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Laboratory studies of atmospheric chemistry characterize the nature of atmospherically relevant processes down to the molecular level, providing fundamental information used to assess how human activities drive environmental phenomena such as climate change, urban air pollution, ecosystem health, indoor air quality, and stratospheric ozone depletion. Laboratory studies have a central role in addressing the incomplete fundamental knowledge of atmospheric chemistry. This article highlights the evolving science needs for this community and emphasizes how our knowledge is far from complete, hindering our ability to predict the future state of our atmosphere and to respond to emerging global environmental change issues. Laboratory studies provide rich opportunities to expand our understanding of the atmosphere via collaborative research with the modeling and field measurement communities, and with neighboring disciplines.

Self-assembled monolayers (SAMs) of vinyl-terminated 3- and 8-carbon compounds were generated on Si substrates and reacted at room temperature with approximately 1 ppm gaseous O(3). A combination of atomic force microscopy (AFM), scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used to study the surface composition and morphology after oxidation. A distribution of large ( approximately 0.1-10 microm) organic aggregates was formed, while the surrounding substrate became depleted of carbon compared to the unreacted SAM. This highly unusual result establishes that the mechanism of ozonolysis of alkene SAMs must have a channel that is unique compared to that in the gas phase or in solution, and may involve polymerization induced by the Criegee intermediate (CI). Oxidation at 60% RH led to the formation of a number of smaller aggregates, suggesting water intercepted the CI in competition with aggregate formation. The uptake of water, measured using transmission FTIR, was not increased upon oxidation of these films. In conjunction with literature reports of polymer formation from VOC-NO(x) photooxidations, these results suggest that formation of aggregates and polymers in the atmosphere is much more widespread than previously thought. The implications for the ozonolysis of alkenes on surfaces, for the transformation of organics in the atmosphere, and for the reactions and stability of unsaturated SAMs, are discussed.

The vast consumption of nitrogen-based fertilizers is a significant source of environmental pollutants in all phases. While enhanced-efficiency nitrogen fertilizers (EENFs) improve N-use efficiency and reduce environmental impact, their performance depends on local conditions. Here, we present a relatively simple soil–fertilizer–plants greenhouse setup for the multi-phase tracking of N species of the effects of EENFs. We compared the environmental and agronomic performance of three urea-based EENFs (urea embedded with urease inhibitors, 2-month, and 4-month controlled release urea) and the common split surface application of the granulated urea. We tested the fertilizer applications on basil seedlings for three consecutive growing cycles. The analyses carried out included nitrogen recovery in plant biomass, soil, drainage, and NH3 and N2O emissions. This multi-phase research indicates that tested EENFs perform better than the standard surface-applied urea. The four-month controlled-release urea fertilizer matched the basil N demand the best, significantly increasing yield and improving nitrogen use efficiency while reducing NO3− leaching and NH3 and N2O emissions. The presented soil–fertilizer–plants experimental setup provides a relatively easy-to-handle system for the comprehensive tracking of N dynamics, including plant response. It allows stakeholders to estimate and improve fertilization sustainability. [ABSTRACT FROM AUTHOR]

The nitrogen dioxide (NO2) fluxes released into the gas phase during the continuous photolysis of nitrate ions (NO3-) at 300 nm, in the submillimeter ice layers produced by freezing aqueous KNO3 sprays on cold surfaces are quantitatively estimated. Results suggest that the NO3- photolysis in ice takes place in a liquid like environment and the actual flux values depends on the morphology of ice crystals.

The chronology of the Sea of Galilee is compared to levels of lead in soil samples from different depths of the sea bed. Lead samples show a gradual rise in lead levels since 1920, with abrupt changes during different events such as the drying out of the Hula Swamp. Lead concentration statistics are prepared chronologically in charts and graphs.

Studies of the oxidation of the three-carbon and eight-carbon vinyl-terminated self-assembled monolayers on a silicon attenuated total reflectance (ATR) crystal by gas-phase ozone at 296K are reported. Possible mechanisms of the ozonolysis and its atmospheric implications are discussed.

The quantum yield, (empty set), of nitrite formation in the 302 nm band photolysis of fluid or frozen aqueous nitrate solutions increases monotonically with temperature over the range 238-294 K. It is found that the nitrite dispersed into the bulk is subsequently degraded by OH radicals and suggests that the photochemically relevant properties of the quasi-liquid layer covering ice below the normal melting point resemble those of bulk supercooled water.