Reconciling the bottom-up methodology and ground measurement constraints to improve the city-scale NMVOCs emission inventory: A case study of Nanjing, China

Wu, Rongrong; Zhao, Yu; Xia, Sijia; Hu, Wei; Xie, Fusheng; Zhang, Yan; Sun, Jing; Yu, Huan; An, Junling; Wang, Yutong

doi:10.1016/j.scitotenv.2021.152447

Cited by 8 publications

(5 citation statements)

References 43 publications

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“…Unfortunately, only the comprehensive results of isotopic source apportionment in Beijing are available at present and cannot be directly used to estimate nonagricultural NH 3 emissions for the whole of China. Because the sources of CO are relatively well defined than those of other pollutants and the uncertainty is lower, CO is frequently used as a reference compound to indicate emissions of other pollutants by the emission ratio method. − Additionally, previous studies revealed significantly positive correlations between CO emissions and NH 3 emissions from various nonagricultural sectors (Text S1). ,− Furthermore, we also found that there were positive correlations between CO and isotope-corrected NH 3 emissions from various nonagricultural sectors in Beijing (Figure S3).…”

Section: Materials and Methodsmentioning

confidence: 99%

Significant Increase in Ammonia Emissions in China: Considering Nonagricultural Sectors Based on Isotopic Source Apportionment

Yan,

Chen,

Wang

et al. 2024

Environ. Sci. Technol.

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Isotopic source apportionment results revealed that nonagricultural sectors are significant sources of ammonia (NH 3 ) emissions, particularly in urban areas. Unfortunately, nonagricultural sources have been substantially underrepresented in the current anthropogenic NH 3 emission inventories (EIs). Here, we propose a novel approach to develop a gridded EI of nonagricultural NH 3 in China for 2016 using a combination of isotopic source apportionment results and the emission ratios of carbon monoxide (CO) and NH 3 . We estimated that isotope-corrected nonagricultural NH 3 emissions were 4370 Gg in China in 2016, accounting for an increase in the total NH 3 emissions from 7 to 31%. As a result, compared to the original NH 3 EI, the annual emissions of total NH 3 increased by 35%. Thus, in comparison to the simulation driven by the original NH 3 EI, the WRF-Chem model driven by the isotope-corrected NH 3 EI has reduced the model biases in the surface concentrations and dry deposition flux of reduced nitrogen (NH x = gaseous NH 3 + particulate NH 4 + ) by 23 and 31%, respectively. This study may have wide-ranging implications for formulating targeted strategies for nonagricultural NH 3 emissions controls, making it facilitate the achievement of simultaneously alleviating nitrogen deposition and atmospheric pollution in the future.

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Section: Materials and Methodsmentioning

confidence: 99%

Significant Increase in Ammonia Emissions in China: Considering Nonagricultural Sectors Based on Isotopic Source Apportionment

Yan,

Chen,

Wang

et al. 2024

Environ. Sci. Technol.

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“…In China, notable discrepancies in aromatics have been observed between CMAQ predictions and measurements (Wang et al, 2020). Wu et al (2022) reconciled the bottom-up methodology and measurement constraints to improve the city-scale non-methane VOCs (NMVOCs) emission inventory in Nanjing, resulting in improved O3 simulation performance with the CMAQ model.…”

Section: Introductionmentioning

confidence: 93%

“…To evaluate the impact of these biases on O3 predictions, we modified the VOCs emissions of the MEIC based on the differences between observations and predictions. Previous studies have adjusted emission inventories to match observed constraints for predicting VOCs and O3 in specific cities (Wu et al, 2022;Wang et al, 2020). Considering the temporal and spatial variability of the 28 sites, we calculated the median ratio of VOCs for the 18 urban sites.…”

Section: Model Performance Evaluationmentioning

confidence: 99%

Current status of model predictions on volatile organic compounds and impacts on surface ozone predictions during summer in China

She

Lyu

et al. 2023

Preprint

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Abstract. Volatile organic compounds (VOCs) play a crucial role in the formation of tropospheric ozone (O3) and secondary organic aerosols. VOC emissions are generally considered to have larger uncertainties compared to other pollutants, such as sulphur dioxide and fine particulate matter (PM2.5). Although predictions of O3 and PM2.5 have been extensively evaluated in air quality modelling studies, there has been limited reporting on the evaluation of VOCs, mainly due to a lack of routine VOCs measurements at multiple sites. In this study, we utilized VOCs measurements from the ATMSYC project at 28 sites across China and assessed the predicted VOCs concentrations using the Community Multiscale Air Quality (CMAQ) model with the widely used Multi-resolution Emission Inventory for China (MEIC). The ratio of predicted to observed total VOCs was found to be 0.74 ± 0.40, with underpredictions ranging from 2.05 to 50.61 ppbv (5.77 % to 85.40 %) at 24 sites. A greater bias in VOCs predictions was observed in industrial cities in the north and southwest, such as Jinan, Shijiazhuang, Lanzhou, Chengdu, and Guiyang. In terms of different VOC components, alkanes, alkenes, non-naphthalene aromatics (ARO2MN), and alkynes were consistently underpredicted, with prediction to observation ratios of 0.53 ± 0.38, 0.51 ± 0.48, 0.31 ± 0.38, and 0.41 ± 0.47, respectively. Sensitivity experiments were conducted to assess the impact of the VOCs prediction bias on O3 predictions. While emission adjustments improved the model performance for VOCs, resulting in a ratio of total VOCs to 0.86 ± 0.47, they also exacerbated O3 overprediction relative to the base case by 0.62 % to 6.27 % across the sites. This study demonstrates that current modelling setups and emission inventories are likely to underpredict VOCs concentrations, and this underprediction of VOCs contributes to lower O3 predictions in China.

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“…Some other measures were identified to be important drivers of emission reduction, including control on mobile sources (e.g., implementation of the China Ⅴ emission standard for on-road vehicles) and replacement with low-VOCs paints. In our recent studies, we evaluated the average removal efficiency of AVOCs in industrial sector was less than 30% (Zhang et al, 2021a), and organic solvents with low-VOCs content accounted for less than 30% of total solvent use (Wu et al, 2022). Therefore, there would still be great potential for further reduction of AVOCs emissions through improvement on the end-of-pipe emission controls and use of cleaner solvents.…”

Section: Analysis Of Driving Force Of Emission Change From 2015 To 2019mentioning

confidence: 99%

“…In this study, therefore, we took Jiangsu as an example to demonstrate the development of high-resolution emission inventory and its application on evaluating the effectiveness of emission control actions. We integrated the methodological improvements on regional emission inventory by our previous studies (Zhou et al, 2017;Zhao et al, 2017;Wu et al, 2022;Zhang et al, 2019b;Zhang et al, 2020;, and compiled and incorporated best available facility-level information and real-world emission measurements (see details in the methodology and data section).…”

Section: Introductionmentioning

confidence: 99%

High-resolution regional emission inventory contributes to the evaluation of policy effectiveness: A case study in Jiangsu province, China

Zhang

et al. 2022

Preprint

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Abstract. China has been conducting a series of actions on air quality improvement for the past decades, and air pollutant emissions have been changing swiftly across the country. Province is an important administrative unit for air quality management, thus reliable provincial-level emission inventory for multiple years is essential for detecting the varying sources of pollution and evaluating the effectiveness of emission controls. In this study, we selected Jiangsu, one of the most developed provinces in China, and developed the high-resolution emission inventory of nine species for 2015–2019, with improved methodologies for different emission sectors, best available facility-level information on individual sources, and real-world emission measurements. Resulting from implementation of strict emission control measures, the anthropogenic emissions were estimated to have declined 53 %, 20 %, 7 %, 2 %, 10 %, 21 %, 16 %, 6 % and 18 % for SO2, NOX, CO, NMVOCs, NH3, PM10, PM2.5, BC, and OC from 2015 to 2019, respectively. Larger abatement of SO2, NOX and PM2.5 emissions were detected for the more developed southern Jiangsu. Since 2016, the ratio of biogenic volatile organic compounds (BVOCs) to anthropogenic volatile organic compounds (AVOCs) exceeded 50 % in July, indicating the importance of biogenic sources on summer O3 formation. Our estimates in annual emissions of NOX, NMVOCs, and NH3 were generally smaller than the national emission inventory MEIC, but larger for primary particles. The discrepancies between studies resulted mainly from different methods of emission estimation (e.g., the procedure-based approach for AVOCs emissions from key industries used in this work) and inconsistent information of emission source operation (e.g., the penetrations and removal efficiencies of air pollution control devices). Regarding the different periods, more reduction of SO2 emissions was found between 2015 and 2017, but NOX, AVOCs and PM2.5 between 2017 and 2019. Among the selected 13 major measures, the ultra-low emission retrofit on power sector was the most important contributor to the reduced SO2 and NOX emissions (accounting for 38 % and 43 % of the emission abatement, respectively) for 2015–2017, but its effect became very limited afterwards as the retrofit had been commonly completed by 2017. Instead, extensive management of coal-fired boilers and upgradation and renovation of non-electrical industry were the most important measures for 2017–2019, accounted collectively for 61 %, 49 % and 57 % reduction of SO2, NOX and PM2.5, respectively. Controls on key industrial sectors maintained the most effective for AVOCs reduction for the two periods, while measures on other sources (transportation and solvent replacement) became increasingly important for more recent years. Our provincial emission inventory was demonstrated to be supportive for high-resolution air quality modeling for multiple years. Through scenario setting and modeling, worsened meteorological conditions were found from 2015 to 2019 for PM2.5 and O3 pollution alleviation. However, the efforts on emission controls were identified to largely overcome the negative influence of meteorological variation. The changed anthropogenic emissions were estimated to contribute 4.3 and 5.5 μg·m-3 of PM2.5 concentration reduction for 2015–2017 and 2017–2019, respectively. While elevated O3 by 4.9 μg·m-3 for 2015–2017, the changing emissions led to 3.1 μg·m-3 of reduction for 2017–2019, partly (not fully though) offsetting the meteorology-driven growth. The analysis justified the validity of local emission control efforts on air quality improvement, and provided scientific basis to formulate air pollution prevention and control policies for other developed regions in China and worldwide.

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Reconciling the bottom-up methodology and ground measurement constraints to improve the city-scale NMVOCs emission inventory: A case study of Nanjing, China

Cited by 8 publications

References 43 publications

Significant Increase in Ammonia Emissions in China: Considering Nonagricultural Sectors Based on Isotopic Source Apportionment

Significant Increase in Ammonia Emissions in China: Considering Nonagricultural Sectors Based on Isotopic Source Apportionment

Current status of model predictions on volatile organic compounds and impacts on surface ozone predictions during summer in China

High-resolution regional emission inventory contributes to the evaluation of policy effectiveness: A case study in Jiangsu province, China

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