Non-dispersive Infrared Method Research Articles

Research Progress on End-Tidal Carbon Dioxide Detection Technology Based on Non-Dispersive Infrared Method

The concentration of end-tidal carbon dioxide is one of the important indicators for evaluating whether the human respiratory system is normal. Accurately detecting of end-tidal carbon dioxide is of great significance in clinical practice. With the continuous promotion of the localization of end-tidal carbon dioxide monitoring technology, its application in clinical practice in China has become increasingly widespread in recent years. The study is based on the non-dispersive infrared method and comprehensively elaborates on the detection principle, gas sampling methods, key technologies, and technological progress of end-tidal carbon dioxide detection technology. It comprehensively introduces the current development status of this technology and provides reference for application promotion and further improvement.

A CO2 Concentration Detection Platform and Temperature Compensation Method Based on Zynq Series SoC

Aiming at the problem of low flexibility and poor scalability of Non-Dispersive InfraRed method CO2 concentration detection equipment, a CO2 concentration detection platform based on Zynq series SoC is designed. The platform adopts the idea of hardware-software co-design, which integrates the functions of signal acquisition, time domain filtering, mode control, and data integration, simplifying the hardware design and improving the functional scalability of the system. The platform completes the automatic calibration and temperature compensation and realizes the accurate real-time calculation of CO2 gas concentration. The detection error can be controlled within ±78 ppm in the temperature variation range of 10–60 °C and the measurement range of 0–5000 ppm. The platform is designed with high flexibility, good detection stability, small detection error, little influence by temperature, and strong scalability. It can be organically combined with artificial intelligence, intelligent sensing, and other technologies and has good application prospects.

Mitigating Indoor Risk of Airborne Infections: the MIRAI project

BACKGROUND AND AIM. The risk of infection from SARS-CoV-2 and other airborne diseases is known to be higher in indoor environment, also depending on personal (e.g. individual susceptibility, modality of exposure, viral load) and environmental (e.g. airflow, temperature, humidity) factors. Measurements of CO₂ indoors are often used as a proxy for air quality and recent evidence suggests that its monitoring can be helpful to identify poorly ventilated multi-occupancy spaces like offices and classrooms, thus possibly evaluating the risk of exposure to indoor airborne contaminants, including infectious agents. In addition, the recent availability of portable low-cost sensors has been suggested to be effective in the prevention of SARS-CoV-2 infection and other airborne diseases. METHODS. In this project, we will use low-cost sensors for the evaluation of CO₂ levels using Non-Dispersive InfraRed method. We will assess CO₂ levels in high school and university in Modena, Norther Italy from March 2022 up to end of the year. Information factsheets will be placed along with the sensors with detailed information about the project aim and purpose, guidelines for adequate CO₂ monitoring and alert thresholds (800 and 1400 ppm) indicating the need to increase the ventilation (e.g. opening doors and windows). Calibration and quality control of the low-cost monitors will be also performed to ensure the reliability of the measurements. RESULTS AND CONCLUSIONS. The monitoring campaign has started as planned and the environmental and health data collection is ongoing. Considering the recommendations to prevent SARS-CoV-2 in Italy still indicate to wear masks for both students and personnel as well as the lowering of pandemic spread, no positive cases have been identified within the monitored classrooms. Project results will be presented during the conference. Funded by grant "FAR 2021 Mission Oriented-Linea FOMO". Keywords. SARS-CoV-2; indoor air quality; CO₂ monitoring; low-cost sensors; risk assessment; prevention.

A miniature Portable Emissions Measurement System (PEMS) for real-driving monitoring of motorcycles

Abstract. We present an exploratory study carried out with a new miniature portable emission measurement system (Mini-PEMS) specifically designed at the Technical University of Liberec (CZ) for applications on two-wheeler vehicles owing to its reduced size (45cm×30×20cm) and weight (≈15 kg). It measures the exhaust gas concentrations of hydrocarbons and carbon mono- and dioxide with a nondispersive infrared method and nitrogen mono- and dioxides and oxygen using an electrochemical cell. In addition, the instrument acquires the engine speed, manifold absolute pressure, inlet and exhaust gas temperature, geo-localization, and vehicle speed. The exhaust mass flow rate is calculated from engine and emission data. The Mini-PEMS was validated on three two-wheelers (one moped and two motorcycles) against laboratory-grade instrumentation in the Vehicle Emissions Laboratory of the European Commission in terms of measured concentrations, exhaust flow, fuel consumption, and mass emission of pollutants. The mean absolute deviations of gas concentrations were 8 % for HC, 8 % for CO, 13 % for NOx, and 2 % for CO2, while the mass emissions (which include the exhaust flow determination uncertainty) were 7 % for HC, 7 % for CO, 9 % for NOx, and 5 % for CO2. An agreement of 2 % was achieved between the fuel consumption measured in the laboratory and calculated by the Mini-PEMS. As an application, the instrument was tested on board the vehicles during on-road trips. The emissions measured on the road were consistent among repeated runs, with differences between laboratory and on-road tests much larger than those between the Mini-PEMS and laboratory. We found similar or larger HC and NOx real-driving emissions and larger CO emissions from motorcycles and smaller ones for the moped. Considering its size and weight, the Mini-PEMS proved to be an efficient tool for vehicle monitoring, research and development and could be tested for in-service monitoring applications related to carbon monoxide and nitrogen oxides emissions. A tentative approach to characterize particulate mass and particle number was presented and compared to the existing filter method and nonvolatile particle number protocol.

Design of Automobile Exhaust Wireless Monitor System Based on GPRS/GSM/GPS

For the problem of automobile exhaust emission pollution is more and more serious, according to the basic principle of non-dispersive infrared method(NDIR), we design a new kind of automobile exhaust wireless monitoring system with the existing GPRS/GSM/GPS technology. This system uses the three-layer structure of car-terminal, wireless network and PC monitoring center. We introduce and research the key technologies and methods of realizing the system. This system has the advantages of convenience and quick, good real-time, easy to manage and etc.

A Study on CO<sub>2</sub>/CO Dual Sensor Module by NDIR Method

This research deals with the CO2/CO Dual Sensor Module measuring CO2 and CO, that is the representative environmental harmful material, simultaneously. In the measurement of the CO2and CO generally, the Non-Dispersive InfraRed method(NDIR method) is used for the precise measurement and durability. This method is to measure the concentration of the gas by using the Lambert-beer rule. When measuring the gas density with the NDIR method, the important factor is the apparatus for being called an optical chamber consisting of the emitter sensor and detector sensor are used for measuring concentration of the gas. Thus, this paper introduces an optical chamber of the new way of using the NDIR method and through this, shows an experimental result of the CO2gas concentration measurement and it presents possibility for measurement of the concentration of the CO.

Nitrous oxide emissions from gasohol, ethanol and CNG light duty vehicles

A sample of 21 light duty vehicles powered by Otto cycle engines were tested on a chassis dynamometer to measure the exhaust emissions of nitrous oxide (N2O). The tests were performed at the Vehicle Emission Laboratory of CETESB (Environmental Company of the State of Sao Paulo) using the US-FTP-75 (Federal Test Procedure) driving cycle. The sample tested included passenger cars running on three types of fuels used in Brazil: gasohol, ethanol and CNG. The measurement of N2O was made using two methods: Non Dispersive InfraRed (NDIR) analyzer and Fourier Transform InfraRed spectroscopy (FTIR). Measurements of regulated pollutants were also made in order to establish correlations between N2O and NOx. The average N2O emission factors obtained by the NDIR method was 78 ± 41 mg.km−1 for vehicles running with gasohol, 73 ± 45 mg.km−1 for ethanol vehicles and 171 ± 69 mg.km−1 for CNG vehicles. Seventeen results using the FTIR method were also obtained. For gasohol vehicles the results showed a good agreement between the two methods, with an average emission factor of 68 ± 41 mg.km−1. The FTIR measurement results of N2O for ethanol and CNG vehicles were much lower than those obtained by the NDIR method. The emission factors were 17 ± 10 mg.km−1 and 33 ± 17 mg.km−1, respectively, possibly because of the interference of water vapor (present at a higher concentration in the exhaust gases of these vehicles) on measurements by the NDIR method.

Research of the examination method of ET-CO2 based on high speed operation chip ADμC7026

Objective To develop one kind of mainstream ET-CO2 (carbon dioxide of the expiration tip)detector which provides accurate and real-time testing results. Methods Applying ADμC7026 as central processing unit for data pre-processing, temperature compensation algorithm and non-linear correction, the ETCO2 concentration, respiration waveform and respiration rate were obtained. Results The analyzing results of the experimental data shows that the system meets the design requirements with fine stability, rapid response, good repeatability and high accuracy. Conclusion ET-CO2 detector based on ADμC7026 makes the detection of CO2 more accurate and reliable, which provides more accurate real-time data for critical patient monitoring, anesthetic care, pediatric respiratory care and so on. Key words: Carbon dioxide of the expiration tip; Non-dispersive infrared method; Respiration rate; Temperature compensation

The characteristics of atmospheric CO2 concentration variation of four national background stations in China

Atmospheric carbon dioxide is an important kind of greenhouse gas which influences global temperature. Its concentration variation could indicate the distribution of human and natural activities in various regions. Through the non-dispersive infrared method, flask sampling of atmospheric CO2 concentration was measured weekly at four national background stations including Waliguan, Shangdianzi, Lin’an, and Longfengshan. Based on the data collected from September 2006 to August 2007, along with the Waliguan station’s experience on in situ observational data processing, the selection methods for sampling data through the atmospheric background CO2 concentration analysis were preliminarily discussed. On the basis of this result, the variation features of the four typical regions’ atmospheric background CO2 concentration was analyzed for the first time. The results show that the atmospheric CO2 concentration at Waliguan, Shangdianzi, Lin’an, and Longfengshan is 383.5, 385.9, 387.8, and 384.3 ppm, respectively. During the research period, CO2 concentration at the Waliguan station changed slightly. However, the CO2 concentration changed sharply at the Shangdianzi and the Lin’an stations due to the great influence of human activities in the Jingjinji and the Changjiang Delta economic zones, and changed regularly with seasons at Longfengshan station under dual influences of human activities and plant photosynthesis. The results from this study can lay the foundation for more profound studies on atmospheric CO2 concentration level of different areas in China, and could be used to improve the understanding of carbon source and sink distribution.

비분산 적외선 분광법을 이용한 Co2농도 고속 분석기의 Sampling Module 특성에 관한 실험적 연구

A fast response analyzer for measuring carbon dioxide concentration has been developed for transient characteristic and researches tested on internal combustion engine. The analyzer uses the well known NDIR(Non-Dispersive Infrared) method with miniaturized detection system, giving a time constant of approximately 30 microsecond, and sampling module consists of capillary tube. Since the transit time and the time constant of the sampling system depend on the sampling conditions, it is necessary to investigate the characteristics of sampling system before applied to exhaust gas measurement in engine. A unique method was designed to study the influence of the diameter of transfer sample line and operating conditions of the FRNDIR on transit time and time constant. A database of transit time and time constant was built up for different measured and simulated pressure conditions. The database can be used for correcting eventual concentration measurement.

Comparison of detector tube to NDIR for estimating carbon monoxide in atmosphere of urban streets

Nondispersive infrared method (NDIR) is one of the most reliable and accurate methods for the measurement of cffrbon monoxide (CO) concentration in urban air. Detector tube method is widely used for the same purpose as a field method because of its simplicity. Four types of detector tube (A, B, C and G) are available in the market and, in this paper, the obtained CO values by the four detector tubes were compared with NDIR results as the reference. Type B and C of the tube gave slightly larger values and type G gave values agreeing with NDIR. The type A tube gave remarkably higher results, which were due to, probably, the influence of hydrocarbons in the sample air.