Journals >Journal of Atmospheric and Environmental Optics
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2024
Volume: 19 Issue 3
10 Article(s)
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Progress of detection technology of nitrogen dioxide and organic nitrates
TONG Jinzhao, LIN Chuan, HU Renzhi, XIE Pinhua, WU Tao, WANG Jiawei, and CHEN Liang
Both nitrogen dioxide (NO2) and organic nitrates (ONs) are very important trace gases in the atmosphere. The concentration of NO2 is one of the most important indicators to assess the degree of air pollution. In addition, NO2 is the main source of tropospheric ozone and a significant precursor of photochemical smog andBoth nitrogen dioxide (NO2) and organic nitrates (ONs) are very important trace gases in the atmosphere. The concentration of NO2 is one of the most important indicators to assess the degree of air pollution. In addition, NO2 is the main source of tropospheric ozone and a significant precursor of photochemical smog and acid rain. Organic nitrates in the atmosphere are stable at low temperature and easy to decompose at high temperature, making them a potential source of NO2, and in other hand, they also have a certain impact on the global distribution of O3. Therefore, accurately obtaining the concentration of NO2 and ONs in the atmosphere is of great significance for studying atmospheric chemical processes. As early as the 1950s and 1960s, chemiluminescence and spectrophotometric techniques were used to measure NO2 in the ambient atmosphere. With the development of science and technology, differential optical absorption spectroscopy, laser induced fluorescence spectroscopy, tunable diode laser absorption spectroscopy, cavity attenuated phase shift spectroscopy, cavity ring down spectroscopy, and cavity enhanced absorption spectroscopy have been used to measure NO2 in various environments. Accurate measurement of ONs is of great importance in nitrogen cycle research. At present, the main measurement techniques of ONs include gas chromatography with electron capture detection and indirect measurements through pyrolysis conversion of ONs to NO2. The research status and development tendency of NO2 and ONs detection technologies in the environment both at home and abroad are reviewed, the principles, advantages and disadvantages of existing measurement methods are introduced and compared in detail, and the applications of various research methods in field observations are summarized..
Journal of Atmospheric and Environmental Optics
- Publication Date: May. 28, 2024
- Vol. 19, Issue 3, 265 (2024)
Solar spectral measurements at multipoint in Xizang
PU Dopwang, WANGMU Tsoja, GELSOR Norsang, WANG Qian, WANG Wenya, SHENG Min, WANG Mengmeng, and XU Gang
Strong solar irradiance in Tibetan Plateau provides heat source for the plateau's atmosphere, driving atmospheric circulation of East Asian and the "butterfly effect" of global climate change. Synchronous observation of the ground solar spectral characteristics in the region can provide effective field daStrong solar irradiance in Tibetan Plateau provides heat source for the plateau's atmosphere, driving atmospheric circulation of East Asian and the "butterfly effect" of global climate change. Synchronous observation of the ground solar spectral characteristics in the region can provide effective field data for studying the changes of the ground atmospheric environment, ecological environment and the utilization of solar energy resources. Using the international standard high-precision solar spectrometers RAMSES-ACC-VIS and SolarSIM-G, the solar spectra of Lhasa, Nyingchi, Nagchu, Shigatse and Mt. Everest in Xizang, China, were observed during 2020 to 2021. Synchronous observation of full band solar spectra (wavelength covering from 280 nm to 2500 nm) at high altitude in Xizang was conducted for the first time, the spatial distribution characteristics of solar spectral irradiance at multiple points in Xizang were studied, and the extinction factors such as absorption and scattering of solar spectrum at high altitude in Xizang were qualitatively analyzed. The results show that the annual average solar spectral irradiance in Shigatse and the Mt. Everest are the strongest, with the annual average spectral peak of more than 0.83 W/(m2·nm), the spectrum of Lhasa region is only inferior to that of Shigatse and Mt. Everest regions, with an average annual peak of about 0.73 W/(m2·nm), the annual average solar spectrum in Nagchu is lower than that in Lhasa, with a peak value of about 0.53 W/(m2·nm), and Nyingchi has the lowest solar spectrum. In terms of the spatial distribution characteristics of solar spectral irradiance, it is found that on the winter solstice, the spatial distribution of Xizang's spectral irradiance basically follows the zonal law, that is, the radiation intensity decreases with the increase of latitude, while on the summer solstice, the zonal regularity in Xizang is not so obvious due to rainy season weather..
Journal of Atmospheric and Environmental Optics
- Publication Date: May. 28, 2024
- Vol. 19, Issue 3, 292 (2024)
Influence of segmental fitting of aerosol spectrum on visibility calculation
ZHUANG Zibo, YANG Xiaoting, and TAI Hongda
Aiming at the problem that the deviation in the fitting of aerosol spectrum distribution function can seriously affect the calculation and prediction of visibility, a segmental fitting method combining Junge spectrum and Deirmendjian spectrum was proposed to improve the fitting accuracy of aerosol spectrum distributionAiming at the problem that the deviation in the fitting of aerosol spectrum distribution function can seriously affect the calculation and prediction of visibility, a segmental fitting method combining Junge spectrum and Deirmendjian spectrum was proposed to improve the fitting accuracy of aerosol spectrum distribution function, and its experimental verification was conducted in the atmospheric environment simulation chamber. Firstly, a multi-modal spectral distribution of aerosols is generated in the atmospheric simulation chamber, and a parametric model of aerosol spectral distribution is established. Then, the relative errors and correlation coefficients of the spectral functions fitted by the proposed method and the single spectral function method are compared and analyzed. Finally, the accuracy of the propsed method in calculating visibility is evaluated based on relative deviation and correlation. The results show that the average relative deviation between the visibility calculated using the proposed method and the observed value is 4.87%, with a correlation of R2 = 0.9847, which verifies that the fitting results have good accuracy, stability and consistency with the observed visibility, and can provide a support for improving the accuracy of visibility calculation and prediction..
Journal of Atmospheric and Environmental Optics
- Publication Date: May. 28, 2024
- Vol. 19, Issue 3, 301 (2024)
Highly sensitive and stable measurement of Cd in water based on electrodeposition enrichment-LIBS technology
SHU Yang, FANG Li, MA Mingjun, MENG Deshuo, and ZHAO Nanjing
Aiming at the highly sensitive and stable detection of trace amounts of Cd2+ in water, an experimental study based on Al sheet electrodeposition enrichment (ED) combined with laser-induced breakdown spectroscopy (LIBS) to detect Cd in water analysis method (ED-LIBS) is carried out. The effects of enrichment time, enricAiming at the highly sensitive and stable detection of trace amounts of Cd2+ in water, an experimental study based on Al sheet electrodeposition enrichment (ED) combined with laser-induced breakdown spectroscopy (LIBS) to detect Cd in water analysis method (ED-LIBS) is carried out. The effects of enrichment time, enrichment voltage, concentration of conductive solute KCl, and sandpaper polishing on the electrode surface, on Cd element enrichment are analyzed. The result shows that the enrichment stability of Cd element is improved after the Al flakes for electrical-deposition being polished by sandpaper. The optimized enrichment voltage, enrichment time and concentration of KCl are -2.4 V, 1200 s and 2 g/L, respectively. By using the proposed method, the detection limit and relative standard deviation of Cd element are 0.0021 mg/L and 3.30%, respectively, which meets the detection requirement of "Sanitary Standards for Drinking Water" and provides an optional method for the highly sensitive and stable analysis of trace Cd elements in water..
Journal of Atmospheric and Environmental Optics
- Publication Date: May. 28, 2024
- Vol. 19, Issue 3, 314 (2024)
Health and ecological risk assessment of heavy metals in atmospheric particulate matter in Nanjing
WU Lichun, LUO Xiaosan, CHENG Xiangyang, WANG Kun, and MIAO Mingrong
Heavy metals in atmospheric particulate matter not noly pollute the ecology but also affect human health. Therefore, their chemical form and bioavailability are of great significance for the evaluation of health and ecological risks. To compare and explore the bioavailability of fine particulate matter (PM2.5)and the eHeavy metals in atmospheric particulate matter not noly pollute the ecology but also affect human health. Therefore, their chemical form and bioavailability are of great significance for the evaluation of health and ecological risks. To compare and explore the bioavailability of fine particulate matter (PM2.5)and the ecological risk assessment of the total suspended particulates (TSP) in industrial areas and urban areas of Nanjing, China, PM2.5 and TSP samples were collected separetely from an industrial area and an urban area from 2016 to 2017, and elements such as Pb, Cd, Mn, Cu were analyzed in the samples. The results show that: (1) Cd in PM2.5 has high bioavailability and is a greater threat to human health, indicating that its emissions should be strictly controlled, (2) the average heavy metal pollution degree of TSP in the industrial area is higher than that in the urban area, with Cd and Pb elements at an extremely strong ecological hazard level..
Journal of Atmospheric and Environmental Optics
- Publication Date: May. 28, 2024
- Vol. 19, Issue 3, 322 (2024)
Influence of vehicle restriction on air quality in Xi'an and its model analysis
HU Tian, LOU Chunhui, and WU Yarui
In recent years, air pollution has become one of the important factors limiting the improvement of urban living environment quality in Xi'an City, China. The local government has taken a series of measures to control air pollution, among which the motor vehicle restriction policy is most favored due to its strong fIn recent years, air pollution has become one of the important factors limiting the improvement of urban living environment quality in Xi'an City, China. The local government has taken a series of measures to control air pollution, among which the motor vehicle restriction policy is most favored due to its strong feasibility, less public investment and simple operation. Based on the analysis of the trend of air quality changes in Xi'an from 2016 to 2020, R language is used to establish a generalized additive model for the relationship between relevant influencing factors (motor vehicle restriction policy, average wind speed, relative humidity and average temperature) and air quality, and then fitting analysis and correlation test are carried out. The results show that there is a significant correlation between vehicle restriction policy and air quality improvement in Xi'an City..
Journal of Atmospheric and Environmental Optics
- Publication Date: May. 28, 2024
- Vol. 19, Issue 3, 333 (2024)
Analysis of a synergistic pollution process of PM2.5 and ozone in Beijing-Tianjin-Hebei Region
FANG Wensheng, CAO Nianwen, and SHI Xinchi
A synergistic pollution process of PM2.5 and ozone (O3) occurred in Beijing-Tianjin-Hebei Region, China, from April 16 to 22, 2018. In order to gain a deeper understanding of the occurrence and the causes of the synergetic pollution, multi-source data were used to comprehensively analyze the meteorological elements, grA synergistic pollution process of PM2.5 and ozone (O3) occurred in Beijing-Tianjin-Hebei Region, China, from April 16 to 22, 2018. In order to gain a deeper understanding of the occurrence and the causes of the synergetic pollution, multi-source data were used to comprehensively analyze the meteorological elements, ground conditions and vertical characteristics of this synergistic process, and according to the hourly mass concentration changes of the two pollutants, the pollution process was divided into three processes: growth, high level, and decline. The results show that: (1) There is a good corresponding relationship between the air temperature, air pressure, relative humidity and pollutant mass concentration change during the pollution process, the wind speed changes significantly during the conversion of different processes, and O3 pollution occurs most at 16:00 every day. (2) When the Mongolian low pressure is near the Beijing-Tianjin-Hebei Region and the Beijing-Tianjin-Hebei Region is on the periphery of the high pressure, pollutants are easy to accumulate and transmit in the static weather. After the transit of the cold front, the mass concentration of pollutants drops rapidly, and the air quality is higher under the control of northeast high pressure. (3) The vertical distribution of aerosols in the early morning of April 19 mainly included mixed and sand dust aerosols, with pollutants mainly coming from the south and southwest of Beijing-Tianjin-Hebei Region, while at noon of April 19, the vertical distribution of aerosols mainly included mixed type, pollution type and sand dust type aerosols, with pollutants mainly coming from the north of Beijing-Tianjin-Hebei Region. High altitude transmission is easy to bring sand dust aerosols, and when the ground pollution is serious, the surface air mass transmission is mainly external horizontal transmission. (4) The hourly average mass concentration of PM2.5 is extremely significantly positively correlated with air temperature, significantly positively correlated with relative humidity, while extremely significantly negatively correlated with air pressure and wind speed. The hourly average mass concentration of ozone shows an extremely significant positive correlation with air temperature and wind speed, and an extremely significant negative correlation with air pressure and relative humidity. There is a significant positive correlation between PM2.5 and O3, and the high hourly mass mass concentrations of the two pollutants mostly occur in the southeast to southwest wind range with the wind directions from 135° to 225°..
Journal of Atmospheric and Environmental Optics
- Publication Date: May. 28, 2024
- Vol. 19, Issue 3, 342 (2024)
Personal exposure levels of air pollutants in two commuting modes in Urumqi City
ZHUANG Dan, CHEN Xuegang, and DONG Yu
In July 2022, mobile monitoring was conducted on the personal exposure concentration of PM2.5, O3 and NO2 air pollutants under two commuting modes of bus and walking in Urumqi, and the saptiotemporal changes and influencing factors of individual exposure concentration of pollutants under the two commuting modes were anIn July 2022, mobile monitoring was conducted on the personal exposure concentration of PM2.5, O3 and NO2 air pollutants under two commuting modes of bus and walking in Urumqi, and the saptiotemporal changes and influencing factors of individual exposure concentration of pollutants under the two commuting modes were analyzed. The results show that: (1) In terms of temporal distribution, individual exposure concentration of PM2.5 decreases in the sequence of morning peak, off-peak, evening peak under bus mode; both individual exposure concentrations of O3 and NO2 show off-peak > evening peak > morning peak for both bus and walking modes. In morning peak, PM2.5 exposure concentration under bus mode is higher than that under walking mode, while the exposure concentrations of O3 and NO2 under walking mode are higher than those of under bus mode. In evening peak, the exposure concentrations of O3 and NO2 under walking mode are higher than those of under bus mode. In off-peak, the exposure concentration of NO2 under bus mode is higher that of under walking mode, walking O3 > bus. In terms of daily variation, the exposure concentrations of PM2.5 under bus mode is higher than that of under walk mode, while the exposure concentrations of O3 and NO2 under walk mode are higher than those of under bus model. And all the exposure concentrations of PM2.5, O3 in weekdays are higher than those in weekends for both bus and walking modes. (2) Spatially, PM2.5 concentration under foot mode is higher than that of under bus mode, while O3 and NO2 are opposite. In addition, the personal exposure concentration of pollutants in Liyushan South Road is relatively higher than that of in other road sections. Especially, the personal exposure concentration of pollutants is lower at the crossroads while comparatively higher before and after traffic lights. (3) There is a significantly positive correlation between the PM2.5 and O3 exposure concentrations and the background values for both bus and walking modes. Temperature is significantly correlated with the concentrations of PM2.5, O3, NO2 produced both in commuting modes of bus and walking. Humidity is significantly related to NO2 produced in commuting mode of buses and PM2.5, O3 and NO2 produced in commuting mode of walking. The wind speed is also significantly correlated to PM2.5, O3 and NO2 produced in commuting mode of walking, while there is a significant correlation between wind direction and PM2.5, O3, NO2 produced in commuting mode of bus and PM2.5 and O3 produced in walking mode. Finally, based on the research results in this work, , some suggestions are put forward on the residents' travel mode in order to reduce the harmful degree of air pollutant exposure to human body..
Journal of Atmospheric and Environmental Optics
- Publication Date: May. 28, 2024
- Vol. 19, Issue 3, 357 (2024)
Screening method of sea surface signals based on CALIOP dual-wavelength data
LUO Dunyi, WU Dong, and HE Yan
Based on the sea surface backscattering model, a space-borne lidar data screening method using CALIOP dual-wavelength sea surface signal for data quality control is proposed. The global sea surface wind speed is retrieved from CALIOP's Version 4.1.0 level 1 data from January to September 2018. In order to improve dBased on the sea surface backscattering model, a space-borne lidar data screening method using CALIOP dual-wavelength sea surface signal for data quality control is proposed. The global sea surface wind speed is retrieved from CALIOP's Version 4.1.0 level 1 data from January to September 2018. In order to improve data availability, under the condition of detecting sea surface wind speed in cloudless sea area, the cloud-penetrating CALIOP data were added, and then wind speed inversion was carried out after atmospheric correction and dual-wavelength signal quality control. At last, quasi-synchronous AMSR-2 wind speed data were used as reference values for verification. The two empirical relationships of Cox-Munk model and Hu model were used to invert wind speed respectively. For the data from January to March, the standard deviations of the former model are 1.14, 1.18 and 1.16m /s, respectively, with correlation coefficients of 0.90, 0.91 and 0.91, while the standard deviations of the latter are 1.17, 1.19 and 1.17m /s, respectively, with correlation coefficients of 0.91, 0.91 and 0.91. In addition, compared with the inversion study in cloudless sea, the available data amount using the proposed method increases by about 45.5%. The results show that the method proposed can not only ensure the accuracy of inversion but also effectively improve the utilization rate of data, which can provide more data sources for the study of sea surface wind field..
Journal of Atmospheric and Environmental Optics
- Publication Date: May. 28, 2024
- Vol. 19, Issue 3, 371 (2024)
Lightweight underwater image enhancement network based on cross-scale deep distillation feature perception
WU Xiaohua, LI Zenglu, XU Zhanghua, and ZHOU Jingchun
Underwater image enhancement technology has the potential to improve the quality and visibility of underwater images, which has important application value in enriching digital media resources, underwater exploration, underwater communication, and other fields. In recent years, deep learning methods have achieved remarUnderwater image enhancement technology has the potential to improve the quality and visibility of underwater images, which has important application value in enriching digital media resources, underwater exploration, underwater communication, and other fields. In recent years, deep learning methods have achieved remarkable results in underwater image enhancement. However, the existing methods suffer from high computational complexity, which limits their application in scenarios with limited computational resources. To address this problem, a lightweight underwater image enhancement method is proposed. The method is based on cross-scale depth distillation feature perception and adopts a U-shaped network structure, which can significantly reduce the model parameter size while ensuring the extraction of nonlinear abstract layers. The experimental results show that the proposed method has achieved competitive results in both visual effects and objective evaluation metrics..
Journal of Atmospheric and Environmental Optics
- Publication Date: May. 28, 2024
- Vol. 19, Issue 3, 381 (2024)
