Determination Of Nitrogen Dioxide Research Articles

Calibration of a passive sampling device for the determination of nitrogen dioxide in ambient air

Nitrogen dioxide (NO2), a common air pollutant, has been widely admitted to be harmful to both the environment and human health, demanding its well-control procedure and corresponding quantification. In this study, NO2 in ambient air was collected by a passive sampling method using the Willems badge diffusive sampler, followed by a derivatization step with the Griess-Saltzman solution, and analyzed by ultraviolet-visible (UV–vis) spectroscopy at 543 nm. The device can be utilized for 168 h of continuous field sampling. The experimental sampling rate (Ke) of (4.02 ± 0.29) × 10−3 m3h−1 with a relative standard deviation (% RSD) of 9.6 % was determined by conducting parallel experiments between an active sampling method (ISO 6768:1998) and the Willems samplers. After exposure time, samplers could be stored for two weeks in a refrigerator at 4 °C before analyzing. The studied passive diffusive sampler was simple, low-cost, easy to reuse; permitted determining the average concentration of NO2 in ambient air. The average NO2 concentrations for 2-hour to 4-hour sampling periods at different studied sampling sites in Ho Chi Minh city (Vietnam) were ranged from 11.5 to 189 μg m−3.

Impurity Analysis of 5.5 N Nitrogen Gas and Its Impact on the Preparation of Class I Type Calibration Gas Mixtures

AbstractKnowledge of impurities in matrix gas is one of the critical requirements for the preparation of class I type calibration gas mixtures (primary reference gas mixtures, PRGMs) as per ISO 6142‐1. PRGMs are prepared gravimetrically using high‐purity component gas and high‐grade nitrogen, here 99.9995 % (5.5 N) as matrix gas. In this study, quantification of gaseous impurities such as moisture (H2O), methane (CH4), and carbon monoxide (CO) in 5.5 N nitrogen is performed using CRDS (cavity ring down spectroscopy). Carbon dioxide (CO2) and total hydrocarbons (THC) are analyzed using gas chromatography flame ionization detector (GC‐FID), while the determination of nitrogen dioxide (NO2) impurity is conducted colorimetrically using a UV‐Vis spectrophotometer. Total impurities in 5.5 N nitrogen are found to be (2945±21.5) ppb. The impact of utilizing this nitrogen is examined through the stability study of ambient range binary component gas mixtures of CH4 and CO in nitrogen and found that 5.5 N nitrogen can be used as matrix gas for preparing PRGMs of CH4 and CO. However, the component gas impurity present in nitrogen potentially affect the accuracy of gravimetrically prepared gas mixture.

Simplified procedures for evaluation of passive samplers for determination of nitrogen dioxide

Simplified procedures based on photometric and colorimetric detection have been developed and investigated for the determination of nitrite formed in passive sampling of NO2 with triethanolamine as sorptive medium. All procedures basically rely on the common Griess-Ilosvay reaction, but the experimental conditions are different. The variants evaluated are the application of liquid and solid reagents for photometric detection and a commercially available colorimetric test using a sliding color comparator. Furthermore, nitrite test strips were investigated. It was shown that solid reagent addition not only simplifies the analytical procedure but can provide higher sensitivity of the photometric assay. Colorimetric tests are inherently semi-quantitative, but results obtained - considering this restriction - were reliable and have the potential for fast determinations and at-site screening purposes. For the detection of nitrite in combination with passive sampling of NO2 they are attractive for low-budget educational purposes and citizen science projects and can serve for indicative monitoring. As an alternative to common spectrophotometers, an innovative LED-based photometer with WLAN/WIFI interface for smartphone-based data evaluation was investigated as a cheap and mobile-applicable detector for nitrite. Also reported is the development and application of a low-cost purpose-made reflectometer for evaluation of nitrite test strips. The color sensor module of the reflectometer - with light emitted from an inherent white LED - converts the reflected light from the test zone of the strips into RGB values. The relative intensity changes of the green color (complementary to the pink product of the Griess-Ilosvay reaction) can be correlated to the nitrite concentration of the sample solutions enabling improved concentration resolution of test strips compared with visual inspection. Ambient air measurements of NO2 were made and results obtainedof the analytical variants evaluated.

A Simple Technique Based on Digital Images for Determination of Nitrogen Dioxide in Ambient Air.

The lockdown to prevent the coronavirus spread resulted in an immediate reduction in gas concentration worldwide. This fact shows the importance of nitrogen dioxide as a pollutant gas directly associated with human activities. For indoor exposure, NO2 has been associated with effects on the respiratory system. In outdoor environments, ozone reaches a maximum after NO2 peaks, and acid rain arises with NO2 oxidation to forms nitric acid. Therefore, monitoring the NO2 concentration in atmospheric air can help prevent respiratory diseases and lower the concentration of other atmospheric pollutants. The experiment proposed in this article uses a low-cost passive sampler for the NO2 collection. An innovative and straightforward technique to determine the gas concentration through a gel-dyed formation and based on digital image analysis RGB colors channel are split by the software ImageJ. Results of digital image analysis and spectrophotometry were statistically agreed at a 95% confidence level. The advantages of the technique include low cost, the ready availability of components, ease of use, and sensitivity. The achievable resolution of nitrogen dioxide concentrations is 9 ppb for 24-h sampling.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11270-021-05031-4.

Performance evaluation of a new three-in one diffusive sampler for monitoring NO2, SO2 and O3

A tailor-made diffusive sampler has been developed for the determination of nitrogen dioxide (NO2), sulfur dioxide (SO2) and ozone (O3) concentrations with a performance evaluation of the sampler being carried out under field and laboratory conditions. The most important characteristics of the sampler design is that simultaneous sampling of the three pollutants can be performed in one sampler. All the parts of the diffusive sampler are reusable after cleaning. These properties provide important advantages in terms of cost and practicality. Two alternative samplers, having long and short diffusion paths, have been designed. Extensive validation studies, including detection limit, precision, accuracy, recovery, shelf life, storage stability, comparison with commercial diffusive samplers, and the effects of shelter use were conducted in accordance with European Standards (EN). According to the validation results, all of the parameters evaluated for the diffusive sampler (for both long and short diffusion path designs) comply with the related standards and the sampler is expected to play an important role in the widespread monitoring of inorganic pollutants, since it is cheap, easy to use and deliverable within the country.

Determination of Nitrogen Dioxide by Thin-Film Chemical Sensors Based on CdxPb1 –xS

The results of a study of sensors based on thin semiconductor films of CdxPb1 – xS solid solutions intended for the determination of nitrogen dioxide in air are described. For a comparative assessment of the composition, morphology, and functional properties of the films, they were synthesized from reaction mixtures containing various cadmium salts. It was found that the maximum response is provided by layers obtained using cadmium acetate, in which the composition of the solid solution differs in the maximum supersaturation level in CdS. The films were formed of crystallites with average sizes of ~200 nm. When the concentration of nitrogen dioxide in air was 0.05‒200 mg/m3, the relative change in the ohmic resistance of sensors ranged from 8 to 80%. It was shown that the threshold concentration of NO2 in air was about 0.02 mg/m3. The reversible nature of the gas adsorption process opens a possibility for the creation of reusable chemical sensors based on CdxPb1 – xS films, differing in a relatively low threshold concentration of NO2 detection and selective response in the presence of significantly higher concentrations of O2, CO2, and H2.

Toxic gases removal onto activated carbons obtained from hay with the use of microwave radiation

A technology for obtaining activated carbons by physical activation of hay with the use of microwave radiation is described. The effect of pyrolysis temperature on the textural parameters, acid–base character of the surface and sorption properties of activated carbons has been tested. The sorption properties of the activated carbons obtained were characterized by determination of nitrogen dioxide and hydrogen sulphide adsorption in dry and wet conditions. The final products were adsorbents of surface area ranging from 196 to 377m2/g and pore volume from 0.14 to 0.24cm3/g, showing basic character of the surface. The results obtained in our study have proved that suitable choice of the pyrolysis and activation procedure for hay with the use of microwave radiation permits production of adsorbents with good capacity toward toxic gases of acidic character.

The use of microwave radiation for obtaining carbonaceous adsorbents from biomass and their use in elimination of inorganic pollutants

A new technology of obtaining activated carbons by physical and direct activation of biomass with the use of microwave radiation is described. The effect of activation temperature (700 and 800 °C) and two periods of time (15 and 30 min) on the textural parameters, acid–base character of the surface and sorption properties of activated carbons was tested. The resulting carbons were characterized by low-temperature nitrogen sorption and determination of pH as well as the number of surface oxygen groups. The sorption properties of the activated carbons obtained were characterized by determination of nitrogen dioxide and hydrogen sulphide adsorption in dry and wet conditions as well as by iodine removal from aqueous solution. The final products were adsorbents of surface area ranging from 291 to 368 m2/g and pore volume from 0.20 to 0.26 cm3/g, showing basic character of the surface. The results obtained in our study have proved that suitable choice of the pyrolysis and activation procedure for hay with the use of microwave radiation permit producing adsorbents with good capacity toward toxic gases of acidic character as well as inorganic pollutants of molecules of size similar to that of iodine molecules.

Visualizing gaseous nitrogen dioxide by ratiometric fluorescence of carbon nanodots-quantum dots hybrid.

A novel nanohybrid ratiometric fluorescence probe for on-site and visual determination of nitrogen dioxide (NO2) has been designed. The hybrid probe comprises blue-colored fluorescence carbon nanodots (CDs) and red-colored emission CdTe quantum dots (QDs). Such hybridized probe exhibits dual emission bands centered at 460 and 665 nm, respectively. The blue fluorescence of CDs is insensitive to the analyte, whereas the red emission of QDs is specifically quenched by the analyte, resulting in a distinguishable color change from orange-red to blue upon exposure to NO2. The limit of detection for nitrogen dioxide is estimated to be 19 nM in aqueous solution. More importantly, the nanohybrid probe has been successfully applied in visual detection of gaseous NO2 with a detection limit of 1 ppm, suggesting its potential application for NO2 sensing.

Sorption properties of activated carbons obtained from corn cobs by chemical and physical activation

The paper presents results of a study on obtaining activated carbon from common corn cobs and on its use as adsorbent for removal of pollution from liquid and gas phases. The crushed precursor was subjected to pyrolysis at 500 and 800 °C in argon atmosphere and next to physical or chemical activation by CO2 and KOH respectively. The effect of pyrolysis conditions and activation method on the physicochemical properties of the materials obtained was tested. The sorption properties of the carbonaceous adsorbents obtained were characterized by determination of nitrogen dioxide and hydrogen sulphide sorption from gas stream in dry and wet conditions as well as by iodine and methylene blue removal from aqueous solution. The final products were microporous activated carbons of well-developed surface area varying from 337 to 1213 m2/g and showing diverse acid-base character of the surface. The results obtained in our study have proved that a suitable choice of the activation procedure for corn cobs permits production of cheap adsorbents with high sorption capacity toward toxic gases of acidic character as well as different pollutants from liquid phase.

Physical Examination of Method for the Determination of Nitrogen Dioxide in the Atmosphere by using Triethanolamine Filter Paper, and Few Applications of Method.

Physical Examination of Method for the Determination of Nitrogen Dioxide in the Atmosphere by using Triethanolamine Filter Paper, and Few Applications of Method.

Method for the Determination of Nitrogen Dioxide, Sulfur Dioxide and Formaldehyde in the Atmosphere by using Triethanolamine Filter Paper

Method for the Determination of Nitrogen Dioxide, Sulfur Dioxide and Formaldehyde in the Atmosphere by using Triethanolamine Filter Paper

On the improvement of NO<sub>2</sub> satellite retrievals – aerosol impact on the airmass factors

Abstract. The accurate determination of nitrogen dioxide (NO2) tropospheric vertical columns from satellite measurements depends strongly on the airmass factor (AMF) used. A sensitivity study was performed with the radiative transfer model SCIATRAN to better understand the impact of aerosols on the calculation of NO2 AMFs. This influence was studied by varying the NO2 and aerosol vertical distributions, as well as physical and optical properties of the particles. In terms of aerosol definitions, the key factors for these calculations were identified as the relation between trace gas and aerosol vertical profiles, the optical depth of the aerosol layer, and single scattering albedo. In addition, surface albedo also has a large impact on the calculations. Overall it was found that particles mixed with the trace gas increases the measurements' sensitivity, but only when the aerosol is not very absorbing. The largest change, a factor of ~2 relative to the situation without aerosols, was found when a low layer of aerosol (600 m) was combined with a homogenous NO2 layer of 1.0 km. A layer of aerosol above the NO2 usually reduces the sensitivity of the satellite measurement. This situation is found mostly for runs with discrete elevated aerosol layers (representative for long-range transport) that can generate a decrease of the AMF values of up to 70%. The use of measured aerosol profiles and modelled NO2 resulted, generally, in much smaller changes of AMF relative to the pure Rayleigh case. Exceptions are some events of elevated layers with high aerosol optical depth that lead to a strong decrease of the AMF values. These results highlight the importance of aerosols in the retrieval of tropospheric NO2 columns from space and indicate the need for detailed information on aerosol properties and vertical distribution.

A sensitive spectrophotometric determination of nitrogen dioxide in the working atmosphere

In the present investigation, a simple and sensitive spectrophotometric method for the determination of nitrogen dioxide in various environmental samples is described. Nitrogen dioxide in air was fixed as nitrite ion in alkaline sodium arsenite absorbing solution. The nitrite formed was diazotized with paminoacetophenone in acidic medium which was subsequently coupled with phloroglucinol to give yellow-orange dye in alkaline medium having an absorption maximum at 420 nm. Beer’s law was obeyed in the range of 0.008 - 0.12 μg mL-1 of nitrogen dioxide and has a molar absorptivity of 2.875 x 105 L mol-1 cm-1. Optimum reaction conditions for diazotization, full colour development and the effect of variables like temperature, time and pH have been studied. Detailed studies to check the collection efficiency and NO2:NO2 - stoichiometric ratio has beencarried out. The reaction has been successfully applied for the detection of nitrogen dioxide in cigarette smoke, scooter exhaust, and workroom air.

Determination of nitrogen dioxide, sulfur dioxide, ozone, and ammonia in ambient air using the passive sampling method associated with ion chromatographic and potentiometric analyses.

Concentrations of nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), and ammonia (NH3) were determined in the ambient air of Al-Ain city over a year using the passive sampling method associated with ion chromatographic and potentiometric detections. IVL samplers were used for collecting nitrogen and sulfur dioxides whereas Ogawa samplers were used for collecting ozone and ammonia. Five sites representing the industrial, traffic, commercial, residential, and background regions of the city were monitored in the course of this investigation. Year average concentrations of ≤59.26, 15.15, 17.03, and 11.88 μg/m3 were obtained for NO2, SO2, O3, and NH3, respectively. These values are lower than the maxima recommended for ambient air quality standards by the local environmental agency and the world health organization. Results obtained were correlated with the three meteorological parameters: humidity, wind speed, and temperature recorded during the same period of time using the paired t test, probability p values, and correlation coefficients. Humidity and wind speed showed insignificant effects on NO2, SO2, O3, and NH3 concentrations at 95% confidence level. Temperature showed insignificant effects on the concentrations of NO2 and NH3 while significant effects on SO2 and O3 were observed. Nonlinear correlations (R 2 ≤ 0.722) were obtained for the changes in measured concentrations with changes in the three meteorological parameters. Passive samplers were shown to be not only precise (RSD ≤ 13.57) but also of low cost, low technical demand, and expediency in monitoring different locations.

The determination of nitrogen dioxide in ambient air with free hanging filters as passive samplers, and a new calibration method using fritted bubblers

This paper describes two new methods for the determination of NO(2) in the ambient air. The first method consists of free hanging filters with a diameter of 2.5 cm as passive samplers. The filters are impregnated with triethanolamine to bind NO(2). With standard colorimetrical analysis, the amount of NO(2) on the filters is determined. The second method is performed with fritted bubblers filled with Saltzman reagent, where, with a special procedure the absorption efficiencies of the bubblers are determined using ambient air, without the use of standard gases and electronic analytical instruments. The results of the bubblers are used to calibrate the free hanging filters. The two methods were applied simultaneously in the city of Yogyakarta, Indonesia. The methods are inexpensive and very well suited for use in low-budget situations. A characteristic of the free filter is the Sampling Volume, SV. This is the ratio of the amount of NO(2) on the filter and the ambient concentration. With the filter used in this study, the amount of triethanolamine and exposure time, the SV is 0.0166 m(3). The sampling rate (SR) of the filter, 4.6 cm(3)/s, is high. Hourly averaged measurements are performed for 15 hours per day in four busy streets. The measured amounts of NO(2) on the filters varied between 0.57 and 2.02 microg NO(2), at ambient air concentrations of 32 to 141 microg/m(3) NO(2). During the experiments the wind velocity was between 0.2 and 2.0 m/s, the relative humidity between 24 and 83 % and the temperature between 295 K and 311 K. These variations in weather conditions have no influence on the uptake of NO(2).

Determination of nitrogen dioxide in ambient air employing diffuse reflectance Fourier transform infrared spectroscopy

This paper presents the development of a simple and precise analytical method for the determination of nitrogen dioxide in ambient air. In this method nitrogen dioxide is determined in the form of nitrite. The determination of nitrogen dioxide needs no reagents except for a solution of sodium hydroxide mixed with sodium arsenite (NaOH–Na 2As 2O 3) which is used as an absorbing reagent for trapping the nitrogen dioxide from the atmosphere in the form of nitrite, i.e., a prior analysis step. The determination of submicrogram levels of nitrogen dioxide is based on the selection of a strong and sharp quantitative analytical peak at 1380 cm − 1 using diffuse reflectance infrared spectroscopy (DRS-FTIR). The limit of detection (LOD) and the limit of quantification of the method are found to be 0.008 μg g − 1 NO 2 − and 0.05 μg g − 1 NO 2 −, respectively. The precision in terms of standard deviation and relative standard deviation value at a level of 2 μg NO 2 − / 0.1 g KBr for n = 10 is found to be 0.036 μg NO 2 − and 1.8%, respectively. The relative standard deviation ( n = 10) for the determination of nitrogen dioxide in ambient air was observed to be in the range 2.6–3.8%. The method proposed is time-saving and eliminates the slow and cumbersome steps of pH maintenance of the reaction mixture and color formation of the EPA recommended spectrophotometric and other methods for quantitative determination of nitrogen dioxide.

Aminophenyl Benzimidazole as a New Reagent for the Estimation of NO2/Nitrite/Nitrate at Trace Level: Application to Environmental Samples

A simple and sensitive spectrophotometric method for the determination of nitrogen dioxide in ambient air and nitrite/nitrate in water and soil samples has been developed. Nitrogen dioxide in air has been fixed as nitrite ion using alkaline sodium arsenite as absorbing medium. The method is based on the reaction of nitrite with aminophenyl benzimidazole in acid medium to form diazonium ion, which is coupled with N‐(1‐naphthyl)ethylenediamine dihydrochloride to form an azo dye with an absorption maximum at 555 nm in aqueous phase. The method obeys Beer's law in the concentration range 0–10 µg of nitrite in 25 ml solution. The molar absorptivity has been found to be 6.3×104 l mol−1 cm−1. The dye can be extracted quantitatively into isoamyl alcohol under alkaline condition and the addition of methanolic hydrochloric acid restores the original dye colour. Beer's law is obeyed in the concentration range 0–2 µg of nitrite with a detection limit of 0.009 µg. The effect of interfering species has been studied and the developed method has been applied to determine trace levels of nitrogen dioxide in ambient air and the results have been compared with the standard method. It is also applied to measure the nitrite/nitrate levels of surface and ground water samples collected from lakes, tube wells as well as soil samples.

A Passive Sampler for Determination of Nitrogen Dioxide in Ambient Air

This article describes the use of a passive sampler for detecting and collecting nitrogen dioxide, NO2, in ambient air. This device is based on microporous PTFE membranes that allow air samples to ...

Droplet Method for the Determination of Nitrogen Dioxide in Atmosphere

Droplet Method for the Determination of Nitrogen Dioxide in Atmosphere