Assessment of the Performance of TROPOMI NO2 and SO2 Data Products in the North China Plain: Comparison, Correction and Application

The TROPOspheric Monitoring Instrument (TROPOMI) aboard the Sentinel-5 Precursor satellite has been used to detect the atmospheric environment since 2017, and it is of great significance to investigate the accuracy of its products. In this work, we present comparisons between TROPOMI tropospheric NO2 and total SO2 products against ground-based MAX-DOAS at a single site (Xianghe) and OMI products over a seriously polluted region (North China Plain, NCP) in China. The results show that both NO2 and SO2 data from three datasets exhibit a similar tendency and seasonality. In addition, TROPOMI tropospheric NO2 columns are generally underestimated compared with collocated MAX-DOAS and OMI data by about 30–60%. In contrast to NO2, the monthly average SO2 retrieved from TROPOMI is larger than MAX-DOAS and OMI, with a mean bias of 2.41 (153.8%) and 2.17 × 1016 molec cm−2 (120.7%), respectively. All the results demonstrated that the TROPOMI NO2 as well as the SO2 algorithms need to be further improved. Thus, to ensure reliable analysis in NCP area, a correction method has been proposed and applied to TROPOMI Level 3 data. The revised datasets agree reasonably well with OMI observations (R > 0.95 for NO2, and R > 0.85 for SO2) over the NCP region and have smaller mean biases with MAX-DOAS. In the application during COVID-19 pandemic, it showed that the NO2 column in January-April 2020 decreased by almost 25–45% compared to the same period in 2019 due to the lockdown for COVID-19, and there was an apparent rebound of nearly 15–50% during 2021. In contrast, a marginal change of the corresponding SO2 is revealed in the NCP region. It signifies that short-term control measures are expected to have more effects on NO2 reduction than SO2; conversely, we need to recognize that although the COVID-19 lockdown measures improved air quality in the short term, the pollution status will rebound to its previous level once industrial and human activities return to normal.

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Decreased gaseous carbonyls in the North China plain from 2004 to 2017 and future control measures

Atmospheric Environment ◽

10.1016/j.atmosenv.2019.117015 ◽

2019 ◽

Vol 218 ◽

pp. 117015 ◽

Cited By ~ 2

Author(s):

Guiqian Tang ◽

Xi Chen ◽

Xingru Li ◽

Yinghong Wang ◽

Yuan Yang ◽

...

Keyword(s):

North China Plain ◽

North China ◽

Control Measures ◽

The North ◽

The North China Plain

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Validation of OMI tropospheric NO2 column data using MAX-DOAS measurements deep inside the North China Plain in June 2006

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-8-8243-2008 ◽

2008 ◽

Vol 8 (2) ◽

pp. 8243-8271 ◽

Cited By ~ 3

Author(s):

H. Irie ◽

Y. Kanaya ◽

H. Akimoto ◽

H. Tanimoto ◽

Z. Wang ◽

...

Keyword(s):

North China Plain ◽

North China ◽

Optical Absorption Spectroscopy ◽

Ozone Monitoring Instrument ◽

The North ◽

The North China Plain ◽

Standard Product ◽

The Us ◽

Tropospheric No2 ◽

Independent Observations

Abstract. A challenge for the quantitative analysis of tropospheric nitrogen dioxide (NO2) column data from satellite observations is posed mainly by the lack of satellite-independent observations for validation. We performed such observations of the tropospheric NO2 column using the ground-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) technique in the North China Plain (NCP) from 29 May to 29 June 2006. Comparisons between tropospheric NO2 columns measured by MAX-DOAS and the Ozone Monitoring Instrument (OMI) onboard the Aura satellite indicate that OMI data (the standard product, version 3) over NCP may have a positive bias of 1.6×1015 molecules cm−2 (20%), where the estimated random error in the OMI data is 0.6×1015 molecules cm−2 or approximately 8%. Combining these results with literature validation results for the US, Europe, and Pacific Ocean suggests that a bias of +20%/–30% is a reasonable estimate, accounting for different regions. Considering the uncertainty estimated here will pave the way for quantitative studies using OMI NO2 data, especially over NCP.

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Nitrate-driven urban haze pollution during summertime over the North China Plain

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-5293-2018 ◽

2018 ◽

Vol 18 (8) ◽

pp. 5293-5306 ◽

Cited By ~ 55

Author(s):

Haiyan Li ◽

Qiang Zhang ◽

Bo Zheng ◽

Chunrong Chen ◽

Nana Wu ◽

...

Keyword(s):

North China Plain ◽

North China ◽

Organic Aerosol ◽

Control Measures ◽

Public Attention ◽

The North ◽

The North China Plain ◽

Nitrate Production ◽

Haze Pollution ◽

Aerosol Pollution

Abstract. Compared to the severe winter haze episodes in the North China Plain (NCP), haze pollution during summertime has drawn little public attention. In this study, we present the highly time-resolved chemical composition of submicron particles (PM1) measured in Beijing and Xinxiang in the NCP region during summertime to evaluate the driving factors of aerosol pollution. During the campaign periods (30 June to 27 July 2015, for Beijing and 8 to 25 June 2017, for Xinxiang), the average PM1 concentrations were 35.0 and 64.2 µg m−3 in Beijing and Xinxiang. Pollution episodes characterized with largely enhanced nitrate concentrations were observed at both sites. In contrast to the slightly decreased mass fractions of sulfate, semivolatile oxygenated organic aerosol (SV-OOA), and low-volatility oxygenated organic aerosol (LV-OOA) in PM1, nitrate displayed a significantly enhanced contribution with the aggravation of aerosol pollution, highlighting the importance of nitrate formation as the driving force of haze evolution in summer. Rapid nitrate production mainly occurred after midnight, with a higher formation rate than that of sulfate, SV-OOA, or LV-OOA. Based on observation measurements and thermodynamic modeling, high ammonia emissions in the NCP region favored the high nitrate production in summer. Nighttime nitrate formation through heterogeneous hydrolysis of dinitrogen pentoxide (N2O5) enhanced with the development of haze pollution. In addition, air masses from surrounding polluted areas during haze episodes led to more nitrate production. Finally, atmospheric particulate nitrate data acquired by mass spectrometric techniques from various field campaigns in Asia, Europe, and North America uncovered a higher concentration and higher fraction of nitrate present in China. Although measurements in Beijing during different years demonstrate a decline in the nitrate concentration in recent years, the nitrate contribution in PM1 still remains high. To effectively alleviate particulate matter pollution in summer, our results suggest an urgent need to initiate ammonia emission control measures and further reduce nitrogen oxide emissions over the NCP region.

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Nitrate-driven haze pollution during summertime over the North China Plain

10.5194/acp-2017-1156 ◽

2018 ◽

Author(s):

Haiyan Li ◽

Qiang Zhang ◽

Bo Zheng ◽

Chunrong Chen ◽

Nana Wu ◽

...

Keyword(s):

North China Plain ◽

North China ◽

Organic Aerosol ◽

Control Measures ◽

Public Attention ◽

The North ◽

The North China Plain ◽

Nitrate Production ◽

Haze Pollution ◽

Aerosol Pollution

Abstract. Compared to the severe winter haze episodes in the North China Plain (NCP), haze pollution during summertime has drawn little public attention. In this study, we present the highly time-resolved chemical composition of submicron particles (PM1) measured in Beijing and Xinxiang in the NCP region during summertime to evaluate the driving factors of aerosol pollution. During the campaign periods (30 June to 27 July, 2015, for Beijing and 8 to 25 June, 2017, for Xinxiang), the average PM1 concentrations were 35.0 μg m−3 and 64.2 μg m−3 in Beijing and Xinxiang, respectively. Pollution episodes characterized with largely enhanced nitrate concentrations were observed at both sites. In contrast to the slightly decreased mass fractions of sulfate, semi-volatile oxygenated organic aerosol (SV-OOA), and low-volatile oxygenated organic aerosol (LV-OOA) in PM1, nitrate displayed an almost linearly increased contribution with the aggravation of aerosol pollution in both Beijing and Xinxiang, highlighting the importance of nitrate formation as the driving force of haze evolution in summer. Rapid nitrate production mainly occurred after midnight, with a higher formation rate than that of sulfate, SV-OOA, or LV-OOA. Detailed investigation of nitrate behaviors revealed several factors influencing the rapid nitrate formation in summer: high ammonia emissions in the NCP region, the gas-to-particle equilibrium of ammonium nitrate closely related to variations in temperature and relative humidity, nighttime nitrate production through heterogeneous hydrolysis of dinitrogen pentoxide (N2O5), and regional transport from different air mass origins. Finally, atmospheric particulate nitrate data acquired by mass spectrometric techniques from various field campaigns in Asia, Europe, and North America uncovered a higher concentration and higher fraction of nitrate present in China. Although measurements in Beijing during different years demonstrate a decline in the nitrate concentration in recent years, the nitrate contribution in PM1 still remains high. To effectively alleviate particulate matter pollution in summer, our results call for the urgent need to initiate ammonia emission control measures and further reduce nitrogen oxide emissions over the NCP region.

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Validation of OMI tropospheric NO2 column data using MAX-DOAS measurements deep inside the North China Plain in June 2006: Mount Tai Experiment 2006

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-6577-2008 ◽

2008 ◽

Vol 8 (22) ◽

pp. 6577-6586 ◽

Cited By ~ 79

Author(s):

H. Irie ◽

Y. Kanaya ◽

H. Akimoto ◽

H. Tanimoto ◽

Z. Wang ◽

...

Keyword(s):

North China Plain ◽

North China ◽

Optical Absorption Spectroscopy ◽

Ozone Monitoring Instrument ◽

The North ◽

The North China Plain ◽

Standard Product ◽

The Us ◽

Tropospheric No2 ◽

Independent Observations

Abstract. A challenge for the quantitative analysis of tropospheric nitrogen dioxide (NO2) column data from satellite observations is posed partly by the lack of satellite-independent observations for validation. We performed such observations of the tropospheric NO2 column using the ground-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) technique in the North China Plain (NCP) from 29 May to 29 June, 2006. Comparisons between tropospheric NO2 columns measured by MAX-DOAS and the Ozone Monitoring Instrument (OMI) onboard the Aura satellite indicate that OMI data (the standard product, version 3) over NCP may have a positive bias of 1.6×1015 molecules cm−2 (20%), yet within the uncertainty of the OMI data. Combining these results with literature validation results for the US, Europe, and Pacific Ocean suggests that a bias of +20%/−30% is a reasonable estimate, accounting for different regions.

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Long distance mobile MAX-DOAS observation of NO2 and SO2 over the North China Plain, and identification of regional transport and emission of power plant

10.5194/egusphere-egu2020-1823 ◽

2020 ◽

Author(s):

Wei Tan ◽

Cheng Liu ◽

Shanshan Wang ◽

Haoran Liu ◽

Yizhi Zhu ◽

...

Keyword(s):

Power Plant ◽

Power Plants ◽

North China Plain ◽

North China ◽

Anhui Province ◽

Atmospheric Environment ◽

Long Distance ◽

The North ◽

The North China Plain ◽

Emission Fluxes

In this study, the spatial-temporal distribution of the NO2 and SO2 Vertical Columns Densities (VCDs) in the North China Plain (NCP) region was achieved by the long-distance mobile measurements using the mobile Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) instrument. The mobile observations were taken in both summer (July 2017) and winter (January and February 2018) and the total driving mileage exceeded 3000 km. The concentrations of NO2 and SO2 pollution in different seasons and places were significantly different. During winter observations, the serious NO2 and SO2 pollution were both observed in northern Anhui province, central Shandong province, and the Beijing-Tianjin-Hebei Region. The evolution and transportation process of the three typical heavy pollution cases were discussed in detail. Combined with the WRF-chem simulated wind field information, the NO2 transportation flux from the northern Jiangsu province to the northern Anhui province was quantified to be 7.12 kg s-1. Finally, we estimated the NO2 and SO2 emissions from the Dezhou and Hengshui power plants by the plume cross section scanning observation and encircled observation methods, respectively. The NO2 and SO2 emission fluxes of the Dezhou power plant are 0.79 and 1.11 kg s-1, while the NO2 and SO2 emission fluxes of the Hengshui power plant are 0.12 and 0.36 kg s-1. This study has quantitatively analyzed the transportations of atmospheric pollutants and emissions of power plants, which is helpful to understand the occurrence and evolution of pollution and also useful for the government to put forward some policies to protect and control the atmospheric environment.

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Tropospheric NO2 Pollution Monitoring with the GF-5 Satellite Environmental Trace Gases Monitoring Instrument over the North China Plain during Winter 2018–2019

Atmosphere ◽

10.3390/atmos12030398 ◽

2021 ◽

Vol 12 (3) ◽

pp. 398

Author(s):

Dongshang Yang ◽

Yuhan Luo ◽

Yi Zeng ◽

Fuqi Si ◽

Liang Xi ◽

...

Keyword(s):

North China Plain ◽

North China ◽

Trace Gases ◽

Pollution Monitoring ◽

Optical Absorption Spectroscopy ◽

Monitoring Instrument ◽

The North ◽

The North China Plain ◽

Cross Correlation Analysis ◽

Tropospheric No2

The Environmental Trace Gases Monitoring Instrument (EMI) is a high-spectral-resolution payload onboard the latest pathfinder mission GaoFen-5, designed specifically for the monitoring of global atmospheric trace gas compositions and trends. This study describes a comparative analysis of the tropospheric nitrogen dioxide (NO2) columns over the North China Plain (NCP) from November 2018 to April 2019 based on EMI products. Validation of satellite products based on a cross-correlation analysis with data from four ground-based multi-axis differential optical absorption spectroscopy sites provided good correlation coefficients (r) ranging from 0.78 to 0.88. The distribution and monthly averaged tropospheric NO2 columns revealed high pollution exposure levels during winter (November–January) and a decrease from February onward in the NCP. Moreover, a typical pollution event was analyzed in detail in combination with wind field statistics. The results indicated that variations of NO2 concentrations in Beijing and Tianjin were highly correlated with the wind direction from 22.5–45.0 degrees west of south, especially during times of high NO2 amounts. These findings highlight that the EMI payload on the GaoFen-5 (GF-5) satellite is useful for remote sensing of regional and global NO2 detection.

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