scholarly journals Temporal Analysis of OMI-Observed Tropospheric NO2 Columns over East Asia during 2006–2015

Atmosphere ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 658 ◽  
Author(s):  
Kyung M. Han
Keyword(s):  
South Korea ◽  
East Asia ◽  
Temporal Analysis ◽  
Temporal Variations ◽  
Policy Support ◽  
Northwestern Pacific ◽  
Nox Emissions ◽  
Ozone Monitoring Instrument ◽  
Transportation Sector ◽  
Monitoring Service

The study analyzed temporal variations of Ozone Monitoring Instrument (OMI)-observed NO2 columns, interregional correlation, and comparison between NO2 columns and NOx emissions during the period from 2006 to 2015. Regarding the trend of the NO2 columns, the linear lines were classified into four groups: (1) ‘upward and downward’ over six defined geographic regions in central-east Asia; (2) ‘downward’ over Guangzhou, Japan, and Taiwan; (3) ‘stagnant’ over South Korea; and (4) ‘upward’ over North Korea, Mongolia, Qinghai, and Northwestern Pacific ocean. In particular, the levels of NO2 columns in 2015 returned to those in 2006 over most of the polluted regions in China. Quantitatively, their relative changes in 2015 compared to 2006 were approximately 10%. From the interregional correlation analysis, it was found that unlike positive relationships between the polluted areas, the different variations of monthly NO2 columns led to negative relationships in Mongolia and Qinghai. Regarding the comparison between NO2 columns and NOx emission, the NOx emissions from the Copernicus Atmosphere Monitoring Service (CAMS) and Clean Air Policy Support System (CAPSS) inventories did not follow the year-to-year variations of NO2 columns over the polluted regions. In addition, the weekly effect was only clearly shown in South Korea, Japan, and Taiwan, indicating that the amounts of NOx emissions are significantly contributed to by the transportation sector.

scholarly journals Investigation of NO<sub>x</sub> emissions and NO<sub>x</sub>-related chemistry in East Asia using CMAQ-predicted and GOME-derived NO<sub>2</sub> columns

2009 ◽  
Vol 9 (3) ◽  
pp. 1017-1036 ◽  
Author(s):  
K. M. Han ◽  
C. H. Song ◽  
H. J. Ahn ◽  
R. S. Park ◽  
J. H. Woo ◽  
...  
Keyword(s):  
South Korea ◽  
East Asia ◽  
Seasonal Variations ◽  
North China ◽  
Emission Inventory ◽  
Nox Emission ◽  
Policy Support ◽  
Asia Pacific ◽  
Nox Emissions ◽  
Loss Rates

Abstract. In this study, NO2 columns from the US EPA Models-3/CMAQ model simulations carried out using the 2001 ACE-ASIA (Asia Pacific Regional Aerosol Characterization Experiment) emission inventory over East Asia were compared with the GOME-derived NO2 columns. There were large discrepancies between the CMAQ-predicted and GOME-derived NO2 columns in the fall and winter seasons. In particular, while the CMAQ-predicted NO2 columns produced larger values than the GOME-derived NO2 columns over South Korea for all four seasons, the CMAQ-predicted NO2 columns produced smaller values than the GOME-derived NO2 columns over North China for all seasons with the exception of summer (summer anomaly). It is believed that there might be some error in the NOx emission estimates as well as uncertainty in the NOx chemical loss rates over North China and South Korea. Regarding the latter, this study further focused on the biogenic VOC (BVOC) emissions that were strongly coupled with NOx chemistry during summer in East Asia. This study also investigated whether the CMAQ-modeled NO2/NOx ratios with the possibly overestimated isoprene emissions were higher than those with reduced isoprene emissions. Although changes in both the NOx chemical loss rates and NO2/NOx ratios from CMAQ-modeling with the different isoprene emissions affected the CMAQ-modeled NO2 levels, the effects were found to be limited, mainly due to the low absolute levels of NO2 in summer. Seasonal variations of the NOx emission fluxes over East Asia were further investigated by a set of sensitivity runs of the CMAQ model. Although the results still exhibited the summer anomaly possibly due to the uncertainties in both NOx-related chemistry in the CMAQ model and the GOME measurements, it is believed that consideration of both the seasonal variations in NOx emissions and the correct BVOC emissions in East Asia are critical. Overall, it is estimated that the NOx emissions are underestimated by ~57.3% in North China and overestimated by ~46.1% in South Korea over an entire year. In order to confirm the uncertainty in NOx emissions, the NOx emissions over South Korea and China were further investigated using the ACE-ASIA, REAS (Regional Emission inventory in ASia), and CAPSS (Clean Air Policy Support System) emission inventories. The comparison between the CMAQ-calculated and GOME-derived NO2 columns indicated that both the ACE-ASIA and REAS inventories have some uncertainty in NOx emissions over North China and South Korea, which can also lead to some errors in modeling the formation of ozone and secondary aerosols in South Korea and North China.

scholarly journals Investigation of NO<sub>x</sub> emissions and NO<sub>x</sub>-related chemistry in East Asia using CMAQ-predicted and GOME-derived NO<sub>2</sub> columns

2008 ◽  
Vol 8 (5) ◽  
pp. 17297-17341
Author(s):  
K. M. Han ◽  
C. H. Song ◽  
H. J. Ahn ◽  
C. K. Lee ◽  
A. Richter ◽  
...  
Keyword(s):  
South Korea ◽  
East Asia ◽  
North China ◽  
Emission Inventory ◽  
Estimation Error ◽  
Policy Support ◽  
Environmental Research ◽  
Asia Pacific ◽  
Nox Emissions ◽  
Loss Rates

Abstract. This study examined the estimation accuracy of NOx emissions over East Asia with particular focus on North China and South Korea due to their strong source (North China)-receptor (South Korea) relationship. In order to determine contributions of North China emissions to South Korean air quality accurately, it is important to examine the accuracy of the emission inventories of both regions. In this study, NO2 columns from the US EPA Models-3/CMAQ model simulations carried out using the 2001 ACE-ASIA (Asia Pacific Regional Aerosol Characterization Experiment) emission inventory over East Asia were compared with the GOME-derived NO2 columns. There were large discrepancies between the CMAQ-predicted and GOME-derived NO2 columns in the fall and winter seasons. In particular, while the CMAQ-predicted NO2 columns produced larger values than the GOME-derived NO2 columns over South Korea (receptor region) for all four seasons, the CMAQ-predicted NO2 columns produced smaller values than the GOME-derived NO2 columns over North China (source region) for all seasons with the exception of summer. It is believed that there might be some estimation error in the NOx emissions as well as large uncertainty in NOx loss rates over North China and South Korea. Regarding the latter, this study further focused on the biogenic VOC emissions that were strongly coupled with NOx chemistry in East Asia. It was found that the rates of NOx loss determined by CMAQ modeling studies might be significantly low due to the possible overestimation of biogenic isoprene emissions during summer, particularly in China. In addition, due to the possible overestimation of isoprene emissions, the CMAQ-modeled NO2/NOx ratios might show an incorrectly high level, compared with the actual NO2/NOx ratios. In addition to the retarded NOx chemical loss rates and overestimated NO2/NOx ratios, the omission of soil NOx emissions over North China during summer can lead to an underestimation of NOx emissions over North China during summer. Overall, it is estimated that the NOx emissions in North China are underestimated possibly by ~50% over an entire year. In order to confirm the uncertainty in NOx emissions, the NOx emission over South Korea was further investigated using the ACE-ASIA inventory, REAS (Regional Emission inventory in ASia) and CAPSS (Clean Air Policy Support System) by NIER (National Institute of Environmental Research) in Korea. The NOx emissions from ACE-ASIA and the REAS inventories appear to be approximately 2 times larger for mega-cities in Korea than that from the CAPSS inventory. In contrast, the NOx emissions of ACE-ASIA and REAS inventories are only 10% smaller for North China than the recently-estimated "date-back" ANL (Argonne National Laboratory) inventory. A comparison between the CMAQ-predicted and GOME-derived NO2 columns indicated that both the ACE-ASIA and REAS inventories have some uncertainty in NOx emissions over North China (A) and South Korea (C), which can lead to some error in modeling the formation of ozone and secondary aerosols in South Korea and North China.

scholarly journals Intercomparison of NO<sub><i>x</i></sub> emission inventories over East Asia

2017 ◽  
Vol 17 (16) ◽  
pp. 10125-10141 ◽  
Author(s):  
Jieying Ding ◽  
Kazuyuki Miyazaki ◽  
Ronald Johannes van der A ◽  
Bas Mijling ◽  
Jun-ichi Kurokawa ◽  
...  
Keyword(s):  
Kalman Filter ◽  
East Asia ◽  
Rural Areas ◽  
Emission Inventory ◽  
Regional Scale ◽  
Policy Support ◽  
Nox Emissions ◽  
Emission Inventories ◽  
Bottom Up ◽  
Temporal Behaviour

Abstract. We compare nine emission inventories of nitrogen oxides including four satellite-derived NOx inventories and the following bottom-up inventories for East Asia: REAS (Regional Emission inventory in ASia), MEIC (Multi-resolution Emission Inventory for China), CAPSS (Clean Air Policy Support System) and EDGAR (Emissions Database for Global Atmospheric Research). Two of the satellite-derived inventories are estimated by using the DECSO (Daily Emission derived Constrained by Satellite Observations) algorithm, which is based on an extended Kalman filter applied to observations from OMI or from GOME-2. The other two are derived with the EnKF algorithm, which is based on an ensemble Kalman filter applied to observations of multiple species using either the chemical transport model CHASER and MIROC-chem. The temporal behaviour and spatial distribution of the inventories are compared on a national and regional scale. A distinction is also made between urban and rural areas. The intercomparison of all inventories shows good agreement in total NOx emissions over mainland China, especially for trends, with an average bias of about 20 % for yearly emissions. All the inventories show the typical emission reduction of 10 % during the Chinese New Year and a peak in December. Satellite-derived approaches using OMI show a summer peak due to strong emissions from soil and biomass burning in this season. Biases in NOx emissions and uncertainties in temporal variability increase quickly when the spatial scale decreases. The analyses of the differences show the importance of using observations from multiple instruments and a high spatial resolution model for the satellite-derived inventories, while for bottom-up inventories, accurate emission factors and activity information are required. The advantage of the satellite-derived approach is that the emissions are soon available after observation, while the strength of the bottom-up inventories is that they include detailed information of emissions for each source category.

scholarly journals Fine-Scale Columnar and Surface NOx Concentrations over South Korea: Comparison of Surface Monitors, TROPOMI, CMAQ and CAPSS Inventory

Atmosphere ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 101 ◽  
Author(s):  
Hyun Cheol Kim ◽  
Soontae Kim ◽  
Sang-Hyun Lee ◽  
Byeong-Uk Kim ◽  
Pius Lee
Keyword(s):  
Air Quality ◽  
South Korea ◽  
Satellite Data ◽  
Emission Inventory ◽  
Point Sources ◽  
Policy Support ◽  
Spatial And Temporal Variation ◽  
Nox Emissions ◽  
Fine Scale ◽  
Surface Observations

Fine-scale nitrogen oxide (NOx) concentrations over South Korea are examined using surface observations, satellite data and high-resolution model simulations based on the latest emission inventory. While accurate information on NOx emissions in South Korea is crucial to understanding regional air quality in the region, consensus on the validation of NOx emissions is lacking. We investigate the spatial and temporal variation in fine-scale NOx emission sources over South Korea. Surface observations and newly available fine-scale satellite data (TROPOspheric Monitoring Instrument; TROPOMI; 3.5 × 7 km2) are compared with the community multiscale air quality (CMAQ) model based on the clean air policy support system (CAPSS) 2016 emission inventory. The results show that the TROPOMI NO2 column densities agree well with the CMAQ simulations based on CAPSS emissions (e.g., R = 0.96 for June 2018). The surface observations, satellite data and model are consistent in terms of their spatial distribution, the overestimation over the Seoul Metropolitan Area and major point sources; however, the model tends to underestimate the surface concentrations during the cold season.

scholarly journals Intercomparison of NO<sub><i>x</i></sub> emission inventories over East Asia

2017 ◽  
Author(s):  
Jieying Ding ◽  
Kazuyuki Miyazaki ◽  
Ronald Johannes van der A ◽  
Bas Mijling ◽  
Jun-ichi Kurokawa ◽  
...  
Keyword(s):  
Kalman Filter ◽  
East Asia ◽  
Rural Areas ◽  
Emission Inventory ◽  
Regional Scale ◽  
Policy Support ◽  
Nox Emissions ◽  
Emission Inventories ◽  
Bottom Up ◽  
Temporal Behaviour

Abstract. We compare 9 emission inventories of nitrogen oxides including four satellite-derived NOx inventories and the following bottom-up inventories for East Asia: REAS (Regional Emission inventory in ASia), MEIC (Multi-resolution Emission Inventory for China), CAPSS (Clean Air Policy Support System) and EDGAR (Emissions Database for Global Atmospheric Research). Two of the satellite-derived inventories are estimated by using the DECSO (Daily Emission derived Constrained by Satellite Observations) algorithm, which is based on an extended Kalman filter applied to observations from OMI or from GOME-2. The other two are derived with the EnKF algorithm, which is based on an ensemble Kalman Filter applied to observations of multiple species using either the chemical transport model CHASER and MIROC-chem. The temporal behaviour and spatial distribution of the inventories are compared on a national and regional scale. A distinction is also made between urban and rural areas. The intercomparison of all inventories shows good agreement in total NOx emissions over Mainland China, especially for trends, with an average bias of about 20 % for yearly emissions. All the inventories show the typical emission reduction of 10 % during the Chinese New Year and a peak in December. Satellite-derived approaches using OMI show a summer peak due to strong emissions from soil and biomass burning in this season. Biases in NOx emissions and uncertainties in temporal variability increase quickly when the spatial scale decreases. The analyses of the differences show: the importance of using observations from multiple instruments and a high spatial resolution model for the satellite-derived inventories, while for bottom-up inventories, accurate emission factors and activity information are required. The advantage of the satellite derived approach is that the emissions are soon available after observation, while the strength of the bottom-up inventories is that they include detailed information of emissions for each source category.

scholarly journals A comparison study between CMAQ-simulated and OMI-retrieved NO<sub>2</sub> columns over East Asia for evaluation of NO<sub>x</sub> emission fluxes of INTEX-B, CAPSS, and REAS inventories

2015 ◽  
Vol 15 (4) ◽  
pp. 1913-1938 ◽  
Author(s):  
K. M. Han ◽  
S. Lee ◽  
L. S. Chang ◽  
C. H. Song
Keyword(s):  
East Asia ◽  
Eastern China ◽  
Influential Factors ◽  
Nox Emission ◽  
Nox Emissions ◽  
Air Quality Model ◽  
Ozone Monitoring Instrument ◽  
Model Simulations ◽  
Tropospheric No2 ◽  
Emission Fluxes

Abstract. Comparison between the CMAQ (Community Multi-scale Air Quality Model)-calculated and OMI (Ozone Monitoring Instrument)-retrieved tropospheric NO2 columns was carried out for 2006 over East Asia (100–150° E; 20–50° N) to evaluate the bottom-up NOx emission fluxes of INTEX-B, CAPSS, and REAS v1.11 inventories. The three emission inventories were applied to the CMAQ model simulations for the countries of China, South Korea, and Japan, respectively. For the direct comparison between the two NO2 columns, the averaging kernels (AKs) obtained from the Royal Netherlands Meteorological Institute (KNMI)/DOMINO v2.0 daily product were applied to the CMAQ-simulated data. The analysis showed that the two tropospheric NO2 columns from the CMAQ model simulations and OMI observations (ΩCMAQ,AK and ΩOMI) had good spatial and seasonal correlation, with correlation coefficients ranging from 0.71 to 0.96. In addition, the normalized mean errors (NMEs) between the ΩCMAQ,AK and ΩOMI were found to range from ~ 40 to ~ 63%. The ΩCMAQ,AK were, on annual average, ~ 28% smaller (in terms of the NMEs) than the ΩOMI, indicating that the NOx emissions used were possibly underestimated in East Asia. Large absolute differences between the ΩCMAQ,AK and ΩOMI were found, particularly over central eastern China (CEC) during winter (annual averaged mean error of ~ 4.51 × 1015 molecules cm−2). Although such differences between the ΩCMAQ,AK and ΩOMI are likely caused by the errors and biases in the NOx emissions used in the CMAQ model simulations, it can be rather difficult to quantitatively relate the differences to the accuracy of the NOx emissions, because there are also several uncertain factors in the CMAQ model, satellite-retrieved NO2 columns and AK products, and NOx and other trace gas emissions. In this context, three uncertain factors were selected and analyzed with sensitivity runs (monthly variations in NOx emissions; influences of different NOx emission fluxes; and reaction probability of N2O5 radicals). Other uncertain or possible influential factors were also discussed to suggest future direction of the study.

scholarly journals An Estimation of Top-Down NOx Emissions from OMI Sensor Over East Asia

2020 ◽  
Vol 12 (12) ◽  
pp. 2004 ◽  
Author(s):  
Kyung M. Han ◽  
Hyun S. Kim ◽  
Chul H. Song
Keyword(s):  
East Asia ◽  
Mass Conservation ◽  
Weather Research And Forecasting ◽  
Nox Emissions ◽  
Wind Vector ◽  
Ozone Monitoring Instrument ◽  
Top Down ◽  
Model Simulations ◽  
Ozone Monitoring ◽  
Atmospheric Factors

This study focuses on the estimation of top-down NOx emissions over East Asia, integrating information on the levels of NO2 and NO, wind vector, and geolocation from Ozone Monitoring Instrument (OMI) observations and Weather Research and Forecasting (WRF)-Community Multiscale Air Quality (CMAQ) model simulations. An algorithm was developed based on mass conservation to estimate the 30 km × 30 km resolved top-down NOx emissions over East Asia. In particular, the algorithm developed in this study considered two main atmospheric factors—(i) NOx transport from/to adjacent cells and (ii) calculations of the lifetimes of column NOx (τ). In the sensitivity test, the analysis showed the improvements in the top-down NOx estimation via filtering the data (τ ≤ 2 h). The best top-down NOx emissions were inferred after the sixth iterations. Those emissions were 11.76 Tg N yr−1 over China, 0.13 Tg N yr−1 over North Korea, 0.46 Tg N yr−1 over South Korea, and 0.68 Tg N yr−1 over Japan. These values are 34%, 62%, 60%, and 47% larger than the current bottom-up NOx emissions over these countries, respectively. A comparison between the CMAQ-estimated and OMI-retrieved NO2 columns was made to confirm the accuracy of the newly estimated NOx emission. The comparison confirmed that the estimated top-down NOx emissions showed better agreements with observations (R2 = 0.88 for January and 0.81 for July).

Diagnosing and Debunking Korean Pseudohistory

2019 ◽  
pp. 37-80
Author(s):  
Andrew Logie
Keyword(s):  
South Korea ◽  
East Asia ◽  
20Th Century ◽  
Inner Mongolia ◽  
Political Influence ◽  
The Core ◽  
Early State

In current day South Korea pseudohistory pertaining to early Korea and northern East Asia has reached epidemic proportions. Its advocates argue the early state of Chosŏn to have been an expansive empire centered on mainland geographical Manchuria. Through rationalizing interpretations of the traditional Hwan’ung- Tan’gun myth, they project back the supposed antiquity and pristine nature of this charter empire to the archaeological Hongshan Culture of the Neolithic straddling Inner Mongolia and Liaoning provinces of China. Despite these blatant spatial and temporal exaggerations, all but specialists of early Korea typically remain hesitant to explicitly label this conceptualization as “pseudohistory.” This is because advocates of ancient empire cast themselves as rationalist scholars and claim to have evidential arguments drawn from multiple textual sources and archaeology. They further wield an emotive polemic defaming the domestic academic establishment as being composed of national traitors bent only on maintaining a “colonial view of history.” The canon of counterevidence relied on by empire advocates is the accumulated product of 20th century revisionist and pseudo historiography, but to willing believers and non-experts, it can easily appear convincing and overwhelming. Combined with a postcolonial nationalist framing and situated against the ongoing historiography dispute with China, their conceptualization of a grand antiquity has gained bipartisan political influence with concrete ramifications for professional scholarship. This paper seeks to introduce and debunk the core, seemingly evidential, canon of arguments put forward by purveyors of Korean pseudohistory and to expose their polemics, situating the phenomenon in a broader diagnostic context of global pseudohistory and archaeology.

Tersilochinae of South, Southeast and East Asia, excluding Mongolia and Japan (Hymenoptera: Ichneumonidae)

2011 ◽  
Vol 20 (1) ◽  
pp. 96-148 ◽  
Author(s):  
A.I. Khalaim
Keyword(s):  
Sri Lanka ◽  
South Korea ◽  
East Asia ◽  
Far East ◽  
New Combination ◽  
East China ◽  
Far East Of Russia ◽  
Undescribed Species ◽  
Oriental Region ◽  
Unidentified Species

Tersilochines of South, Southeast and East Asia (excluding Mongolia and Japan) have been studied. Eight genera and 60 species are recorded in the region: Allophrys (2 species), Barycnemis (5 species), Diaparsis (29 species), Phradis (2 species, including 1 unidentified species), Probles (12 species, including 1 unidentified and 6 undescribed species), Sathropterus (2 species), Slonopotamus gen. nov. (2 species) and Tersilochus (6 species, including one species of the obscure status). One genus and 26 species are described as new: Allophrys bruneiensis sp. nov. (Brunei), A. occipitata sp. nov. (Vietnam, India), Diaparsis absista sp. nov. (Brunei), D. bannapeana sp. nov. (Laos), D. bolikhamsaica sp. nov. (Laos, Thailand), D. brunnea sp. nov. (Brunei), D. crenulator sp. nov. (Brunei), D. dediticia sp. nov. (Vietnam, Brunei), D. hilaris sp. nov. (Vietnam), D. karnatakana sp. nov. (India), D. labiensis sp. nov. (Brunei), D. mandibulator sp. nov. (Laos), D. minuta sp. nov. (Vietnam), D. monstrosa sp. nov. (Brunei), D. morleyi sp. nov. (Sri Lanka), D. propodeator sp. nov. (Brunei, Sarawak State of Malaysia, southern Indonesia, Laos), D. pulchra sp. nov. (South Korea), D. sarawakiensis sp. nov. (Sarawak and Pahang states of Malaysia), D. viela sp. nov. (Vietnam, Laos), D. vietnamica sp. nov. (Vietnam), D. zispina sp. nov. (Vietnam), Probles vietnamica sp. nov. (Vietnam, probably East China and south of Far East of Russia), Sathropterus secundus sp. nov. (Vietnam), Slonopotamus elephantoides sp. nov. (Laos), S. indianus sp. nov. (India) and Tersilochus granulatus sp. nov. (South Korea). Generic assignment of two species are changed: Barycnemis sanctijohanni (Rao & Kurian, 1951), new combination, and Probles (Microdiaparsis) caudate (Morley, 1913), new combination. Barycnemis dissimilis and B. tobiasi from Nepal, Diaparsis convexa from Vietnam, D. niphadoctona from Laos, and Sathropterus pumilus from India and Nepal are newly recorded from the countries. The genus Diaparsis comprises almost half of species of the tersilochine fauna of the studied region (29 species, 48%), and is a dominant genus in the Oriental Region. Keys to genera and species of Tersilochinae of South, Southeast and East Asia (excluding Mongolia and Japan) are provided.

scholarly journals Regional variability in black carbon and carbon monoxide ratio from long-term observations over East Asia: assessment of representativeness for black carbon (BC) and carbon monoxide (CO) emission inventories

2020 ◽  
Vol 20 (1) ◽  
pp. 83-98 ◽  
Author(s):  
Yongjoo Choi ◽  
Yugo Kanaya ◽  
Seung-Myung Park ◽  
Atsushi Matsuki ◽  
Yasuhiro Sadanaga ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
South Korea ◽  
East Asia ◽  
Black Carbon ◽  
North Korea ◽  
Northeast China ◽  
Emission Inventory ◽  
East China ◽  
Co Emission

Abstract. The black carbon (BC) and carbon monoxide (CO) emission ratios were estimated and compiled from long-term, harmonized observations of the ΔBC∕ΔCO ratios under conditions unaffected by wet deposition at four sites in East Asia, including two sites in South Korea (Baengnyeong and Gosan) and two sites in Japan (Noto and Fukuoka). Extended spatio-temporal coverage enabled estimation of the full seasonality and elucidation of the emission ratio in North Korea for the first time. The estimated ratios were used to validate the Regional Emission inventory in ASia (REAS) version 2.1 based on six study domains (“East China”, “North China”, “Northeast China”, South Korea, North Korea, and Japan). We found that the ΔBC∕ΔCO ratios from four sites converged into a narrow range (6.2–7.9 ng m−3 ppb−1), suggesting consistency in the results from independent observations and similarity in source profiles over the regions. The BC∕CO ratios from the REAS emission inventory (7.7 ng m−3 ppb−1 for East China – 23.2 ng m−3 ppb−1 for South Korea) were overestimated by factors of 1.1 for East China to 3.0 for South Korea, whereas the ratio for North Korea (3.7 ng m−3 ppb−1 from REAS) was underestimated by a factor of 2.0, most likely due to inaccurate emissions from the road transportation sector. Seasonal variation in the BC∕CO ratio from REAS was found to be the highest in winter (China and North Korea) or summer (South Korea and Japan), whereas the measured ΔBC∕ΔCO ratio was the highest in spring in all source regions, indicating the need for further characterization of the seasonality when creating a bottom-up emission inventory. At levels of administrative districts, overestimation in Seoul, the southwestern regions of South Korea, and Northeast China was noticeable, and underestimation was mainly observed in the western regions in North Korea, including Pyongyang. These diagnoses are useful for identifying regions where revisions in the inventory are necessary, providing guidance for the refinement of BC and CO emission rate estimates over East Asia.

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