Showing results for: NO/NO2 Articles
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Advanced monitoring method for air environment
The Ogawa Passive Sampler is one of the only known methods of passive simultaneous monitoring of more than two components in the air. The first advantage of Ogawa Sampler is to have two chambers with the same configuration where one can place two different kinds of collection filter pads. In the case of simultaneous collection of NO and NO2, The O2 collection filter foated with triethanolamine ...
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Inter-annual variation of ambient ammonia and related trace gases in Delhi, India
Abstract In this study, ambient NH3, NO, NO2, CO and SO2 were measured continuously from February, 2008, to December, 2016. The annual average mixing ratios (mole/mole) of NH3, NO, NO2, CO and SO2 were 17.8 ± 3.4 ppb; 21.2 ± 2.3 ppb, 18.1 ± 3.2 ppb; 1.7 ± 0.3 ppm and 2.0 ± 0.3 ppb, ...
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Design of a dual-bed catalyst system with microporous carbons and urea-supported mesoporous carbons for highly effective removal of NOx at room temperature
Abstract A dual-bed catalyst system is designed to remove NOx at room temperature, which consists of a microporous spherical activated carbon (SAC) layer and a urea-supported spherical mesoporous carbon (SMC) layer. The SAC layer, with plenty of narrow micropores acting as a nano-cage for NO adsorption, could improve the oxidation of NO into NO2, while the urea-supported SMC layer with large ...
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High NOx Emissions from Diesel Cars
It is time to sell your diesel car. In a few years you will not be able to use it in a city. The real drive emissions measurements from passenger cars are giving astonishing results. A new diesel car has 10 times higher NOx emissions compared to a petrol car. Even worse, the NOx emitted from the diesel car is up to 50% emitted as NO2. The NOx emitted from a petrol car is only a few % emitted ...
By OPSIS AB
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Continuous monitoring of the performance of a NOx reduction system using electrochemical sensors
Abstract The efficiency of a NOx removal system is continuously measured using a TüVapproved analyser coupled to a high-temperature sampling system. Both NO and NO2 are measured directly using electrochemical sensors without the need to convert NO2 to NO. It is important to measure both components separately since the ratio of NO to NO2 in stack gas is much smaller after NOx removal. The ...
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A simple and practical model for reactive plumes
Pollutants emitted from industrial stacks can be transformed by chemical reactions. An interesting case is the NO to NO2 conversion due to reactions with the ambient ozone. A simple and practical model has been developed to calculate this conversion in the vicinity of the source. Spatial distributions of the reactive species concentrations in the plume are represented by generalised Gaussian ...
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Applying model calculations to estimate urban air quality with respect to the requirements of the EU directives on NO2, PM10 and C6H
Population exposure for NO2, PM10 and C6H6 for two Norwegian cities has been estimated for the year 2001. Calculated exposure levels have been related to the EU Council Directive limit levels of air quality. A stationary population distribution has been applied in the exposure calculations and a ranking of the most important sources contributing to the exceedances has been established. Results ...
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Measurement of ambient NH₃ over Bay of Bengal during W_ICARB campaign
Abstract Concentrations of ambient NH3, NO, NO2 and SO2 were measured over Bay of Bengal (BoB) during 28 December 2008 to 25 January 2009 to study their diurnal variation and relationship of NH3 with other trace gases over BoB. The measurements were done under the winter phase of Integrated Campaign on Aerosols and Radiation Budget (W_ICARB). For the first time, ambient NH3 was monitored ...
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BLUE LIGHT CONVERTER SIGNALS WAY FORWARD FOR NO2 MEASUREMENT
Local authorities seeking more accurate NO2 readings should consider using analysers which incorporate ‘Blue Light Converters’ says air quality monitoring specialists Enviro Technology. This comment comes following a presentation held at the Royal Society of Chemistry / AAMG Conference in December 2010 by EMPA (Switzerland) – an independent research and services institution ...
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Catalytic NO oxidation in the presence of moisture using porous polymers and activated carbon
Abstract NO oxidation catalyzed by porous materials is difficult to implement under industrial conditions because moisture in combustion exhaust streams blocks oxidation sites, decreasing NO conversion. In this work, hydrophobic cross-linked polymers are tested as NO oxidation catalysts to overcome these negative impacts associated with moisture. Although activated carbons (ACs) outperform ...
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Modeling Tip: Using Ozone File Editor Tools in BREEZE AERMOD
To model 1-hour and annual concentrations of NO2 for the National Ambient Air Quality Standard (NAAQS), the U.S. EPA has approved a three-tiered approach as detailed in Section 5.2.4 of EPA’s Guideline on Air Quality Models, Appendix W to 40 CFR Part 511 (Appendix W). This approach, as shown below, is recommended to estimate the ambient concentrations of NO2: Tier 1: Assume complete ...
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Tri-NOx Multi-Chem Wet Scrubber. Case Study of Our NOx Scrubber in a Hydroprocessing Plant.
Criterion Catalyst Co. L.P. is the world's largest supplier of catalysts for hydroprocessing, including hydrotreating applications. The company is also a leading supplier of reforming and specialty catalysts for the refining industry. Criterion's facility in Azusa, CA installed a Tri-NOx Mult-Chem scrubber with a 3000 cfm capacity at 250 lbs./hr. of NOx. The system has four polypropylene ...
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Pharmaceutical Manufacturer Turns NOx Regulations Into an Opportunity – With a 6-Figure Annual Chemical Savings as a Bonus.
This project was for a major manufacturer of a tabletted OTC analgesic. The manufacturing process was being redesigned, and a critical aspect of the work was the re-engineering of a reactor in the initial stage of manufacturing. The client’s original process, which used nitric acid to dissolve a metal, exhausted virtually 100% nitrogen oxide (NO), a toxic, wholly non-water-soluble gas that ...
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Objective evaluation of statistical models for next day ozone forecasting
Different stochastic auto-regressive non-stationary models with exogenous inputs have been identified and validated in order to predict maximum ozone concentration expected for the next day. Selected inputs were one-day forecasted meteorological variables and average concentrations of ozone precursors (compounds involved in ozone formation chemical reactions, i.e. NO, NO2, NMVOC). The model ...
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Wet NOx scrubber - Case study
This project was for a major manufacturer of a tableted OTC analgesic. The manufacturing process was being redesigned, and a critical aspect of the work was the re-engineering of a reactor. The client’s original process, which used nitric acid to dissolve a metal, exhausted virtually 100% nitrogen oxide (NO), a gas that reacts with oxygen to form a brown plume at concentrations as low as ...
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Nitrogen Oxides Reactions in Diesel Oxidation Catalyst
ABSTRACT Two catalyst formulations were tested OII a diesel engine. A Fourier Transform Infrared (FTIR) analyzer was used to measure concentrations of nitric oxide (NO) and nitrogen dioxide (NO2). Other exhaust gas components were measuredby conventional analyzers. The results indicate that nitrogen oxides (NO,) undergo complex chemical reactions in the diesel oxidation catalyst (DOC). The ...
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Data assimilation within the Air4EU project: the Athens case
The current study aims to investigate the application of the Data Assimilation (DA) in the greater Athens basin, according to the methodology developed within the framework of the Air4EU project. The advanced Sequential Importance Re-sampling (SIR) method was applied in an effort to improve the performance of the regional scale model OFIS. The current study was focused on the concentration levels ...
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Elevated PM10 concentrations and high PM2.5/PM10 ratio in the Brussels Urban area during the 2006 car-free Sunday
The results of the Car-Free Sundays in Brussels demonstrate the close relationship between the traffic and the presence of the gaseous pollutants such as NO, NO2, CO, CO2 and O3 in a traffic environment. The relationship with PM10 and PM2.5 seems to be much more complex. In fact, the PM10 and PM2.5 concentrations on the Car-Free Sunday 2006 were amongst the highest that year and they were three ...
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Dynamics of nitrogen oxides emission from a full-scale sludge liquor treatment plant with nitritation
Biological treatment in wastewater treatment plants (WWTPs) is a source of nitrogen oxides (N2O, NO and NO2) emitted to the atmosphere. Aerobic ammonia-oxidising bacteria (AOB) have been suggested to be the main source of these emissions. In a full-scale sludge liquor treatment plant at Sjölunda WWTP, it was shown that significant emissions of N2O, NO and NO2 do occur. The plant is operated with ...
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Seasonal Differences in the Origin of Nitrous Acid at Ashdod, Israel.
Abstract Measurements of Nitrous Acid (HONO) mixing ratios and other compounds were made in the north-east periphery of the town of Ashdod (south of Tel Aviv, Israel) during two campaigns in the autumn of 2004 and the summer of 2005. This work was part of a bilateral Italian-Israeli cooperation on environmental technologies, project “Modeling system for urban air pollution”. Statistical analysis ...
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