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Health Effects of Air Pollution: Beyond the “Criteria” Pollutants

Health Effects of Air Pollution: Beyond the “Criteria” Pollutants. Philip Bromberg MD 1 Ilona Jaspers PhD 1 Ken Sexton PhD 1 Harvey Jeffries PhD 1 W. Michael Foster PhD 2 1 Univ. North Carolina 2 Duke University Air Toxics Workshop II Session 1 12 June 07 Mickey Leland Center

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Health Effects of Air Pollution: Beyond the “Criteria” Pollutants

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  1. Health Effects of Air Pollution:Beyond the “Criteria” Pollutants Philip Bromberg MD1 Ilona Jaspers PhD1 Ken Sexton PhD1 Harvey Jeffries PhD1 W. Michael Foster PhD2 1 Univ. North Carolina 2 Duke University Air Toxics Workshop II Session 1 12 June 07 Mickey Leland Center Houston, TX

  2. Introduction • Ozone (O3) • Produced in ambient air by photochemistry of NOx and hydrocarbons (primary emissions) • High reactivity -> ozonized reactive biological products in airways after inhalation • E.g., 4-OH nonenal, an unsaturated aldehyde with an acrolein motif (-CH=CH-CH=O).

  3. Introduction (cont’d) • Biologic effects in humans • Irritant (bronchial C fibers and A-delta fibers) • Reversible decrease in lung function • Acute airways inflammation (IL-8, IL-6, PGE2) • Increased epithelial permeability

  4. Introduction (cont’d) • Ozone as a surrogate • Other toxic species (oxy-organics) in ambient air • Some oxy-organics are recognized “air toxics” (e.g., HCHO, acetaldehyde, acrolein) • Others remain to be identified and characterized • Ozone itself may or may not be directly involved in their formation • Interaction of poorly volatile oxy-organics with ambient particulate matter

  5. Is ozone responsible for all the health effects observed in human populations exposed to photochemical smog? • Yes, and • No!

  6. Respiratory Hospital Admissions by Daily Maximum Ozone Level, Lagged One Day (Burnett et al, 1994) 114 112 110 108 106 104 102 Respiratory Admissions .01 .02 .03 .04 .05 .06 .07 .08 .09 .1 Ozone Concentration (ppm) D-8a

  7. In-Vitro Exposure Systems Interfaced to Environmental Irradiation Chambers • Interfaced in-vitro gaseous exposure systems to these smog chambers, allowing A549 cells, an alveolar type II-like cell line, and primary human bronchial epithelial cells, grown on membranous support, to be exposed in real-time, directly to the gaseous photochemical mixture or ”control” mixture and analyzed for cytotoxicity and cytokine gene expression. • ?? Attain goal of whole natural gas-phase exposure sample • All products, both known and unknown, produce exposure; product yields and resulting mixtures are natural (realistic exposure ratios)

  8. Cytotoxicity induced by the photochemical transformation of HAPS

  9. Inflammatory gene expression induced by the photochemical transformation of HAPS : Methanol, Isoprene (ISO), 1,3-Butadiene (BD)

  10. Uncertainties in Estimating Exposure and Risk in Atmospheric Aging Effects • Many reaction rates and product yields are uncertain • Many reaction products are detected but not identified • Many reaction products are unknown or difficult to detect or quantify • How can we estimate exposure and risk given these uncertainties and unknowns ?

  11. Resuspended DP from Diesel-Urban VOC Mixtures: Effect of Photochemical Aging • Create/Obtain DEP in rooftop smog chamber at UNC • Obtain C57BL/6J mice at Duke • Day 1- Instill DEPs (6 mice per group) Dark Fresh 28.8µg/ 50µL • Photochemically Aged 30.5µg/ 50µL • PBS (phosphate buffered saline) 50µL • Dark Fresh 44.4µg/ 50µL • Dark Aged 39.0µg/ 50µL PBS (phosphate buffered saline) 50µL • Day 4- Repeat Doses in mice • Day 7- Repeat Doses in mice • Day 8- Euthanize for lavage/tissue collection or Perform PFTs

  12. * = p<0.05 * * * * * * * *

  13. HISTOLOGY PBS Control Fresh DEP Hematoxylin and Eosin (H and E) Staining- stains nucleic acids and intracellular and extracellular proteins Aged DEP

  14. * * * (p=.079) Aged DEP instilled mice showed GREATER airway hyperresponsiveness compared to the ozone exposed mice.

  15. Resuspended DP from Diesel-Urban VOC Mixtures: Effect of Photochemical Aging

  16. Summary/Conclusions • “Air Toxics” and “Criteria Pollutants” interact. They should not be treated as totally distinct categories. • Photochemistry transforms many (not all) volatile organic compounds into less volatile oxy-organics that are toxic in their own right and may interact with PM.

  17. Summary/Conclusions (cont’d) • Photochemical smog clearly causes adverse respiratory health effects, notably in asthmatics. Ozone is toxic on its own, but may also be a surrogate for toxic oxy-organic species. • Houston is positioned to lead in this area of air pollution research and application. • A multi-disciplinary team approach is required to obtain the needed information.

  18. Summary/Conclusions (cont’d) • Such knowledge is essential for • Targeted air quality monitoring • Cost-effective measures to control key emissions • Reasonable expectation that these measures will improve public health.

  19. Student Investigators • Melanie Doyle, PhD (2006) • Currently at Lovelace Resp. Res. Inst. • Kim deBruijne MS (2006) • Currently a PhD candidate at U.N.C. • Seth Ebersviller (grad. student) • Currently a PhD candidate at U.N.C.

  20. http://www.oneatmosphere.unc.edu/

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