CARB Research Seminar

This page updated June 19, 2013

The Effect of Smoke from Burning Vegetative Residues on Airway Inflammation and Pulmonary Function in Healthy, Asthmatic and Allergic Individuals

Colin Solomon, Ph.D., University of California, San Francisco; with Bryan Jenkins, Ph.D., University of California, Davis; and John R. Balmes, M.D., San Francisco General Hospital

July 08, 2003
Cal EPA Headquarters, 1001 "I" Street, Sacramento, CA

Research Project


Open field burning is used to clear agricultural fields of rice straw residues and for disease and pest control. Although the resulting smoke contains respirable particulate and gaseous components, there is no information available on the effects of rice straw smoke (RSS) exposure on respiratory health. This project investigated two hypotheses: 1) that airway inflammation would be increased and spirometric pulmonary function decreased, as a function of RSS concentration and dose, and 2) that RSS-induced changes in airway inflammation and spirometric pulmonary function would be greater in asthmatic and allergic individuals than healthy individuals. Exposure conditions (30 min) included Filtered Air (FA) and RSS at concentrations of 200 µg/m3 and 600 µg/m3, and a three serial-day exposure to RSS at a concentration of 200 µg/m3. Bronchoscopy was conducted 6-hour post-exposure. Pulmonary function, which was measured pre- and post-exposure and pre-bronchoscopy, did not change in under any of the exposure conditions. Cellular and biochemical analysis of the fluid recovered at bronchoalveolar lavage showed indications of airway inflammation in all three subject groups. Healthy, allergic, or asthmatic subjects had similar responses. The results of this project indicate that RSS is capable of inducing airway inflammation in healthy individuals and in individuals with asthma or allergic rhinitis.

Speaker Biography

Colin Solomon received his doctorate in Physiology from the University of Queensland, Australia. He is currently an Assistant Professor in the Department of Medicine at the University of California, San Francisco. Dr. Solomon investigates the mechanisms of toxin-induced (gas and particle) airway inflammation in humans, using controlled exposure experiments.

Bryan Jenkins received his doctorate in Engineering from the University of California, Davis. He currently is Professor of Biological and Agricultural Engineering at UC Davis. Dr. Jenkins teaches and conducts research in the areas of energy and power systems, with research emphasis in thermal conversion of biomass materials including reaction processes, high temperature inorganic transformations, and emissions from controlled and uncontrolled combustion and gasification processes.

John R. Balmes received his doctorate in medicine from the Mount Sinai School of Medicine. He is a Professor in the Department of Medicine at the University of California, San Francisco, Chief of the Division of Occupational and Environmental Medicine at San Francisco General Hospital, and Director of the Northern California Center for Occupational and Environmental Health. Dr. Balmes investigates the effects of various air pollutants on airway inflammation and respiratory health in humans, using controlled human exposure and epidemiologic studies.

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