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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
TL;DR: In this paper, a 6-week period in the summer of 1991, measurements of O3, NO, NO2, peroxyacetyl nitrate (PAN), HNO3, and NOy were made in Giles County, Tennessee, and a strong association was observed between O3 and NOx oxidation product (NOz = NOy - NOx) levels.
Abstract: Measurements of O3, NO, NO2, peroxyacetyl nitrate (PAN), HNO3, and NOy were made during a 6-week period in the summer of 1991 in Giles County, Tennessee. These data were analyzed to determine the factors controlling the relationship between O3 and NOy at this rural site. A strong association was observed between the O3 and NOx oxidation product (NOz = NOy - NOx) levels. The higher O3 levels were associated with air masses impacted by higher NOx emissions that had been photochemically processed. An analysis of the data indicates that the ultimate O3 production is about 10 molecules of O3 produced for each molecule of NOx emitted. The analysis results also suggest that O3 net production continues until about 70% of the NOx has been converted into NOz. The PAN/HNO3 ratios observed suggest that the air masses in Giles County are composed of higher volatile organic carbon/NOx ratios than the air masses observed at other rural sites in eastern North America. A comparison of the data analysis results to model simulations and smog chamber experiments suggests that most of the time, Giles County is in an NOx-limited regime for O3 production.

169 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the performance of a single-cylinder diesel compression ignition engine with a dual fuel (biodiesel-CNG) combustion system and showed that the performance can be optimized for biodiesel and CNG dual fuel combustion by advancing the pilot injection timing for low loads and delaying the injection timing to compensate for high loads.

168 citations

Journal ArticleDOI
01 Jan 1998
TL;DR: In this paper, the effect of fuel type on the NO-NO2 conversion was investigated in the low temperature range and showed a strong dependence on fuel type, and the interaction between the NO and NO2 reactions and the oxidation reactions of the fuel in the lower temperature range was analyzed.
Abstract: The main route to nitrogen dioxide (NOz) formation in combustion systems is through the oxidation of nitric oxide (NO). This process was originally invcstigafed in order to explain the high proportion of NOz found in NOx emissions from the exhaust of gas turbine engines [l]. Moreover, the understanding of the NO-NO2 conversion mechanism is relevant to a number of issues including NOz emission from unflued space heaters, development of NOx control technologies, behavior of NO/N02 in the atmosphere, formation and reduction chemistry of NOx, and the probe sampling techniques for NOx concentration measurements. Originally, the NO-NO2 conversion was thought to proceed through the rapid oxidation of NO by oxidative radicals without much attention to the effect of fuels on the conversion [2-41. Although, in later studies, it was revealed that the conversion was greatly promoted by small quantities of fuels such as hydrocarbons, Hz, CO, and methanol [S-9]. In our former experiment and model calculation of the NO-NO2 conversion in the mixing of hot combustion gas with cold air and nine different fuels [6], the results indicated that NO-NO2 conversion appeared only in the low temperature range, and showed a strong dependence on fuel type. Thus, the interaction between the NO-NO2 reactions and the oxidation reactions of the fuel in the low temperature range must be .understood in order to explain the effect of fuel type on the NO-NO2 conversion and consequently to predict the NO/NO2 emission levels from combustion systems.

168 citations

Journal ArticleDOI
TL;DR: In this article, the ratio of formaldehyde columns to tropospheric nitrogen dioxide columns is an indicator of the relative sensitivity of surface ozone to emissions of nitrogen oxides (NO(x) = NO + NO2) and volatile organic compounds (VOCs).
Abstract: We present a novel capability in satellite remote sensing with implications for air pollution control strategy. We show that the ratio of formaldehyde columns to tropospheric nitrogen dioxide columns is an indicator of the relative sensitivity of surface ozone to emissions of nitrogen oxides (NO(x) = NO + NO2) and volatile organic compounds (VOCs). The diagnosis from these space-based observations is highly consistent with current understanding of surface ozone chemistry based on in situ observations. The satellite-derived ratios indicate that surface ozone is more sensitive to emissions of NO(x) than of VOCs throughout most continental regions of the Northern Hemisphere during summer. Exceptions include Los Angeles and industrial areas of Germany. A seasonal transition occurs in the fall when surface ozone becomes less sensitive to NOx and more sensitive to VOCs.

168 citations

Journal ArticleDOI
TL;DR: In this article, a series of Pt-Ba/Al2O3 NOx storage-reduction (NSR) catalysts having different Ba loadings (in the range 0-30%, w/w) have been prepared, characterized and tested in the NOx adsorption-Reduction under realistic operating conditions.

167 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