Discussion.
Organized by Ralph Delfino, David Diáz-Sánchez, Alison Elder, Diane Gold, Kent Pinkerton.
Led by Alison Elder (Rochester Particulate Matter Center).

Questions:
• Which host characteristics have been consistently identified that modify PM responses in epidemiological, clinical, and animal studies?
• Have we adequately accounted for individual variability in antioxidant status when we assess oxidative stress and inflammation in response to PM?
• How does the tissue site for sampling affect our ability to assess antioxidant and oxidant stress responses? At what time point following exposure?
• How important are shifts of critical cell types from the blood to target tissue. or shifts in the activation states of these cells in terms of measuring outcome?
• How do we account for genotype and/or phenotype as they relate to PM susceptibility?
• How can we leverage large cohort studies, including intervention studies, to understand mechanisms of pollution effects, including gene-by-environment interactions?
• What other diseases should we be thinking about in regards to PM susceptibility and how strong is the evidence that there is a PM-related issue?
• What mechanisms are shared amongst the target organ systems and where might the mechanisms diverge in regards to susceptibility to PM?

Alison Elder’s discussion notes.

Topical Discussion: Are we ready for multi-pollutant research?
Organized by Michelle Bell, Alison Geyh, Ian Gilmour, Phil Hopke, Mike Kleinman, Petros Koutrakis, and Anthony Wexler.
Led by Alison Geyh (Johns Hopkins Particulate Research Center).

• Topic Area 1: Measuring and Collecting Source-Oriented Air Pollutants. Anthony Wexler (San Joaquin Valley Aerosol Health Effects Center)
  
• Topic Area 2: Using Air Quality Models to Estimate Exposure to Pollutant Mixtures. Mike Kleeman (San Joaquin Valley Aerosol Health Effects Center)
  
• Topic Area 3: Multi-pollutant Health Effects: Exposure Assessment Challenges. Petros Koutrakis (Harvard/EPA Center for Ambient Particle Health Effects)
  
• Topic Area 4: Toxicology Outcomes Following Exposure to Air Pollutant Mixtures: Are we there yet? M. Ian Gilmour (US EPA)
  
• Topic Area 5: Challenges for Evaluating the Health Effects of Pollutant Mixtures. Michelle Bell (Johns Hopkins Particulate Research Center).

• Topic Area 1: Human subpopulations with unique susceptibility to PM. Annette Peters (Rochester Particulate Matter Center)
• Topic Area 2: Animal studies of populations with unique susceptibility to the effects of PM. Skip Garcia (Johns Hopkins Particulate Research Center)
• Topic Area 3: Genetic Susceptibility and Epigenetic Mechanisms of Response to PM. David Diáz-Sánchez (US EPA)

Questions:
• Can we disentangle the impact of genetic susceptibility and disease status?
• What is the evidence that particle properties matter when we assess susceptibility?
• What role do dietary anti-oxidants play in modifying the responses to PM?
• How do we translate PM-dysregulated biological processes in animals into susceptible human populations? What are the potential pitfalls with linking PM-specific physiological outcomes to a particular gene, generation of PM biomarkers, and validation in humans?
• How do we study inhaled particle translocation?
• What are the relevant animal models for specific PM-induced health disorders?
• What are the epigenetic changes impacted by PM?
• How can epigenetic differences confer susceptibility to PM?
• Can we use epigenetic changes as biomarkers of exposure or susceptibility?
• How important are trans-generational effects of PM?
• How important is genetics in epigenetic determination of susceptibility?