Tropospheric O3 column estimates are produced and evaluated from spaceborne O3 observations by the subtraction of assimilated O3 profile observations from total column observations, the so-called Tropospheric O3 ReAnalysis or TORA method. Here we apply the TORA method to six years (1996–2001) of ERS-2 GOME/TOMS total O3 and 5 ERS-2 GOME O3 profile observations using the TM5 global chemistry-tra...

To determine whether elevated CO2 reduces or exacerbates the detrimental effects of O3 on aspen (Populus tremuloides Michx.). aspen clones 216 and 271 (O3 tolerant), and 259 (O3 sensitive) were exposed to ambient levels of CO2 and O3 or elevated levels of CO2, O3, or CO2 + O3 in the FACTS II (Aspen FACE) experiment, and physiological and molecular responses were measured and compared. Clone 259...

US surface O3 responds to varying global-toregional precursor emissions, climate, and extreme weather, with implications for designing effective air quality control policies. We examine these conjoined processes with observations and global chemistry-climate model (GFDLAM3) hindcasts over 1980–2014. The model captures the salient features of observed trends in daily maximum 8 h average O3: (1) ...

Perchlorate (ClO4(-)) interferes with uptake of iodide in humans. Emission inventories do not explain observed distributions. Ozone (O3) is implicated in the natural origin of ClO4(-), and has increased since pre-industrial times. O3 produces ClO4(-)in vitro from Cl(-), and plant tissues contain Cl(-) and redox reactions. We hypothesize that O3 exposure may induce plant synthesis of ClO4(-). We...

The objective of this study was to compare the efficiency of O3/granular activated carbon (GAC) to enhance ozone transformation into OH radicals, with the common advanced oxidation processes (O3/OH , O3/H2O2). The results obtained with model systems under the given experimental conditions showed that the system O3/OH (pH 9) and O3/H2O2 (pH 7, [H2O2] = 1 10 -5 M) are more efficient than O3/GAC (...

Chamber experiments on juvenile trees have resulted in severe injury and accelerated loss of leaves along with reduced biomass production under chronically enhanced O3 levels. In contrast, the few studies conducted on adult forest trees in the field have reported low O3 sensitivity. In the present study, young beech in phytotrons was more sensitive to O3 than adult beech in the field, although ...

Prescribed rangeland burning in April is a long-standing practice in the Flint Hills region of eastern Kansas to maintain the tallgrass prairie ecosystem. The smoke plumes originating from these fires increases ambient PM2.5 concentrations and potentially contributes to ozone (O3) exceedances in downwind communities. Source apportionment research using Unmix modeling has been utilized to estima...

Measurements of surface O3 and carbon monoxide (CO) were made from September 2009 to August 2011 at Dangxiong (30.48°N, 91.10°E, 4187 m a.s.l.), a remote highland site in a southern valley of the Nyainqêntanglha Mountains in the Tibetan Plateau, China. The monthly mean O3 mixing ratio ranged from 29.1 to 51.4 ppb, with an average of 38.5 ppb, and the maximum value was observed in May. The avera...

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...

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...