The heterogeneous reaction between O3 and authentic Saharan dust surfaces was investigated in a Knudsen reactor at≈ 296 K. O3 was destroyed on the dust surface and O2 was formed with conversion efficiencies of 1.0 and 1.3 molecules O2 per O3 molecule destroyed for unheated and heated samples, respectively. No O3 desorbed from exposed dust samples, showing that the uptake was irreversible. The u...

Saplings of six Finnish hybrid aspen (Populus tremuloides Michx. x P. tremula L.) clones were exposed to 0, 50, 100 and 150 ppb ozone (O3) for 32 days in a chamber experiment to determine differences in O3 sensitivity among genotypes. Based on the chamber experiment, three clones with intermediate sensitivity to O3 were selected for a free-air O3 enrichment experiment in which plants were expos...

Because forest fires emit substantial NOx and hydrocarbons--known contributors to O3 production--we hypothesize that interannual variation in western U.S. O3 is related to the burned area. To evaluate this hypothesis we used a gridded database of western U.S. summer burned area (BA) and biomass consumed (BC) by fires between 101-125 degrees W. The fire data were compared with daytime summer O3 ...

[1] We use a chemical transport model (GEOS-CHEM) to quantify the contribution of long-range transported pollution to the European ozone (O3) budget for the year 1997. The model reproduces the main features observed over Europe for O3, carbon monoxide and nitrogen dioxides, as well as two events of enhanced O3 of North American origin over the eastern North Atlantic and over Europe. North Ameri...

[1] Reducing methane (CH4) emissions is an attractive option for jointly addressing climate and ozone (O3) air quality goals. With multidecadal full-chemistry transient simulations in the MOZART-2 tropospheric chemistry model, we show that tropospheric O3 responds approximately linearly to changes in CH4 emissions over a range of anthropogenic emissions from 0–430 Tg CH4 a 1 (0.11–0.16 Tg tropo...

Coupled cluster CCSD(T) calculations using the aug-cc-pVQZ basis set were performed on structures and energies of complexes O3-HF, O3-HCl, O3-OH, O3-H2, O3-N2, O3-CO, O3-O2, O3-F2, O3-Cl2, O3-ClF. Most have Cs symmetry, with symmetry plane being ozone (for hydrogen bonded O3-HF to O3-OH for halogen O3-Cl2 O3-ClF) or perpendicular most others). Dissociation De range from 718 1137 cm−1 O3-HCl com...

In this study, we investigated the effects of ozone (O3) exposure on expression of cell-surface molecules associated with antigen presentation and on accessory activity of bronchoalveolar lavage cells (BAL cells). Rats were exposed to 1 ppm O3 for 3 days. Expression of cell-surface molecules was measured by flow cytometry. Accessory activity of BAL cells was assessed by the allogeneic mixed lym...

We tested the hypothesis that oxidative stress and biological effect after ozone (O3) exposure are dependent on changes in iron homeostasis. After O3 exposure, healthy volunteers demonstrated increased lavage concentrations of iron, transferrin, lactoferrin, and ferritin. In normal rats, alterations of iron metabolism after O3 exposure were immediate and preceded the inflammatory influx. To tes...

To determine the influence of exercise on pulmonary dose of inhaled pollutants, we compared biomarkers of inhaled ozone (O3) dose and toxic effect between exercise levels in humans, and between humans and rats. Resting human subjects were exposed to labeled O3 ((18)O3, 0.4 ppm, for 2 hours) and alveolar O3 dose measured as the concentration of excess (18)O in cells and extracellular material of...

Ozone (O3) is a serious public health concern. Recent findings indicate that the damaging health effects of O3 extend to multiple systemic organ systems. Herein, we hypothesize that O3 inhalation will cause downstream alterations to the liver. To test this, male Sprague-Dawley rats were exposed to 0.5ppm O3 for 8h/day for 5 days. Plasma liver enzyme measurements showed that 5 day O3 exposure di...