title: Effects of fresh and aged vehicular exhaust emissions on breathing pattern and cellular responses--pilot single vehicle study.
abstract: The study presented here is a laboratory pilot study using diluted car exhaust from a single vehicle to assess differences in toxicological response between primary emissions and secondary products resulting from atmospheric photochemical reactions of gas phase compounds with O₃, OH and other radicals. Sprague Dawley rats were exposed for 5 h to either filtered room air (sham) or one of two different atmospheres: (i) diluted car exhaust (P)+Mt. Saint Helens Ash (MSHA); (ii) P+MSHA+secondary organic aerosol (SOA, formed during simulated photochemical aging of diluted exhaust). Primary and secondary gases were removed using a nonselective diffusion denuder. Continuous respiratory data was collected during the exposure, and bronchoalveolar lavage (BAL) and complete blood counts (CBC) were performed 24 h after exposure. ANOVA models were used to assess the exposure effect and to compare those effects across different exposure types. Total average exposures were 363 ± 66 μg/m³ P+MSHA and 212 ± 95 µg/m³ P+MSHA+SOA. For both exposures, we observed decreases in breathing rate, tidal and minute volumes (TV, MV) and peak and median flows (PIF, PEF and EF50) along with increases in breathing cycle times (Ti, Te) compared to sham. These results indicate that the animals are changing their breathing pattern with these test atmospheres. Exposure to P+MSHA+SOA produced significant increases in total cells, macrophages and neutrophils in the BAL and in vivo chemiluminescence of the lung. There were no significant differences in CBC parameters. Our data suggest that simulated atmospheric photochemistry, producing SOA in the P+MSHA+SOA exposures, enhanced the toxicity of vehicular emissions.
authors.affiliation: Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA. eadiaz@hsph.harvard.edu
authors.forename: Edgar A
authors.initials: EA
authors.lastname: Diaz
authors.forename: Yeonseung
authors.initials: Y
authors.lastname: Chung
authors.forename: Vasileios
authors.initials: V
authors.lastname: Papapostolou
authors.forename: Joy
authors.initials: J
authors.lastname: Lawrence
authors.forename: Mark S
authors.initials: MS
authors.lastname: Long
authors.forename: Vivian
authors.initials: V
authors.lastname: Hatakeyama
authors.forename: Brenno
authors.initials: B
authors.lastname: Gomes
authors.forename: Yasser
authors.initials: Y
authors.lastname: Calil
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Sato
authors.forename: Petros
authors.initials: P
authors.lastname: Koutrakis
authors.forename: John J
authors.initials: JJ
authors.lastname: Godleski
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D000818:Animals; D001772:Blood Cell Count; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000166:cytology; D008297:Male; D052638:Particulate Matter / Q000633:toxicity*; D010865:Pilot Projects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012119:Respiration / Q000187:drug effects*; D001335:Vehicle Emissions / Q000633:toxicity*; D055549:Volatile Organic Compounds / Q000633:toxicity*
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D001335:Vehicle Emissions; D055549:Volatile Organic Compounds