Orange trees are widely cultivated in regions with high concentrations of tropospheric ozone. Citrus absorb ozone through their stomata and emit volatile organic compounds (VOC), which, together with soil emissions of NO, contribute to non-stomatal ozone removal. In a Valencia orange orchard in Exeter, California, we used fast sensors and eddy covariance to characterize water and ozone fluxes. ...

The role of stomata in regulating photosynthesis and transpiration, hence governing global biogeochemical cycles climate, is well-known. Less well-understood, however, the importance stomatal control to exchange other trace gases between terrestrial vegetation atmosphere. Yet these determine atmospheric composition, air quality on scales ranging from local global, seconds decades. Vegetation a ...

We use a 3-D regional atmospheric chemistry transport model (WRF-Chem) to examine ozone dry deposition in East Asia, which is an important but uncertain research area because of insufficient observation and numerical studies focusing on East Asia. Here we compare two widely used dry deposition parameterization schemes, the Wesely and M3DRY schemes, which are used in the WRF-Chem and Community M...

Ozone/TEOS thermal chemical vapor deposition ~CVD! has been investigated for SiO2 deposition on Si, using a cold-wall research reactor equipped to determine the effects of precursor concentration, deposition temperature ~300–500 °C!, and pressure ~30–200 Torr! on deposition rates, etch rates, and step coverage in the regime of subatmospheric CVD ~SACVD!. Deposition rates first increase with sub...

The Citrus genus includes a large number of species and varieties widely cultivated in the Central Valley of California and in many other countries having similar Mediterranean climates. In the summer, orchards in California experience high levels of tropospheric ozone, formed by reactions of volatile organic compounds (VOC) with oxides of nitrogen (NOx). Citrus trees may improve air quality in...

Although there has been a great deal of research on ozone, interest in exposure of native, herbaceous species is relatively recent and it is still not clear what role the pollutant has in their ecological fitness. The ozone exposure of a plant is usually expressed in terms of the concentration above the canopy or as a time-weighted index. However, to understand the physiological effects of ozon...

In this study, asphaltene deposition from crude oil has experimentally and theoretically been studied using a test loop and an accurate temperature monitoring during a laminar flow. The effects of oil velocity and surface temperature on the thickness of asphaltene deposition were investigated. The results show that asphaltene deposition thickness increases by increasing surface temperature. As ...

A dry deposition modeling approach that includes vegetation-atmosphere interactions through photosynthesis/carbon assimilation relationships was recently developed. In this approach, gas deposition velocity (Vd) is calculated using an electrical resistance-analog approach in a coupled soil-vegetation-atmosphere transfer (SVAT) model. For this, a photosynthesis-based model is dynamically coupled...

In this manuscipt, Zhao et al. present the results of an exploratory modeling study that quantifies the potential impact of anthropogenic nitrogen deposition on ozone air quality. The GEOS-Chem chemical transport model is used to derive nitrogen deposition fields (with and without anthropogenic emissions) that are used in separate Community Land Model simulations in order to derive contrasting ...