The degradation of trace gases and pollutants in the troposphere is dominated by their reaction with hydroxyl radicals (OH). The importance of OH rests on its high reactivity, its ubiquitous photochemical production in the sunlit atmosphere, and most importantly on its regeneration in the oxidation chain of the trace gases. In the current understanding, the recycling of OH proceeds through HO2 reacting with NO, thereby forming ozone. A recent field campaign in the Pearl River Delta, China, quantified tropospheric OH and HO2 concentrations and turnover rates by direct measurements. We report that concentrations of OH were three to five times greater than expected, and we propose the existence of a pathway for the regeneration of OH independent of NO, which amplifies the degradation of pollutants without producing ozone.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1126/science.1164566 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Inorganic substrates in frozen solutions: Transformation mechanisms and interactions with organic compounds - A review.
Water Res
December 2024
Advanced Interdisciplinary Institute of Environment and Ecology, Guangdong Provincial Key Laboratory of Wastewater Information Analysis and Early Warning, Beijing Normal University, Zhuhai 519087, China. Electronic address:
In cold environments, such as polar regions and high latitudes, the freezing of aqueous solutions plays a crucial role in releasing and transforming nutrients, organic compounds, and trace gases. Freezing processes typically affect biogeochemical cycles and environmental processes by reducing the rate of chemical reactions. However, substantial studies have found that some chemical reactions may accelerate unexpectedly under freezing conditions.
View Article and Find Full Text PDFDual-Gas Sensor Employing Wavelength-Stabilized Tunable Diode Laser Absorption Spectroscopy and H-Infinity Filtering Algorithm.
Appl Spectrosc
January 2025
School of Mathematics Physics and Finance, Anhui Polytechnic University, Wuhu, China.
A compact dual-gas sensor based on the two near-infrared distributed feedback diode lasers and a multipass cell has been established for the simultaneous measurement of methane (CH) and acetylene (CH). The time division multiplexing calibration-free direct absorption spectroscopy is used to eliminate the cross interference in the application of multicomponent gas sensors. A wavelength stabilization technique based on the proportion integration differentiation feedback control is developed to suppress laser wavelength drift and an H-infinity (H) filter algorithm to reduce the system noise.
View Article and Find Full Text PDFImpact of trace metal supplementation on anaerobic biological methanation under hydrogen and carbon dioxide starvation.
NPJ Biofilms Microbiomes
January 2025
Department of Biology, University of Padua, via U. Bassi 58/b, 35131, Padova, Italy.
Biomethanation is a crucial process occurring in natural and engineered systems which can reduce carbon dioxide to methane impacting the global carbon cycle. However, little is known about the effect of on-and-off gaseous provision and micronutrients on bioconversion. Here, anaerobic microbiomes underwent intermittent feeding with incremental starvations and selective metal supplementation to assess the impact of hydrogen and carbon dioxide availability on microbial physiology.
View Article and Find Full Text PDFThe value of returning a sample of the Martian atmosphere.
Proc Natl Acad Sci U S A
January 2025
Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, CA 90095.
The elemental and isotopic abundances of major species in the Martian atmosphere have been determined, but analyses often lack sufficient precision, and those of minor and trace species are frequently not well known. Many important questions about the evolution and current state of Mars require the kind of knowledge that can be gained from analysis of a returned sample of the Martian atmosphere. Key target species include the noble gases, nitrogen, and various species containing carbon, hydrogen, and oxygen, such as methane.
View Article and Find Full Text PDF21 century surface UV radiation changes deduced from CMIP6 models: part I-evolution of major influencing factors.
Photochem Photobiol Sci
January 2025
Institute of Meteorology and Climate Research Atmospheric Trace Gases and Remote Sensing, Karlsruhe Institute of Technology, Karlsruhe, Germany.
For a given solar elevation, the levels of solar ultraviolet radiation at the Earth's surface are determined by the amounts of ozone, aerosols, and clouds, as well as by the reflectivity of the surface. Here, we study the evolution of these factors for three selected decades in the period 1950-2100 using results from simulations with Earth-System models (ESMs) participating in the 6 phase of the Coupled Model Intercomparison Project (CMIP6). The simulations for the future are based on three Shared Socioeconomic Pathways: SSP1-2.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!