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Atmospheric aerosols play a crucial role in climate change, especially in the Himalayas and Tibetan Plateau. Here, we present the seasonal and diurnal characteristics of aerosol vertical profiles measured using a Mie lidar, along with surface black carbon (BC) measurements, at Mt. Qomolangma (QOMS), in the central Himalayas, in 2018–2019. Lidar-retrieved profiles of aerosols showed a distinct seasonal pattern of aerosol loading (aerosol extinction coefficient, AEC), with a maximum in the pre-monsoon (19.8 ± 22.7 Mm−1 of AEC) and minimum in the summer monsoon (7.0 ± 11.2 Mm−1 of AEC) seasons. The diurnal variation characteristics of AEC and BC were quite different in the non-monsoon seasons with enriched aerosols being maintained from 00:00 to 10:00 in the pre-monsoon season. The major aerosol types at QOMS were identified as background, pollution, and dust aerosols, especially during the pre-monsoon season. The occurrence of pollution events influenced the vertical distribution, seasonal/diurnal patterns, and types of aerosols. Source contribution of BC based on the weather research and forecasting chemical model showed that approximately 64.2% ± 17.0% of BC at the QOMS originated from India and Nepal in South Asia during the non-monsoon seasons, whereas approximately 47.7% was from local emission sources. In particular, the high abundance of BC at the QOMS in the pre-monsoon season was attributed to biomass burning, whereas anthropogenic emissions were the likely sources during the other seasons. The maximum aerosol concentration appeared in the near-surface layer (approximately 4.3 km ASL), and high concentrations of transported aerosols were mainly found at 4.98, 4.58, 4.74, and 4.88 km ASL in the pre-monsoon, monsoon, post-monsoon, and winter seasons, respectively. The investigation of the vertical profiles of aerosols at the QOMS can help verify the representation of aerosols in the air quality model and satellite products and regulate the anthropogenic disturbance over the Tibetan Plateau.
Yan Xiang; Tianshu Zhang; Jianguo Liu; Xin Wan; Mark Loewen; Xintong Chen; Shichang Kang; Yibin Fu; Lihui Lv; Wenqing Liu; Zhiyuan Cong. Vertical profile of aerosols in the Himalayas revealed by lidar: New insights into their seasonal/diurnal patterns, sources, and transport. Environmental Pollution 2021, 285, 117686 .
AMA StyleYan Xiang, Tianshu Zhang, Jianguo Liu, Xin Wan, Mark Loewen, Xintong Chen, Shichang Kang, Yibin Fu, Lihui Lv, Wenqing Liu, Zhiyuan Cong. Vertical profile of aerosols in the Himalayas revealed by lidar: New insights into their seasonal/diurnal patterns, sources, and transport. Environmental Pollution. 2021; 285 ():117686.
Chicago/Turabian StyleYan Xiang; Tianshu Zhang; Jianguo Liu; Xin Wan; Mark Loewen; Xintong Chen; Shichang Kang; Yibin Fu; Lihui Lv; Wenqing Liu; Zhiyuan Cong. 2021. "Vertical profile of aerosols in the Himalayas revealed by lidar: New insights into their seasonal/diurnal patterns, sources, and transport." Environmental Pollution 285, no. : 117686.
A dry-ambient aerosol size spectrometer (DAASS) was previously developed to conduct measurements of aerosol water content at ambient relative humidity (RH) conditions. However, the RH difference of ambient RH and DAASS conditioning humidity (i.e., 10–20%, particularly when the DAASS operated at a high ambient RH) may introduce uncertainties in estimation of aerosol water content. In this study, we present a prototype of an RH-controlled DAASS. By employing an active RH controlling method, we resolve the discrepancy between the ambient RH and the DAASS conditioning RH, therefore extending the accurate measurement of aerosol water content to a wide RH range. The performance of this RH-controlled DAASS was characterized by both the laboratory evaluation and a 10-day field deployment. Results showed that the DAASS conditioning RH agreed well with the ambient RH (R2 of 0.993 when ambient RH up to 90%), with an average RH offset of less than 1.5%. The fraction of aerosol-bound water in the total ambient aerosol volume was ~10% under RHs below 50% and increased to ~50% when the ambient RH reached above 85%.
HaoSheng Dai; Huaqiao Gui; Jiaoshi Zhang; Xiuli Wei; Zhibo Xie; Jiejie Bian; Da-Ren Chen; Jianguo Liu. An active RH-controlled dry-ambient aerosol size spectrometer (DAASS) for the accurate measurement of ambient aerosol water content. Journal of Aerosol Science 2021, 158, 105831 .
AMA StyleHaoSheng Dai, Huaqiao Gui, Jiaoshi Zhang, Xiuli Wei, Zhibo Xie, Jiejie Bian, Da-Ren Chen, Jianguo Liu. An active RH-controlled dry-ambient aerosol size spectrometer (DAASS) for the accurate measurement of ambient aerosol water content. Journal of Aerosol Science. 2021; 158 ():105831.
Chicago/Turabian StyleHaoSheng Dai; Huaqiao Gui; Jiaoshi Zhang; Xiuli Wei; Zhibo Xie; Jiejie Bian; Da-Ren Chen; Jianguo Liu. 2021. "An active RH-controlled dry-ambient aerosol size spectrometer (DAASS) for the accurate measurement of ambient aerosol water content." Journal of Aerosol Science 158, no. : 105831.
Atmospheric pollutants over the Himalayas and Tibetan Plateau (HTP) have potential implications for accelerating the melting of glaciers, damaging air quality, water sources and grasslands, and threatening climate on regional and global scales. Improved knowledge of the variabilities, sources, drivers and transport pathways of atmospheric pollutants over the HTP is significant for regulatory and control purposes. In this study, we quantify the variability, source, and transport of CO in the urban areas over the HTP by using in situ measurement, GEOS-Chem model tagged CO simulation, and the analysis of meteorological fields. Diurnal, seasonal, and interannual variabilities of CO over the HTP are investigated with ∼ 6 years (January 2015 to July 2020) of surface CO measurements in eight cities over the HTP. Annual mean of surface CO volume mixing ratio (VMR) over the HTP varied over 318.3 ± 71.6 to 901.6 ± 472.2 ppbv, and a large seasonal cycle was observed with high levels of CO in the late autumn to spring and low levels of CO in summer to early autumn. The diurnal cycle is characterized by a bimodal pattern with two maximums in later morning and midnight, respectively. Surface CO VMR from 2015 to 2020 in most cities over the HTP showed negative trends. The IASI satellite observations are for the first time used to assess the performance of the GEOS-Chem model for the specifics of the HTP. The GEOS-Chem simulations tend to underestimate the IASI observations but can capture the measured seasonal cycle of CO total column over the HTP. Distinct dependencies of CO on a short lifetime species of NO2 in almost all cities over the HTP were observed, implying local emissions to be predominant. By turning off the emission inventories within the HTP in GEOS-Chem tagged CO simulation, the relative contribution of long-range transport was evaluated. The results showed that transport ratios of primary anthropogenic source, primary biomass burning (BB) source, and secondary oxidation source to the surface CO VMR over the HTP varied over 35 % to 61 %, 5 % to 21 %, and 30 % to 56 %, respectively. The anthropogenic contribution is dominated by the South Asia and East Asia (SEAS) region throughout the year (58 % to 91 %). The BB contribution is dominated by the SEAS region in spring (25 % to 80 %) and the Africa (AF) region in July–February (30 %–70 %). This study concluded that the main source of CO in urban areas over the HTP is due to local and SEAS anthropogenic and BB emissions and oxidation sources, which differ from the black carbon that is mainly attributed to the BB source from South-East Asia. The decreasing trends in surface CO VMR since 2015 in most cities over the HTP are attributed to the reduction in local and transported CO emissions in recent years.
Youwen Sun; Hao Yin; Yuan Cheng; Qianggong Zhang; Bo Zheng; Justus Notholt; Xiao Lu; Cheng Liu; Yuan Tian; Jianguo Liu. Quantifying variability, source, and transport of CO in the urban areas over the Himalayas and Tibetan Plateau. Atmospheric Chemistry and Physics 2021, 21, 9201 -9222.
AMA StyleYouwen Sun, Hao Yin, Yuan Cheng, Qianggong Zhang, Bo Zheng, Justus Notholt, Xiao Lu, Cheng Liu, Yuan Tian, Jianguo Liu. Quantifying variability, source, and transport of CO in the urban areas over the Himalayas and Tibetan Plateau. Atmospheric Chemistry and Physics. 2021; 21 (11):9201-9222.
Chicago/Turabian StyleYouwen Sun; Hao Yin; Yuan Cheng; Qianggong Zhang; Bo Zheng; Justus Notholt; Xiao Lu; Cheng Liu; Yuan Tian; Jianguo Liu. 2021. "Quantifying variability, source, and transport of CO in the urban areas over the Himalayas and Tibetan Plateau." Atmospheric Chemistry and Physics 21, no. 11: 9201-9222.
We report the development of a laser gas analyzer that measures gas concentrations at a data rate of 100 Hz. This fast data rate helps eddy covariance calculations for gas fluxes in turbulent high wind speed environments. The laser gas analyzer is based on derivative laser absorption spectroscopy and set for measurements of water vapor (H2O, at wavelength ~1392 nm) and carbon dioxide (CO2, at ~2004 nm). This instrument, in combination with an ultrasonic anemometer, has been tested experimentally in both marine and terrestrial environments. First, we compared the accuracy of results between the laser gas analyzer and a high-quality commercial instrument with a max data rate of 20 Hz. We then analyzed and compared the correlation of H2O flux results at data rates of 100 Hz and 20 Hz in both high and low wind speeds to verify the contribution of high frequency components. The measurement results show that the contribution of 100 Hz data rate to flux calculations is about 11% compared to that measured with 20 Hz data rate, in an environment with wind speed of ~10 m/s. Therefore, it shows that the laser gas analyzer with high detection frequency is more suitable for measurements in high wind speed environments.
Mingxing Li; Ruifeng Kan; Yabai He; Jianguo Liu; Zhenyu Xu; Bing Chen; Lu Yao; Jun Ruan; Huihui Xia; Hao Deng; Xueli Fan; Bangyi Tao; Xueling Cheng. Development of a Laser Gas Analyzer for Fast CO2 and H2O Flux Measurements Utilizing Derivative Absorption Spectroscopy at a 100 Hz Data Rate. Sensors 2021, 21, 3392 .
AMA StyleMingxing Li, Ruifeng Kan, Yabai He, Jianguo Liu, Zhenyu Xu, Bing Chen, Lu Yao, Jun Ruan, Huihui Xia, Hao Deng, Xueli Fan, Bangyi Tao, Xueling Cheng. Development of a Laser Gas Analyzer for Fast CO2 and H2O Flux Measurements Utilizing Derivative Absorption Spectroscopy at a 100 Hz Data Rate. Sensors. 2021; 21 (10):3392.
Chicago/Turabian StyleMingxing Li; Ruifeng Kan; Yabai He; Jianguo Liu; Zhenyu Xu; Bing Chen; Lu Yao; Jun Ruan; Huihui Xia; Hao Deng; Xueli Fan; Bangyi Tao; Xueling Cheng. 2021. "Development of a Laser Gas Analyzer for Fast CO2 and H2O Flux Measurements Utilizing Derivative Absorption Spectroscopy at a 100 Hz Data Rate." Sensors 21, no. 10: 3392.
China has made great efforts to monitor and control air pollution in the past decade. Comprehensive characterization and understanding of pollutants in three-dimensions are, however, still lacking. Here, we used data from an observation network consisting of 13 aerosol lidars and more than 1000 ground observation stations combined with a data assimilation technique to conduct a comprehensive analysis of extreme heavy aerosol pollution (HAP) over the North China Plain (NCP) from November–December 2017. During the studied period, the maximum hourly mass concentration of surface PM2.5 reached ∼390 µg m−3. After assimilation, the correlation between model results and the independent observation sub-dataset was ∼50 % higher than that without the assimilation, and the root mean square error was reduced by ∼40 %. From pollution development to dissipation, we divided the HAP in the NCP (especially in Beijing) into four phases: an early phase (EP), a transport phase (TP), an accumulation phase (AP), and a removal phase (RP). We then analyzed the evolutionary characteristics of PM2.5 concentration during different phases on the surface and in 3-D space. We found that the particles were mainly transported from south to north at a height of 1–2 km (during EP and RP) and near the surface (during TP and AP). The amounts of PM2.5 advected into Beijing with the maximum transport flux intensity (TFI) were through the pathways in the relative order of the southwest > southeast > east pathways. The dissipation of PM2.5 in the RP stage (with negative TFI) was mainly from north to south with an average transport height of ∼1 km above the surface. Our results quantified the multi-dimensional distribution and evolution of PM2.5 concentration over the NCP, which may help policymakers develop efficient air pollution control strategies.
Yan Xiang; Tianshu Zhang; Chaoqun Ma; Lihui Lv; Jianguo Liu; Wenqing Liu; Yafang Cheng. Lidar vertical observation network and data assimilation reveal key processes driving the 3-D dynamic evolution of PM2.5 concentrations over the North China Plain. Atmospheric Chemistry and Physics 2021, 21, 7023 -7037.
AMA StyleYan Xiang, Tianshu Zhang, Chaoqun Ma, Lihui Lv, Jianguo Liu, Wenqing Liu, Yafang Cheng. Lidar vertical observation network and data assimilation reveal key processes driving the 3-D dynamic evolution of PM2.5 concentrations over the North China Plain. Atmospheric Chemistry and Physics. 2021; 21 (9):7023-7037.
Chicago/Turabian StyleYan Xiang; Tianshu Zhang; Chaoqun Ma; Lihui Lv; Jianguo Liu; Wenqing Liu; Yafang Cheng. 2021. "Lidar vertical observation network and data assimilation reveal key processes driving the 3-D dynamic evolution of PM2.5 concentrations over the North China Plain." Atmospheric Chemistry and Physics 21, no. 9: 7023-7037.
The major air pollutant emissions have decreased, and the overall air quality has substantially improved across China in recent years as a consequence of active clean air policies for mitigating severe air pollution problems. As key precursors of formaldehyde (HCHO) and ozone (O3), the volatile organic compounds (VOCs) in China are still increasing due to the lack of mitigation measures for VOCs. In this study, we investigated the drivers of HCHO variability from 2015 to 2019 over Hefei, eastern China, by using ground-based high-resolution Fourier transform infrared (FTIR) spectroscopy and GEOS-Chem model simulation. Seasonal and interannual variabilities of HCHO over Hefei were analyzed and hydroxyl (OH) radical production rates from HCHO photolysis were evaluated. The relative contributions of emitted and photochemical sources to the observed HCHO were analyzed by using ground-level carbon monoxide (CO) and Ox (O3 + nitrogen oxide (NO2)) as tracers for emitted and photochemical HCHO, respectively. Contributions of emission sources from various categories and geographical regions to the observed HCHO summertime enhancements were determined by using a series of GEOS-Chem sensitivity simulations. The column-averaged dry air mole fractions of HCHO (XHCHO) reached a maximum monthly mean value of 1.1 ± 0.27 ppbv in July and a minimum monthly mean value of 0.4 ± 0.11 ppbv in January. The XHCHO time series from 2015 to 2019 over Hefei showed a positive change rate of 2.38 ± 0.71 % per year. The photochemical HCHO is the dominant source of atmospheric HCHO over Hefei for most of the year (68.1 %). In the studied years, the HCHO photolysis was an important source of OH radicals over Hefei during all sunlight hours of both summer and winter days. The oxidations of both methane (CH4) and nonmethane VOCs (NMVOCs) dominate the HCHO production over Hefei and constitute the main driver of its summertime enhancements. The NMVOC-related HCHO summertime enhancements were dominated by the emissions within eastern China. The observed increasing change rate of HCHO from 2015 to 2019 over Hefei was attributed to the increase in photochemical HCHO resulting from increasing change rates of both CH4 and NMVOC oxidations, which overwhelmed the decrease in emitted HCHO. This study provides a valuable evaluation of recent VOC emissions and regional photochemical capacity in China. In addition, understanding the sources of HCHO is a necessary step for tackling air pollution in eastern China and mitigating the emissions of pollutants.
Youwen Sun; Hao Yin; Cheng Liu; Lin Zhang; Yuan Cheng; Mathias Palm; Justus Notholt; Xiao Lu; Corinne Vigouroux; Bo Zheng; Wei Wang; Nicholas Jones; Changong Shan; Min Qin; Yuan Tian; Qihou Hu; Fanhao Meng; Jianguo Liu. Mapping the drivers of formaldehyde (HCHO) variability from 2015 to 2019 over eastern China: insights from Fourier transform infrared observation and GEOS-Chem model simulation. Atmospheric Chemistry and Physics 2021, 21, 6365 -6387.
AMA StyleYouwen Sun, Hao Yin, Cheng Liu, Lin Zhang, Yuan Cheng, Mathias Palm, Justus Notholt, Xiao Lu, Corinne Vigouroux, Bo Zheng, Wei Wang, Nicholas Jones, Changong Shan, Min Qin, Yuan Tian, Qihou Hu, Fanhao Meng, Jianguo Liu. Mapping the drivers of formaldehyde (HCHO) variability from 2015 to 2019 over eastern China: insights from Fourier transform infrared observation and GEOS-Chem model simulation. Atmospheric Chemistry and Physics. 2021; 21 (8):6365-6387.
Chicago/Turabian StyleYouwen Sun; Hao Yin; Cheng Liu; Lin Zhang; Yuan Cheng; Mathias Palm; Justus Notholt; Xiao Lu; Corinne Vigouroux; Bo Zheng; Wei Wang; Nicholas Jones; Changong Shan; Min Qin; Yuan Tian; Qihou Hu; Fanhao Meng; Jianguo Liu. 2021. "Mapping the drivers of formaldehyde (HCHO) variability from 2015 to 2019 over eastern China: insights from Fourier transform infrared observation and GEOS-Chem model simulation." Atmospheric Chemistry and Physics 21, no. 8: 6365-6387.
The supersaturated condensation of atmospheric aerosol is important in the study of mechanisms of cloud condensation and even heavy air pollution. The existing technology cannot realize accurate dynamic control of wide range supersaturation, so it is difficult to study condensation growth characteristics of nanoparticles through different levels of supersaturation. Here, a supersaturated condensation growth measurement system with three-stage microscope pipes was developed. The resolution of supersaturated condensation system is 0.14, within the range of 0.92 to 2.33 after calibration. Stabilization time is only about 80 s for saturation range 0.92–1.01, which helps to control saturation rapidly, and the control deviation of saturation is no more than 0.06. Measurement of different supersaturated condensation growth control conditions showed that, the particle size increased significantly compared with hygroscopic growth at high humidity. For single-component particles, the increase in size increased to a similar size at the same saturation, with a difference within 7.4%. The increase in size for ammonium sulfate (AS) increased by 13.4–30.2% relative to that of glucose. For the mixed-component, the increase in size decreased about 15.9–25.0% with the increase of the glucose. Because the glucose coating on the surface of AS have hindered particle growth. This also shows that atmospheric ultrafine particles, especially inorganic salt particles, will rapidly grow into larger particles under supersaturated conditions such as increased environmental humidity, thus having some impact on environmental pollution and climate change.
Jiejie Bian; Huaqiao Gui; Xiuli Wei; Tongzhu Yu; Zhibo Xie; Jie Wang; Jianguo Liu. Development and Application of a Wide Dynamic Range and High Resolution Atmospheric Aerosol Water-Based Supersaturation Condensation Growth Measurement System. Atmosphere 2021, 12, 558 .
AMA StyleJiejie Bian, Huaqiao Gui, Xiuli Wei, Tongzhu Yu, Zhibo Xie, Jie Wang, Jianguo Liu. Development and Application of a Wide Dynamic Range and High Resolution Atmospheric Aerosol Water-Based Supersaturation Condensation Growth Measurement System. Atmosphere. 2021; 12 (5):558.
Chicago/Turabian StyleJiejie Bian; Huaqiao Gui; Xiuli Wei; Tongzhu Yu; Zhibo Xie; Jie Wang; Jianguo Liu. 2021. "Development and Application of a Wide Dynamic Range and High Resolution Atmospheric Aerosol Water-Based Supersaturation Condensation Growth Measurement System." Atmosphere 12, no. 5: 558.
We have developed a portable near-infrared laser heterodyne radiometer (LHR) for quasi-simultaneous measurements of atmospheric carbon dioxide (CO2), methane (CH4), water vapor (H2O) and oxygen (O2) column absorption by using three distributed-feedback diode lasers as the local oscillators of the heterodyne detection. The developed system shows good performance in terms of its high spectral resolution of 0.066 cm−1 and a low solar power detection noise which was about 2 times the theoretical quantum limit. Its measurement precision of the column-averaged mole fraction for CO2 and CH4 is within 1.1%, based on the standard deviation from the mean value of the retrieved results for a clean sky. The column abundance information of the O2 is used to correct for the variations and uncertainties of atmosphere pressure, the solar altitude angle, and the prior profiles of pressure and temperature. Comparison measurements of daily column-averaged atmospheric mole fractions of CO2, CH4 and H2O, between our developed LHR and a greenhouse gas observing satellite, show a good agreement, which proves the reliability of our developed system.
Hao Deng; Chenguang Yang; Zhenyu Xu; Mingxing Li; An Huang; Lu Yao; Mai Hu; Bing Chen; Yabai He; Ruifeng Kan; Jianguo Liu. Development of a laser heterodyne spectroradiometer for high-resolution measurements of CO2, CH4, H2O and O2 in the atmospheric column. Optics Express 2021, 29, 2003 -2013.
AMA StyleHao Deng, Chenguang Yang, Zhenyu Xu, Mingxing Li, An Huang, Lu Yao, Mai Hu, Bing Chen, Yabai He, Ruifeng Kan, Jianguo Liu. Development of a laser heterodyne spectroradiometer for high-resolution measurements of CO2, CH4, H2O and O2 in the atmospheric column. Optics Express. 2021; 29 (2):2003-2013.
Chicago/Turabian StyleHao Deng; Chenguang Yang; Zhenyu Xu; Mingxing Li; An Huang; Lu Yao; Mai Hu; Bing Chen; Yabai He; Ruifeng Kan; Jianguo Liu. 2021. "Development of a laser heterodyne spectroradiometer for high-resolution measurements of CO2, CH4, H2O and O2 in the atmospheric column." Optics Express 29, no. 2: 2003-2013.
Yan Xiang; Tianshu Zhang; Chaoqun Ma; Lihui Lv; Jianguo Liu; Wenqing Liu; Yafang Cheng. Supplementary material to "Lidar vertical observation network and data assimilation reveal key processes driving the 3-D dynamic evolution of PM2.5 concentrations over the North China Plain". 2021, 1 .
AMA StyleYan Xiang, Tianshu Zhang, Chaoqun Ma, Lihui Lv, Jianguo Liu, Wenqing Liu, Yafang Cheng. Supplementary material to "Lidar vertical observation network and data assimilation reveal key processes driving the 3-D dynamic evolution of PM2.5 concentrations over the North China Plain". . 2021; ():1.
Chicago/Turabian StyleYan Xiang; Tianshu Zhang; Chaoqun Ma; Lihui Lv; Jianguo Liu; Wenqing Liu; Yafang Cheng. 2021. "Supplementary material to "Lidar vertical observation network and data assimilation reveal key processes driving the 3-D dynamic evolution of PM2.5 concentrations over the North China Plain"." , no. : 1.
China has made great efforts to monitor and control air pollution in the past decade. Comprehensive characterization and understanding of pollutants in three-dimension (3-D) are, however, still lacking. Here, we used data from an observation network consisting of 13 aerosol lidars and more than 1000 ground observation stations, combined with a data assimilation technique, to conduct a comprehensive analysis of an extreme heavy aerosol pollution (HAP) over the North China Plain (NCP) from November–December 2017. During the studied period, the maximum hourly mass concentration of surface PM2.5 reached ~390 μg m−3. After assimilation, the correlation between model results and the independent observation sub-dataset was ~50 % higher than the that without the assimilation, and the root mean square error was reduced by ~40 %. From pollution development to dissipation, we divided the HAP in the NCP (especially in Beijing) into four phases – an early phase (EP), a transport phase (TP), an accumulation phase (AP), and a removal phase (RP). We then analyzed the evolutionary characteristics of PM2.5 concentration during different phases on the surface and in 3-D space. We found that the particles were mainly transported from south to north at a height of 1–2 km (during EP and RP) and near the surface (during TP and AP). The amounts of PM2.5 advected into Beijing with the maximum transport flux intensity (TFI) were through the pathways in the relative order of the southwest > southeast > east pathways. The dissipation of PM2.5 in the RP stage (with negative TFI) was mainly from north to south, with an average transport height of ~1 km above the surface. Our results quantified the multi-dimensional distribution and evolution of PM2.5 concentration over the NCP, which may help policymakers develop efficient air pollution control strategies.
Yan Xiang; Tianshu Zhang; Chaoqun Ma; Lihui Lv; Jianguo Liu; Wenqing Liu; Yafang Cheng. Lidar vertical observation network and data assimilation reveal key processes driving the 3-D dynamic evolution of PM2.5 concentrations over the North China Plain. 2021, 2021, 1 -23.
AMA StyleYan Xiang, Tianshu Zhang, Chaoqun Ma, Lihui Lv, Jianguo Liu, Wenqing Liu, Yafang Cheng. Lidar vertical observation network and data assimilation reveal key processes driving the 3-D dynamic evolution of PM2.5 concentrations over the North China Plain. . 2021; 2021 ():1-23.
Chicago/Turabian StyleYan Xiang; Tianshu Zhang; Chaoqun Ma; Lihui Lv; Jianguo Liu; Wenqing Liu; Yafang Cheng. 2021. "Lidar vertical observation network and data assimilation reveal key processes driving the 3-D dynamic evolution of PM2.5 concentrations over the North China Plain." 2021, no. : 1-23.
An attempt has been made in correspondence to explain the consequences of chemical pollution after the explosion of ammonium nitrate (AN) in Beirut (capital of Lebanon). The effects of chemicals in the air, soil, and water have been discussed. In addition, the study emphasizes on the research to restore the environment and enhanced safety measurements.
Sajid Ur Rehman; Rida Ahmed; Kun Ma; Shuai Xu; Muhammad Adnan Aslam; Hong Bi; Jianguo Liu; Junfeng Wang. Ammonium nitrate is a risk for environment: A case study of Beirut (Lebanon) chemical explosion and the effects on environment. Ecotoxicology and Environmental Safety 2021, 210, 111834 .
AMA StyleSajid Ur Rehman, Rida Ahmed, Kun Ma, Shuai Xu, Muhammad Adnan Aslam, Hong Bi, Jianguo Liu, Junfeng Wang. Ammonium nitrate is a risk for environment: A case study of Beirut (Lebanon) chemical explosion and the effects on environment. Ecotoxicology and Environmental Safety. 2021; 210 ():111834.
Chicago/Turabian StyleSajid Ur Rehman; Rida Ahmed; Kun Ma; Shuai Xu; Muhammad Adnan Aslam; Hong Bi; Jianguo Liu; Junfeng Wang. 2021. "Ammonium nitrate is a risk for environment: A case study of Beirut (Lebanon) chemical explosion and the effects on environment." Ecotoxicology and Environmental Safety 210, no. : 111834.
Significant contribution of ultrafine particles in the atmosphere to the cloud condensation nuclei and precipitation has been evidenced. The correlation between the condensation growth and chemical composition of particles is essential in the atmospheric studies. To reduce the lower detection limit of ATOFMS (currently at 200 nm), a water-based particle size amplifier, consisted of a tubing inner-lined with an expanded polytetrafluoroethylene layer and temperature-controlled in three sections, was designed, and its amplification performance was evaluated. With the use of the particle size amplifier, the peaks of Na and Cl in the mass spectra of 50 nm NaCl particles were obviously observed. Further, 50 nm NaCl/Dicarboxylic Acid (DA) particles were generated and characterized by ATOFMS with the amplifier and the sizes of ultrafine particles after the amplifier was measured by an Aerodynamic Particle Spectrometer (APS). It is found that the Cl/Na ratio in 50 nm NaCl + DA particles was negatively correlated with the DA concentration and positively correlated with the acidity coefficient of the DAs, i.e., the high DA mass fraction in particles and low the acidity coefficient of DAs results in strong heterogeneous reaction in the generation of these particles. The amplified sizes of NaCl + DA nanoparticles was also greatly influenced by the degree of the reaction involved. The Cl/Na ratio of NaCl + DA particles was found to have positive correlation with the amplified size of particles.
Zhibo Xie; Huaqiao Gui; Jiaoshi Zhang; Jiejie Bian; Xuejun Gu; Hang Xiao; Da-Ren Chen; Jianguo Liu. Heterogeneous reaction and condensation growth observation of NaCl/dicarboxylic acids nanoparticles by aerosol time-of-flight mass spectrometer with water-based particle size amplifier. Atmospheric Environment 2020, 246, 118162 .
AMA StyleZhibo Xie, Huaqiao Gui, Jiaoshi Zhang, Jiejie Bian, Xuejun Gu, Hang Xiao, Da-Ren Chen, Jianguo Liu. Heterogeneous reaction and condensation growth observation of NaCl/dicarboxylic acids nanoparticles by aerosol time-of-flight mass spectrometer with water-based particle size amplifier. Atmospheric Environment. 2020; 246 ():118162.
Chicago/Turabian StyleZhibo Xie; Huaqiao Gui; Jiaoshi Zhang; Jiejie Bian; Xuejun Gu; Hang Xiao; Da-Ren Chen; Jianguo Liu. 2020. "Heterogeneous reaction and condensation growth observation of NaCl/dicarboxylic acids nanoparticles by aerosol time-of-flight mass spectrometer with water-based particle size amplifier." Atmospheric Environment 246, no. : 118162.
Persistent wintertime heavy haze incidents caused by anthropogenic aerosols have repeatedly shrouded North China in recent years, while natural dust from the west and northwest of China also frequently affects air quality in this region. Through continuous observation by a multi-wavelength Raman lidar, here we found that wintertime aerosols in North China are typically characterized by a pronounced vertical stratification, where scattering nonspherical particles (dust or mixtures of dust and anthropogenic aerosols) dominated above the planetary boundary layer (PBL), and absorbing spherical particles (anthropogenic aerosols) prevailed within the PBL. This stratification is governed by meteorological conditions that strong northwesterly winds usually prevailed in the lower free troposphere, and southerly winds dominated in the PBL, producing persistent and intense haze pollution. With the increased contribution of elevated dust to the upper aerosols, the proportion of aerosol and trace gas at the surface in the whole column increased. Model results show that, besides directly deteriorating air quality, the key role of the elevated dust is to depress the development of PBL and weaken the turbulent exchange, mostly by lower level cooling and upper level heating, and it is more obvious during the dissipation stage, thus inhibiting the dissipation of heavy surface anthropogenic aerosols. The interactions of natural dust and anthropogenic aerosols under the unique topography of North China increase the surface anthropogenic aerosols and precursor gases, which may be one of the reasons why haze pollution in North China is heavier than that in other heavily polluted areas in China.
Zhuang Wang; Cheng Liu; Zhouqing Xie; Qihou Hu; Meinrat O. Andreae; Yunsheng Dong; Chun Zhao; Ting Liu; Yizhi Zhu; Haoran Liu; Chengzhi Xing; Wei Tan; Xiangguang Ji; Jinan Lin; Jianguo Liu. Elevated dust layers inhibit dissipation of heavy anthropogenic surface air pollution. Atmospheric Chemistry and Physics 2020, 20, 14917 -14932.
AMA StyleZhuang Wang, Cheng Liu, Zhouqing Xie, Qihou Hu, Meinrat O. Andreae, Yunsheng Dong, Chun Zhao, Ting Liu, Yizhi Zhu, Haoran Liu, Chengzhi Xing, Wei Tan, Xiangguang Ji, Jinan Lin, Jianguo Liu. Elevated dust layers inhibit dissipation of heavy anthropogenic surface air pollution. Atmospheric Chemistry and Physics. 2020; 20 (23):14917-14932.
Chicago/Turabian StyleZhuang Wang; Cheng Liu; Zhouqing Xie; Qihou Hu; Meinrat O. Andreae; Yunsheng Dong; Chun Zhao; Ting Liu; Yizhi Zhu; Haoran Liu; Chengzhi Xing; Wei Tan; Xiangguang Ji; Jinan Lin; Jianguo Liu. 2020. "Elevated dust layers inhibit dissipation of heavy anthropogenic surface air pollution." Atmospheric Chemistry and Physics 20, no. 23: 14917-14932.
We present an improved incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS) system based on an iterative retrieval algorithm for the simultaneous detection of atmospheric nitrous acid (HONO) and nitrogen dioxide (NO2). The conventional IBBCEAS retrieval algorithm depends on the absolute change in the light intensity, which requires high light source stability and the stable transmission of the light intensity of all optical components. The new algorithm has an iterative module to obtain the effective absorption optical path length, and the concentrations of HONO and NO2 are then determined by differential optical absorption spectroscopy (DOAS) retrieval; thus, the method is insensitive to the fluctuation in the absolute light intensity. The robustness of the system is verified by simulating the influence of the relative change in the light intensity on the spectral retrieval results. The effect of nitrogen purging in front of the cavity mirrors on shortening the actual cavity length was measured and corrected using NO2 gas samples. Allan deviation analysis was conducted to determine the system stability, and it indicated that the detection limits (2σ) of HONO and NO2 are 0.08 and 0.14 ppbv at an integration time of 60 s respectively. Furthermore, Kalman filtering was used to improve the measurement precision of the system. The measurement precision at an integration time of 3 s can be improved 4.5-fold by applying Kalman filtering, which is equivalent to the measurement precision at an integration time of 60 s without applying Kalman filtering. The atmospheric HONO and NO2 concentrations were observed by the IBBCEAS system based on an iterative algorithm and were compared with values measured by conventional IBBCEAS.
Ke Tang; Min Qin; Wu Fang; Jun Duan; Fanhao Meng; Kaidi Ye; Helu Zhang; Pinhua Xie; Yabai He; Wenbin Xu; Jianguo Liu; Wenqing Liu. Simultaneous detection of atmospheric HONO and NO2 utilising an IBBCEAS system based on an iterative algorithm. Atmospheric Measurement Techniques 2020, 13, 6487 -6499.
AMA StyleKe Tang, Min Qin, Wu Fang, Jun Duan, Fanhao Meng, Kaidi Ye, Helu Zhang, Pinhua Xie, Yabai He, Wenbin Xu, Jianguo Liu, Wenqing Liu. Simultaneous detection of atmospheric HONO and NO2 utilising an IBBCEAS system based on an iterative algorithm. Atmospheric Measurement Techniques. 2020; 13 (12):6487-6499.
Chicago/Turabian StyleKe Tang; Min Qin; Wu Fang; Jun Duan; Fanhao Meng; Kaidi Ye; Helu Zhang; Pinhua Xie; Yabai He; Wenbin Xu; Jianguo Liu; Wenqing Liu. 2020. "Simultaneous detection of atmospheric HONO and NO2 utilising an IBBCEAS system based on an iterative algorithm." Atmospheric Measurement Techniques 13, no. 12: 6487-6499.
We present an improved TROPOspheric Monitoring Instrument (TROPOMI) retrieval of formaldehyde (HCHO) over China. The new retrieval optimizes the slant column density (SCD) retrieval and air mass factor (AMF) calculation for TROPOMI observations of HCHO over China. Retrieval of HCHO differential SCDs (DSCDs) is improved using the basic optical differential spectroscopy (BOAS) technique resulting in lower noise and smaller random error, while AMFs are improved with a priori HCHO profiles from a higher resolution regional chemistry transport model. Compared to the operational product, the new TROPOMI HCHO retrieval shows better agreement with ground-based Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements in Beijing. The improvements are mainly related to the AMF calculation with more precise a priori profiles in winter. Using more precise a priori profiles in general reduces HCHO vertical column densities (VCDs) by 52.37 % (± 27.09 %) in winter. Considering the aerosol effect in AMF calculation reduces the operational product by 11.46 % (± 1.48 %) and our retrieval by 17.61 % (± 1.92 %) in winter. The improved and operational HCHO are also used to investigate the spatial–temporal characteristics of HCHO over China. The result shows that both improved and operational HCHO VCDs reach maximum in summer and minimum in winter. High HCHO VCDs mainly located over populated areas, i.e., Sichuan Basin and central and eastern China, indicate a significant contribution of anthropogenic emissions. The hotspots are more obvious on the map of the improved HCHO retrieval than the operational product. The result indicates that the improved TROPOMI HCHO retrieval is more suitable for the analysis of regional- and city-scale pollution in China.
Wenjing Su; Cheng Liu; Ka Lok Chan; Qihou Hu; Haoran Liu; Xiangguang Ji; Yizhi Zhu; Ting Liu; Chengxin Zhang; Yujia Chen; Jianguo Liu. An improved TROPOMI tropospheric HCHO retrieval over China. Atmospheric Measurement Techniques 2020, 13, 6271 -6292.
AMA StyleWenjing Su, Cheng Liu, Ka Lok Chan, Qihou Hu, Haoran Liu, Xiangguang Ji, Yizhi Zhu, Ting Liu, Chengxin Zhang, Yujia Chen, Jianguo Liu. An improved TROPOMI tropospheric HCHO retrieval over China. Atmospheric Measurement Techniques. 2020; 13 (11):6271-6292.
Chicago/Turabian StyleWenjing Su; Cheng Liu; Ka Lok Chan; Qihou Hu; Haoran Liu; Xiangguang Ji; Yizhi Zhu; Ting Liu; Chengxin Zhang; Yujia Chen; Jianguo Liu. 2020. "An improved TROPOMI tropospheric HCHO retrieval over China." Atmospheric Measurement Techniques 13, no. 11: 6271-6292.
The establishment and development of a set of methods of oil accurate recognition in a different environment are of great significance to the effective management of oil spill pollution. In this work, the concentration-emission matrix (CEM) is formed by introducing the concentration dimension. The principal component analysis (PCA) is applied to extract the spectral feature. The classification methods, such as Probabilistic Neural Networks (PNNs) and Genic Algorithm optimization Support Vector Machine (SVM) parameters (GA-SVM), are used for oil identification and the recognition accuracies of the two classification methods are compared. The results show that the GA-SVM combined with PCA has the highest recognition accuracy for different oils. The proposed approach has great potential in rapid and accurate oil source identification.
Yunan Chen; Ruifang Yang; Nanjing Zhao; Wei Zhu; Xiaowei Chen; Ruiqi Zhang; Jianguo Liu; Wenqing Liu. Concentration-Emission Matrix (CEM) Spectroscopy Combined with GA-SVM: An Analytical Method to Recognize Oil Species in Marine. Molecules 2020, 25, 5124 .
AMA StyleYunan Chen, Ruifang Yang, Nanjing Zhao, Wei Zhu, Xiaowei Chen, Ruiqi Zhang, Jianguo Liu, Wenqing Liu. Concentration-Emission Matrix (CEM) Spectroscopy Combined with GA-SVM: An Analytical Method to Recognize Oil Species in Marine. Molecules. 2020; 25 (21):5124.
Chicago/Turabian StyleYunan Chen; Ruifang Yang; Nanjing Zhao; Wei Zhu; Xiaowei Chen; Ruiqi Zhang; Jianguo Liu; Wenqing Liu. 2020. "Concentration-Emission Matrix (CEM) Spectroscopy Combined with GA-SVM: An Analytical Method to Recognize Oil Species in Marine." Molecules 25, no. 21: 5124.
Water vapor vertical profiles are important in numerical weather prediction, moisture transport, and vertical flux calculation. This study presents the Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) retrieval algorithm for water vapor vertical profiles and the retrieved results are validated with corresponding independent datasets under clear sky. The retrieved Vertical Column Densities (VCDs) and surface concentrations are validated with the Aerosol Robotic Network (AERONET) and National Climatic Data Centre (NCDC) datasets, achieving good correlation coefficients (R) of 0.922 and 0.876, respectively. The retrieved vertical profiles agree well with weekly balloon-borne radiosonde measurements. Furthermore, the retrieved water vapor concentrations at different altitudes (100–2000 m) are validated with the corresponding European Centre for Medium-range Weather Forecasts (ECMWF) ERA-interim datasets, achieving a correlation coefficient (R) varying from 0.695 to 0.857. The total error budgets for the surface concentrations and VCDs are 31% and 38%, respectively. Finally, the retrieval performance of the MAX-DOAS algorithm under different aerosol loads is evaluated. High aerosol loads obstruct the retrieval of surface concentrations and VCDs, with surface concentrations more liable to severe interference from such aerosol loads. To summarize, the feasibility of detecting water vapor profiles using MAX-DOAS under clear sky is confirmed in this work.
Hua Lin; Cheng Liu; Chengzhi Xing; Qihou Hu; Qianqian Hong; Haoran Liu; Qihua Li; Wei Tan; Xiangguang Ji; Zhuang Wang; Jianguo Liu. Validation of Water Vapor Vertical Distributions Retrieved from MAX-DOAS over Beijing, China. Remote Sensing 2020, 12, 3193 .
AMA StyleHua Lin, Cheng Liu, Chengzhi Xing, Qihou Hu, Qianqian Hong, Haoran Liu, Qihua Li, Wei Tan, Xiangguang Ji, Zhuang Wang, Jianguo Liu. Validation of Water Vapor Vertical Distributions Retrieved from MAX-DOAS over Beijing, China. Remote Sensing. 2020; 12 (19):3193.
Chicago/Turabian StyleHua Lin; Cheng Liu; Chengzhi Xing; Qihou Hu; Qianqian Hong; Haoran Liu; Qihua Li; Wei Tan; Xiangguang Ji; Zhuang Wang; Jianguo Liu. 2020. "Validation of Water Vapor Vertical Distributions Retrieved from MAX-DOAS over Beijing, China." Remote Sensing 12, no. 19: 3193.
In this paper, we present the Hefei EMI Cloud Retrieval Algorithm (HECORA), which uses information from the O2-O2 absorption band around 477 nm to retrieve effective cloud fraction and effective cloud pressure from satellite observations. The retrieved cloud information intends to improve the atmospheric trace gas products based on the Environment Monitoring Instrument (EMI) spectrometer. The HECORA method builds on OMCLDO2 and presents some evolutions. The Vector Linearized Discrete Ordinate Radiative Transfer (VLIDORT) model has been used to produce the Top of the Atmosphere (TOA) reflectance Look-up Tables (LUT) as a function of the cloud fraction and cloud pressure. Applying the Differential Optical Absorption Spectroscopy (DOAS) technique to the synthetic reflectance LUT, the reflectance spectra can be associated with O2-O2 geometrical vertical column densities (VCDgeo) and continuum reflectance. This is the core of the retrieval method, since there is a one-to-one relationship between O2-O2 VCDgeo and continuum reflectance, on the one hand, and effective cloud fraction and effective cloud pressure, on the other hand, for a given illumination and observing geometry and given surface height and surface albedo. We first used the VLIDORT synthetic spectra to verify the HECORA algorithm and obtained good results in both the Lambertian cloud model and the scattering cloud model. Secondly, HECORA is applied to OMI and TROPOMI and compared with OMCLDO2, FRESCO+, and OCRA/ROCINN cloud products. Later, the cloud pressure results from TROPOMI observations obtained using HECORA and FRESCO+ are compared with the CALIOP Cloud Layer product. HECORA is closer to the CALIOP results under low cloud conditions, while FRESCO+ is closer to high clouds due to the higher sensitivity of the O2 A-band to cloud vertical information. Finally, HECORA is applied to the TROPOMI NO2 retrieval. Validation of the tropospheric NO2 VCD with ground-based MAX-DOAS measurements shows that choosing HECORA cloud products to correct for photon path variations on the TROPOMI tropospheric NO2 VCD retrievals has better performance than using FRESCO+ under low cloud conditions. In conclusion, this paper shows that the HECORA cloud products are in good agreement with the well-established cloud products and that they are suitable for correcting the effect of cloud in trace gas retrievals. Therefore, HECORA has the potential to be applied to EMI.
Shuntian Wang; Cheng Liu; Wenqiang Zhang; Nan Hao; Sebastián Gimeno García; Chengzhi Xing; Chengxin Zhang; Wenjing Su; Jianguo Liu. Development and Application of HECORA Cloud Retrieval Algorithm Based On the O2-O2 477 nm Absorption Band. Remote Sensing 2020, 12, 3039 .
AMA StyleShuntian Wang, Cheng Liu, Wenqiang Zhang, Nan Hao, Sebastián Gimeno García, Chengzhi Xing, Chengxin Zhang, Wenjing Su, Jianguo Liu. Development and Application of HECORA Cloud Retrieval Algorithm Based On the O2-O2 477 nm Absorption Band. Remote Sensing. 2020; 12 (18):3039.
Chicago/Turabian StyleShuntian Wang; Cheng Liu; Wenqiang Zhang; Nan Hao; Sebastián Gimeno García; Chengzhi Xing; Chengxin Zhang; Wenjing Su; Jianguo Liu. 2020. "Development and Application of HECORA Cloud Retrieval Algorithm Based On the O2-O2 477 nm Absorption Band." Remote Sensing 12, no. 18: 3039.
Atmospheric pollutants over the Himalayas and Tibetan Plateau (HTP) have potential implications for accelerating the melting of glaciers, damaging air quality, water sources and grasslands, and threatening climate on regional and global scales. Improved knowledge of the variabilities, sources, drivers, and transport pathways of atmospheric pollutants over the HTP is significant for regulatory and control purpose. In this study, we first quantify the variability, source, and transport of CO over the HTP by using in situ measurement, GEOS-Chem model tagged CO simulation, and atmospheric circulation pattern techniques. Diurnal, seasonal, and interannual variability of CO over the HTP are investigated with ~ 6 years (January 2015 to July 2020) of surface CO measurements in eight cities over the HTP. Annual mean of surface CO volume mixing ratio (VMR) over the HTP varied over 318.3 ± 71.6 to 901.6 ± 472.2 ppbv, and a large seasonal cycle was observed with high levels of CO in the late autumn to spring and low levels of CO in summer to early autumn. The diurnal cycle is characterized by a bimodal pattern with two maximums in later morning and midnight, respectively. Surface CO VMR from 2015–2020 in most cities over the HTP showed negative trends. The in situ CO measurements are for the first time used to assess the performance of GEOS-Chem full-chemistry model for the specifics of the HTP. Generally, GEOS-Chem can capture the measured variability of low CO levels but shows large discrepancies in high CO levels. Distinct dependencies on a short lifetime species of NO2 almost in all cities over the HTP were observed, implying local emissions to be predominant. By turning off the emission inventories within the HTP in GEOS-Chem tagged CO simulation, the relative contribution of long range transport was evaluated. The results disclosed that transport ratios of primary anthropogenic source, primary biomass burning (BB) source, and secondary oxidation source to the surface CO VMR over the HTP varied over 35 to 61 %, 5 to 21 %, and 30 to 56 %, respectively. The anthropogenic contribution is dominated by the South Asia and East Asia (SEAS) region throughout the year (58 % to 91 %). The BB contribution is dominated by the SEAS region in spring (25 to 80 %) and the Africa (AF) region in July–February (30–70 %). This study concluded that the anthropogenic and oxidation sources originating either local or in SEAS region dominated the surface CO over the HTP, which is different from the black carbon that is mainly attributed to BB source from SEAS region. The decreasing trends in surface CO VMR since 2015 in most cities over the HTP are attributed to the reduction in local and transported CO emissions in recent years.
Youwen Sun; Hao Yin; Yuan Cheng; Qianggong Zhang; Bo Zheng; Justus Notholt; Xiao Lu; Cheng Liu; Yuan Tian; Jianguo Liu. Quantifying variability, source, and transport of CO over the Himalayas and Tibetan Plateau. 2020, 2020, 1 -29.
AMA StyleYouwen Sun, Hao Yin, Yuan Cheng, Qianggong Zhang, Bo Zheng, Justus Notholt, Xiao Lu, Cheng Liu, Yuan Tian, Jianguo Liu. Quantifying variability, source, and transport of CO over the Himalayas and Tibetan Plateau. . 2020; 2020 ():1-29.
Chicago/Turabian StyleYouwen Sun; Hao Yin; Yuan Cheng; Qianggong Zhang; Bo Zheng; Justus Notholt; Xiao Lu; Cheng Liu; Yuan Tian; Jianguo Liu. 2020. "Quantifying variability, source, and transport of CO over the Himalayas and Tibetan Plateau." 2020, no. : 1-29.
The major air pollutant emissions have decreased and the overall air quality has substantially improved across China in recent years as a consequence of active clean air policies for mitigating severe air pollution problems. As key precursors of formaldehyde (HCHO) and ozone (O3), the volatile organic compounds (VOCs) in China are still increasing because current clean air policies lack mitigation measures for VOCs. In this study, we mapped the drivers of HCHO variability over eastern China using ground-based high-resolution Fourier transform infrared (FTIR) spectrometry and GEOS-Chem model simulation. Diurnal, seasonal, and interannual variability of HCHO over eastern China was investigated and hydroxyl (OH) radical production from HCHO was evaluated. The relative contributions of emitted and photochemical sources to the observed HCHO were analysed by using ground level carbon monoxide (CO) and Ox (O3 + nitrogen oxide (NO2)) as tracers for emitted and photochemical HCHO, respectively. Contributions of various emission sectors and geographical transport to the observed HCHO summertime enhancements were determined by using a GEOS-Chem tagged-tracer simulation. The tropospheric HCHO volume mixing ratio (VMR) reached a maximum monthly mean value of (1.1 ± 0.27) ppbv in July and a minimum monthly mean value of (0.4 ± 0.11) ppbv in January. The tropospheric HCHO VMR time series from 2015–2019 shows a positive trend of (1.43 ± 0.14) % per yr. The photochemical HCHO is the dominant source of atmospheric HCHO over eastern China for most of the year (68.1 %). In the studied years, the HCHO photolysis was an important source of OH radical over eastern China during all sunlight hours of both summer and winter days. The anthropogenic emissions (fossil fuel + biofuel emissions) accounted for 31.96 % and the natural emissions (biomass burning + biogenic) accounted for 48.75 % of HCHO summertime enhancements. The observed HCHO summertime enhancements were largely attributed to the emissions within China (76.92 %), where eastern China dominated the contribution (46.24 %). The increased trend in HCHO in recent years was largely attributed to the increase in the HCHO precursors such as CH4 and nonmethane VOCs (NMVOCs). This study can provide an evaluation of recent VOC emissions and regional photochemical capacity in China. In addition, this study is also important for regulatory and control purposes and will help to improve urban air quality and contribute to the formation of new Chinese clean air policies in the future.
Youwen Sun; Hao Yin; Cheng Liu; Lin Zhang; Yuan Cheng; Mathias Palm; Justus Notholt; Xiao Lu; Corinne Vigouroux; Bo Zheng; Wei Wang; Nicholas Jones; Changong Shan; Yuan Tian; Qihou Hu; Jianguo Liu. Mapping the drivers of formaldehyde (HCHO) variability from 2015–2019 over eastern China: insights from FTIR observation and GEOS-Chem model simulation. 2020, 2020, 1 -24.
AMA StyleYouwen Sun, Hao Yin, Cheng Liu, Lin Zhang, Yuan Cheng, Mathias Palm, Justus Notholt, Xiao Lu, Corinne Vigouroux, Bo Zheng, Wei Wang, Nicholas Jones, Changong Shan, Yuan Tian, Qihou Hu, Jianguo Liu. Mapping the drivers of formaldehyde (HCHO) variability from 2015–2019 over eastern China: insights from FTIR observation and GEOS-Chem model simulation. . 2020; 2020 ():1-24.
Chicago/Turabian StyleYouwen Sun; Hao Yin; Cheng Liu; Lin Zhang; Yuan Cheng; Mathias Palm; Justus Notholt; Xiao Lu; Corinne Vigouroux; Bo Zheng; Wei Wang; Nicholas Jones; Changong Shan; Yuan Tian; Qihou Hu; Jianguo Liu. 2020. "Mapping the drivers of formaldehyde (HCHO) variability from 2015–2019 over eastern China: insights from FTIR observation and GEOS-Chem model simulation." 2020, no. : 1-24.