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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 Apr 1990-Nature
TL;DR: In this article, the authors used a global tropospheric model to simulate the chemistry of the pre-industrial atmosphere and that of the present day to estimate the surface ozone concentrations in the preindustrial atmosphere.
Abstract: THERE is evidence from records of ground-level measurements1–6 that the average tropospheric concentration of ozone in the Northern Hemisphere has increased. In particular, the comparison of recent observations with those made at the Montsouris laboratory in Paris between 1876 and 19105,6, suggests that the surface concentration of ozone at mid to high latitudes has more than doubled in the past 100 years. This has potential implications for a wide range of environmental issues both because of the direct effects of elevated concentrations of ozone on man and ecosystems7,8 and because ozone is a radiatively active gas which could contribute significantly to global warming if its concentration were to increase9–12. We have used a global tropospheric model to simulate the chemistry of the pre-industrial atmosphere and that of the present day. The model results for surface ozone concentrations in the pre-industrial atmosphere agree well with the Montsouris data, and the calculated concentrations for the present day agree with recent observations of a wide range of chemical species. Estimates of the future growth in emissions of nitrogen oxides (NOx) (ref. 13) have been used to make similar calculations for the year 2020. On the basis of these estimates, the global tropospheric concentration of ozone will continue to increase at a rate faster than during the past 100 years. The potential for further increases in tropospheric ozone needs to be taken into account when assessing the impact of air pollution emissions and the adequacy of measures to control them.

206 citations

Journal ArticleDOI
TL;DR: In this paper, online instruments were used to simultaneously monitor ozone, nitrogen oxides (NOx) and volatile organic compounds (VOCs) at GPACS (the Guangzhou Panyu Atmospheric Composition Station) of the China Meteorological Administration, from June 2011 to May 2012, in order to determine their characteristics, the effect of VOCs on ozone photochemical production and the relationship between VOC / NOx ratio and ozone formation.
Abstract: . Guangzhou, one of China's megacities, is beset with frequent occurrence of high-concentration ozone events. In this study, online instruments were used to simultaneously monitor ozone, nitrogen oxides (NOx) and volatile organic compounds (VOCs) at GPACS (the Guangzhou Panyu Atmospheric Composition Station) of the China Meteorological Administration, from June 2011 to May 2012, in order to determine their characteristics, the effect of VOCs on ozone photochemical production and the relationship between VOC / NOx ratio and ozone formation. The results showed that during the observation period, the seasonal variation of ozone concentration was lower in spring and winter compared to summer and autumn, which is opposite that for VOCs and NOx. In terms of VOCs, aromatics had the largest ozone formation potential, among which toluene, xylenes, ethylbenzene, 1,2,4-trimethylbenzene and 1,3,5-trimethylbenzene were the most important species, with a total contribution of about 44%. As the VOC / NOx ratios were very high during high-concentration ozone events that occur all year round, we speculate ozone production was likely to be NOx-limited regime (12:00–16:00 LT) in Guangzhou. Further investigation based on numerical models is needed in the future to obtain more detailed and robust conclusions.

206 citations

Journal ArticleDOI
TL;DR: A series of m-xylene/NOx experiments were conducted in the new Bourns College of Engineering-Center for Environmental Research and Technology dual 90 m3 indoor smog chamber to elucidate the role of NOx on the secondary organic aerosol (SOA) formation potential of m.xylene.
Abstract: A series of m-xylene/NOx experiments were conducted in the new Bourns College of EngineeringCenter for Environmental Research and Technology dual 90 m3 indoor smog chamber to elucidate the role of NOx on the secondary organic aerosol (SOA) formation potential of m-xylene The results presented herein demonstrate a clear dependence of m-xylene SOA formation potential on NOx, particularly at atmospherically relevant organic aerosol concentration Experiments with lower NOx levels generated considerably more organic aerosol mass than did experiments with higher NOx levels when reacted m-xylene was held constant For example, SOA formation from approximately 150 μg m-3 reacted m-xylene produced 06−93 μg m-3 aerosol mass for NOx concentrations ranging from 286 to 10 ppb The increase in SOA formation was not attributable to changes in ozone and nitrate concentration A general discussion about possible influences of NOx on SOA formation for this system is included

206 citations

Journal ArticleDOI
TL;DR: In this article, the effects of spray impingement, injection parameters, and exhaust gas recirculation (EGR) on the combustion characteristics and exhaust emissions of a premixed charge compression ignition (PCCI) diesel engine were investigated using a single-cylinder test engine and an optically accessible engine.

205 citations

Journal ArticleDOI
TL;DR: The relative incremental reactivity (RIR) results demonstrate that anthropogenic VOCs reduction is the most efficient way to mitigate ozone pollution at all sites, of which alkenes dominate >50% of the ozone production.

204 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