plans,
  exposure and risk assessment reports, response to
  technical comments for NAAQS
• For example, NCEA provides assistance in
  interpretation of health effects evidence related
  to
• Selection of appropriate health endpoints for
  NAAQS risk assessments
• Selection of exposure-response and
  concentration-response relationships
• Addressing various issues such as choice of lag
  models, single vs. multi-pollutant models, single
  vs. multi-city effect estimates
• NCEA provides support in characterizing science
  related to Estimation of Policy-Relevant
  Background, used in risk assessment
• NCEA provides advice on exposure models, as well
  as scientific information used as inputs in
  exposure assessments conducted for NAAQS reviews