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Effects Of Combinations of Ozone and Diesel Exhaust Exposures On Blood, Cardiac, And Lung Endpoints
Citation:
STEVENS, T., M. W. CASE, J. D. PLEIL, D. DIAZ SANCHEZ, W. CASCIO, R. B. DEVLIN, AND M. C. MADDEN. Effects Of Combinations of Ozone and Diesel Exhaust Exposures On Blood, Cardiac, And Lung Endpoints. Presented at American Thoracic Society (ATS) Meeting, San Francisco, CA, May 18 - 23, 2012.
Impact/Purpose:
These data suggest that simultaneous DE+03 exposure can synergistically alter blood parameters, and sequential DE followed by 03 exposures can Induce a greater lung function decrement than FN03 exposures; both effects appear to be in a synergistic manner.
Description:
Human subjects were exposed to combinations of 300 ppb ozone (03) and 300 ug/m3 diesel exhaust (DE) to examine if synergistic effects were observed. Subjects received either filtered air (FA), 03, DE, or DE+03 on Day 1, followed by only 03 exposures on Day 2, and a follow-up on Day 3. Exposures were for 2 hr with intermittent, moderate exercise. Venipuncture was performed pre and post on each exposure day. Preliminary data (n=8 subjects) showed blood triglyceride levels decrease of 52±16 mq/dl, immediately post DE+03 compared to pre-exposure, but other exposures did not alter triglyceride levels. For lung function on Day 1, FA and DE did not induce FEV1 changes, 03 decreased FEV1 16±3%, while DE+03 decreased FEV1 22±4% due possibly to increased N02 during exposure. Similar trends were observed for FVC values. On Day 2 post 03, subjects who were exposed to DE on day 1 had a greater FEV1 decrement (18±4%) compared to FA (11±3%). Subjects having 03 and DE+03 exposures on Day 1 had Day 2 03-. induced FEV1 decrements of 26±5% and 19±2%, respectively. Lung function recovered to approximately pre-exposure values within 4 hr at similar rates In all groups on both Days 1 and 2. Cardiac QTcDYN intervals were not altered by any exposure (n=4). These data suggest that simultaneous DE+03 exposure can synergistically alter blood parameters, and sequential DE followed by 03 exposures can Induce a greater lung function decrement than FN03 exposures; both effects appear to be in a synergistic manner. [This is an abstract of a proposed presentation and may not represent official US EPA policy. Protocol approved by the UNC Biomedical IRB]