Transformations of Selected Organic Urban HAPs: Mechanistic and Modeling Studies to Identify Cancer and Non-Cancer Human Health Risk

EPA Grant Number: R826247
Title: Transformations of Selected Organic Urban HAPs: Mechanistic and Modeling Studies to Identify Cancer and Non-Cancer Human Health Risk
Investigators: Jeffries, Harvey E.
Institution: University of North Carolina at Chapel Hill
EPA Project Officer: Chung, Serena
Project Period: December 8, 1997 through December 7, 2000
Project Amount: $540,000
RFA: Ambient Air Quality (1997) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Air


1) To advance fundamental knowledge of atmospheric transformation of organic hazardous air pollutants. Initially, 1,3-butadiene, aromatics and epoxides will be studied; in subsequent years this will expand to other HAPs. (2) To include the large variety of organic HAPs in modern air quality models by extensions of the newly developed "morphecules" concept. (3) To design and prepare a HAPs mixture for testing HAPs behavior in an urban-like environment and for evaluating the allomorphic/morphecule representation and other mechanisms for air quality models. (4) To perform risk calculations for the purpose of comparing the potential cancer and noncancer risks of the reacting precursors and products in our urban-like outdoor reaction chambers.


The approach will be to identify and quantify reaction intermediates and products from atmospheric transformation of select HAPs by applying newly developed analytical techniques, which include identification and detection of aldehydes and ketones by their PFBHA derivatives using GC/MS. The product results, along with the kinetics knowledge available in the literataure, will be used to construct transformation mechanisms for 52 organic HPAPs that contain carbon, hydrogen, or oxygen. Such explicit mechanisms will then be converted into allomorphic/morphecule representations. In the meantime, an appropriately composed organic HAPs mixture will be designed and prepared, and outdoor smog chamber experiments will be conducted on the mixture and on individual components under simulated urban atmospheric conditions. The chamber observational data will be used to study the behior of HAPs in an urban-like environment and to evaluate the allomorphic transformation mechanisms. In addition, the resesarchers will perform risk calculations using the new mechanistic data on precursor and product HAPs for the purpose of comparing the potential cancer and noncancer risks of the precursors and products. The risk calcuations will be used to guide the selection of HAPs and their products for further experiments. The calculations will also help to identify transformed species represented as reacting entities in the allomorphic mechanisms.

Expected Results:

The primary results of this study will be publications on the transformation chemistry of important organic HAPs; the development of allomorphic mechanisms of HAP formation and decay; and the conversion of conceptual chemistry into mathematical representations that can be used in future air quality modeling. The primary benefit from these results will be reduction in the uncertainty concerning atmospheric transformation of organic HAPs, which can then be translated into more certain and realistic estimates of the human health risks from HAPs. Another result be will be production of an optimized synthetic HAP mixture well-suited for chamber testing, and a substantial observational data set from the UNC outdoor smog chamber to be used to formulate and evaluate new reaction mechanisms for HAPs. Another benefit will be a set of reaction mechanisms potentially useful for integrating HAPs transformations into air quality models. This step will significantly help with regulatory quantitative risk analysis and decision-making.

Publications and Presentations:

Publications have been submitted on this project: View all 13 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 1 journal articles for this project

Supplemental Keywords:

Atmospheric chemistry, air quality models, outdoor smog chamber, organic Hazardous Air Pollutants, photochemical reaction mechanisms, risk assessment, RFA, Health, Air, Toxics, air toxics, HAPS, Risk Assessments, tropospheric ozone, cancer risk, ambient air quality, atmospheric, fate and transport, health effects, model, monitoring, risk, risk assessment, urban air toxics, urban air, exposure and effects, air pollutants, aldehydes, morphecules, outdoor smog chamber, ketone, air quality models, ambient air, hazardous air pollutants, air quality criteria, ambient monitoring, atmospheric transformation, chemical composition, modeling, smog, urban air pollutants, air pollution models, air quality data, human exposure, cancer, carcinogens, hazardous air pollutants (HAPs), urban air pollution, epoxides, ketones, environmental effects, human health, photochemical reaction mechanism, cancer risk assessment, molecular biology, 1, 3-Butadiene, atmospheric chemistry, transport

Progress and Final Reports:

  • 1998 Progress Report
  • 1999 Progress Report
  • Final Report