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NOx

About: NOx is a research topic. Over the lifetime, 26367 publications have been published within this topic receiving 496555 citations.


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Journal ArticleDOI
01 Jul 2003-Fuel
TL;DR: In this paper, the authors investigated the performance of coal combustion with O 2 /CO 2 with heat recirculation and showed that the conversion ratio from fuel-N to exhausted NO in O 2/CO 2 pulverized coal combustion was only one fourth of conventional coal combustion.

117 citations

Journal ArticleDOI
TL;DR: In this article, the interaction of sulfur dioxide with a commercial NOx storage-reduction catalyst (NSR) has been investigated using in situ IR and X-ray absorption spectroscopy.

117 citations

Journal ArticleDOI
TL;DR: In this article, the authors obtained the continuous spectra of the real and imaginary refractive indices (m = n-i k) in the ultraviolet (UV)-to-visible region using spectroscopic ellipsometry for n and UV-visible spectrometry for k.
Abstract: . Secondary organic material (SOM) produced by the oxidation of anthropogenic volatile organic compounds can be light-absorbing (i.e., brown carbon). Spectral data of the optical properties, however, are scarce. The present study obtained the continuous spectra of the real and imaginary refractive indices (m = n-i k) in the ultraviolet (UV)-to-visible region using spectroscopic ellipsometry for n and UV–visible spectrometry for k. Several different types of SOM were produced in an oxidation flow reactor by photooxidation of toluene and m-xylene for variable concentrations of nitrogen oxides (NOx). The results show that the k values of the anthropogenically derived material were at least 10 times greater than those of the biogenically derived material. The presence of NOx was associated with the production of organonitrogen compounds, such as nitro-aromatics and organonitrates, which enhanced light absorption. Compared with the SOM derived from m-xylene, the toluene-derived SOM had larger k values, as well as a greater NOx-induced enhancement, suggesting different brown-carbon-forming potentials of different aromatic precursor compounds. The results imply that anthropogenic SOM produced around urban environments can have an important influence on ultraviolet irradiance, which might consequently influence photochemical cycles of urban pollution.

116 citations

Journal ArticleDOI
TL;DR: In this paper, a series of WO 3 -doped Mn-Zr mixed oxide catalysts were investigated for the selective catalytic reduction of NO x by NH 3 (NH 3 -SCR).

116 citations

Journal ArticleDOI
TL;DR: In this paper, the GEOS-Chem global tropospheric chemistry model was extended to include multiphase halogen (Br-Cl) chemistry and HOBr+Br-/Cl- was found to be the dominant gas phase reservoir of inorganic bromine.
Abstract: Aircraft and satellite observations indicate the presence of ppt (pptpmol/mol) levels of BrO in the free troposphere with important implications for the tropospheric budgets of ozone, OH, and mercury. We can reproduce these observations with the GEOS-Chem global tropospheric chemistry model by including a broader consideration of multiphase halogen (Br-Cl) chemistry than has been done in the past. Important reactions for regenerating BrO from its nonradical reservoirs include HOBr+Br-/Cl- in both aerosols and clouds, and oxidation of Br- by ClNO3 and ozone. Most tropospheric BrO in the model is in the free troposphere, consistent with observations and originates mainly from the photolysis and oxidation of ocean-emitted CHBr3. Stratospheric input is also important in the upper troposphere. Including production of gas phase inorganic bromine from debromination of acidified sea salt aerosol increases free tropospheric Br-y by about 30%. We find HOBr to be the dominant gas-phase reservoir of inorganic bromine. Halogen (Br-Cl) radical chemistry as implemented here in GEOS-Chem drives 14% and 11% decreases in the global burdens of tropospheric ozone and OH, respectively, a 16% increase in the atmospheric lifetime of methane, and an atmospheric lifetime of 6months for elemental mercury. The dominant mechanism for the Br-Cl driven tropospheric ozone decrease is oxidation of NOx by formation and hydrolysis of BrNO3 and ClNO3.

116 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
20231,699
20223,249
20211,405
20201,353
20191,367