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Zhang Q, Mou F, Li S, Li A, Wang X, Sun Y. Quantifying emission fluxes of atmospheric pollutants from mobile differential optical absorption spectroscopic (DOAS) observations. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 286:121959. [PMID: 36252302 DOI: 10.1016/j.saa.2022.121959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 09/20/2022] [Accepted: 10/05/2022] [Indexed: 06/16/2023]
Abstract
This study demonstrates a mobile passive differential optical absorption spectroscopy (DOAS) based remote sensing method for quantifying the emission fluxes of soot pollutants. First, the mobile DOAS system scans the plume emitted from urban sources. Then, the DOAS method retrieves the total columns of pollutant gases along the measurement path. Combining the longitude, latitude, and mobile speed recorded by vehicle GPS, the net emission fluxes of NO2 and SO2 in the measurement area are calculated by coupling with the wind field data. The NO2 flux in the region is combined with the NO to NO2 concentration ratio in the Copernicus Atmospheric Monitoring Service (CAMS) model to calculate NOx net emission flux in the measurement period. We conducted the mobile DOAS measurements in the coal production area and obtained the distribution of pollutant gases along the measurement path. Meanwhile, the NO2 concentration distribution of the city and surrounding areas were reconstructed by using TROPOMI satellite data. During the mobile measurement, the net NO2 emission flux measured by mobile DOAS are in good agreement with satellite observations (R2 = 0.66). This study verified that the flux calculation method based on mobile DOAS can be used to detect urban soot pollutant gas emissions.
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Affiliation(s)
- Qijin Zhang
- Department of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000, China
| | - Fusheng Mou
- Department of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000, China
| | - Suwen Li
- Department of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000, China.
| | - Ang Li
- Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| | - Xude Wang
- Department of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000, China
| | - Youwen Sun
- Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China.
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Roșu A, Constantin DE, Voiculescu M, Arseni M, Roșu B, Merlaud A, Van Roozendael M, Georgescu PL. Assessment of NO 2 Pollution Level during the COVID-19 Lockdown in a Romanian City. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:E544. [PMID: 33440815 PMCID: PMC7827512 DOI: 10.3390/ijerph18020544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 12/23/2020] [Accepted: 12/31/2020] [Indexed: 11/16/2022]
Abstract
This study investigates changes in pollution associated with the lockdown period caused by the COVID-19 pandemic in Galati (45.43° N, 28.03° E), a Romanian city located in the southeast of Romania. The study is focused on nitrogen dioxide (NO2), a trace gas which can be related to emissions from industrial activities, heating, and transportation. The investigation is based on in situ observations from local Air Quality Monitoring Stations (AQMS) and mobile remote sensing observations by Differential Optical Absorption Spectroscopy (DOAS) technique. We also show results of the NO2 vertical column measured by TROPOMI (TROPOspheric Monitoring Instrument), a space instrument onboard of satellite mission Sentinel-5P, to complement local ground-based measurements. For in situ observations, the lockdown interval (23 March 2020-15 May 2020) was separated from normal periods. The decrease in local NO2 concentration during lockdown, measured in situ, is rather small, of about 10-40% at the most, is observed only at some stations, and is better seen during workdays than during weekends. We conclude that the decrease in NO2 content over Galati city during lockdown is relatively small and may be attributed to the reduction in local traffic, a consequence of special measures and restrictions imposed during the COVID-19 lockdown by the Romanian authorities.
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Affiliation(s)
- Adrian Roșu
- Faculty of Sciences and Environment, The European Centre of Excellence for the Environment, “Dunarea de Jos” University of Galati, Domneasca Street, No. 111, 800201 Galati, Romania; (A.R.); (D.-E.C.); (M.A.); (B.R.); (P.L.G.)
| | - Daniel-Eduard Constantin
- Faculty of Sciences and Environment, The European Centre of Excellence for the Environment, “Dunarea de Jos” University of Galati, Domneasca Street, No. 111, 800201 Galati, Romania; (A.R.); (D.-E.C.); (M.A.); (B.R.); (P.L.G.)
| | - Mirela Voiculescu
- Faculty of Sciences and Environment, The European Centre of Excellence for the Environment, “Dunarea de Jos” University of Galati, Domneasca Street, No. 111, 800201 Galati, Romania; (A.R.); (D.-E.C.); (M.A.); (B.R.); (P.L.G.)
| | - Maxim Arseni
- Faculty of Sciences and Environment, The European Centre of Excellence for the Environment, “Dunarea de Jos” University of Galati, Domneasca Street, No. 111, 800201 Galati, Romania; (A.R.); (D.-E.C.); (M.A.); (B.R.); (P.L.G.)
| | - Bogdan Roșu
- Faculty of Sciences and Environment, The European Centre of Excellence for the Environment, “Dunarea de Jos” University of Galati, Domneasca Street, No. 111, 800201 Galati, Romania; (A.R.); (D.-E.C.); (M.A.); (B.R.); (P.L.G.)
| | - Alexis Merlaud
- Royal Belgian Institute for Space Aeronomy (BIRA-IASB), Ringlaan-3-Avenue Circulaire, B-1180 Brussels, Belgium; (A.M.); (M.V.R.)
| | - Michel Van Roozendael
- Royal Belgian Institute for Space Aeronomy (BIRA-IASB), Ringlaan-3-Avenue Circulaire, B-1180 Brussels, Belgium; (A.M.); (M.V.R.)
| | - Puiu Lucian Georgescu
- Faculty of Sciences and Environment, The European Centre of Excellence for the Environment, “Dunarea de Jos” University of Galati, Domneasca Street, No. 111, 800201 Galati, Romania; (A.R.); (D.-E.C.); (M.A.); (B.R.); (P.L.G.)
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NOx Emission Flux Measurements with Multiple Mobile-DOAS Instruments in Beijing. REMOTE SENSING 2020. [DOI: 10.3390/rs12162527] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
NOX (NOX = NO + NO2) emissions measurements in Beijing are of great significance because they can aid in understanding how NOX pollution develops in mega-cities throughout China. However, NOX emissions in mega-cities are difficult to measure due to changes in wind patterns and moving sources on roads during measurement. To obtain good spatial coverage on different ring roads in Beijing over a short amount of time, two mobile differential optical absorption spectroscopy (DOAS) instruments were used to measure NOX emission flux from April 18th to 26th, 2018. In addition, a wind profile radar provided simultaneous wind field measurements for altitudes between 50 m and 1 km for each ring road measurement. We first determined NOX emission flux of different ring roads using wind field averages from measured wind data. The results showed that the NOX emission flux of Beijing’s fifth ring road, which represented the urban part, varied from (19.29 ± 5.26) × 1024 molec./s to (36.46 ± 12.86) × 1024 molec./s. On April 20th, NOX emission flux for the third ring was slightly higher than the fourth ring because the two ring roads were measured at different time periods. We then analyzed the NOX emission flux error budget and error sensitivity. The main error source was the wind field uncertainty. For some measurements, the main emission flux error source was either wind speed uncertainty or wind direction uncertainty, but not both. As Beijing’s NOX emissions came from road vehicle exhaust, we found that emission flux error had a more diverse sensitivity to wind direction uncertainty, which improved our knowledge on this topic. The NOX emission flux error sensitivity study indicated that more accurate measurements of the wind field are crucial for effective NOX emission flux measurements in Chinese mega-cities. Obtaining actual time and high resolved wind measurements is an advantage for mega-cities’ NOX emission flux measurements. The emission flux errors caused by wind direction and wind speed uncertainties were clearly distinguished. Other sensitivity studies indicated that NOX/NO2 ratio uncertainty dominated flux errors when the NOX/NO2 ratio uncertainty was >0.4. Using two mobile-DOAS and wind profile radars to measure NOx emission flux improved the quality of the emission flux measuring results. This approach could be applied to many other mega-cities in China and in others countries.
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Mobile DOAS Observations of Tropospheric NO2 Using an UltraLight Trike and Flux Calculation. ATMOSPHERE 2017. [DOI: 10.3390/atmos8040078] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Emission Flux Measurement Error with a Mobile DOAS System and Application to NO x Flux Observations. SENSORS 2017; 17:s17020231. [PMID: 28125054 PMCID: PMC5336080 DOI: 10.3390/s17020231] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 01/18/2017] [Accepted: 01/19/2017] [Indexed: 12/02/2022]
Abstract
Mobile differential optical absorption spectroscopy (mobile DOAS) is an optical remote sensing method that can rapidly measure trace gas emission flux from air pollution sources (such as power plants, industrial areas, and cities) in real time. Generally, mobile DOAS is influenced by wind, drive velocity, and other factors, especially in the usage of wind field when the emission flux in a mobile DOAS system is observed. This paper presents a detailed error analysis and NOx emission with mobile DOAS system from a power plant in Shijiazhuang city, China. Comparison of the SO2 emission flux from mobile DOAS observations with continuous emission monitoring system (CEMS) under different drive speeds and wind fields revealed that the optimal drive velocity is 30–40 km/h, and the wind field at plume height is selected when mobile DOAS observations are performed. In addition, the total errors of SO2 and NO2 emissions with mobile DOAS measurements are 32% and 30%, respectively, combined with the analysis of the uncertainties of column density, wind field, and drive velocity. Furthermore, the NOx emission of 0.15 ± 0.06 kg/s from the power plant is estimated, which is in good agreement with that from CEMS observations of 0.17 ± 0.07 kg/s. This study has significantly contributed to the measurement of the mobile DOAS system on emission from air pollution sources, thus improving estimation accuracy.
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