Updated tropospheric chemistry reanalysis and emission estimates, TCR-2, for 2005–2018

Miyazaki, Kazuyuki; Bowman, K. W.; Sekiya, Takashi; Eskes, Henk; Boersma, K. Folkert; Worden, H. M.; Livesey, N. J.; Payne, Vivienne H.; Sudo, Kengo; Kanaya, Yugo; Takigawa, Masayuki; Ogochi, Koji

doi:10.5194/essd-12-2223-2020

Cited by 83 publications

(107 citation statements)

References 106 publications

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“…Chinese emissions are typically low from January to February as a consequence of CNY. Climatological variations referenced to CNY in Figure 1 are derived from our 16‐year (2005–2020) emission time series (Miyazaki, Bowman, Sekiya, et al, 2020). These reductions start about 20 days beforehand and reach their nadir after CNY before recovering about a month later.…”

Section: Resultsmentioning

confidence: 99%

“…An extended calculation of the Tropospheric Chemistry Reanalysis Version 2 (TCR‐2) (Miyazaki, Bowman, Sekiya, et al, 2020) is used to evaluate emission and concentration changes (Texts S1 and S2 in the supporting information). The data products used in this study have been obtained from the assimilation of multiple satellite measurements of ozone, CO, NO 2 , HNO 3 , and SO 2 from the OMI, TROPOMI, MLS, and MOPITT satellite instruments (Text S3).…”

Section: Methodsmentioning

confidence: 99%

“…Consequently, health impacts, which we compute based upon population and exposure‐response relationships (Liang et al, 2018), account for the effect of both local and nonlocal emissions changes. For these estimates, we use a multiconstituent satellite data assimilation system (Miyazaki, Bowman, Sekiya, et al, 2020), which simultaneously optimizes concentrations and emissions of various species while taking their complex chemical interactions into account.…”

Section: Introductionmentioning

confidence: 99%

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Air Quality Response in China Linked to the 2019 Novel Coronavirus (COVID‐19) Lockdown

Miyazaki

Bowman

Sekiya

et al. 2020

Geophysical Research Letters

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Efforts to stem the spread of COVID-19 in China hinged on severe restrictions to human movement starting 23 January 2020 in Wuhan and subsequently to other provinces. Here, we quantify the ancillary impacts on air pollution and human health using inverse emissions estimates based on multiple satellite observations. We find that Chinese NOx emissions were reduced by 36% from early January to mid-February, with more than 80% of reductions occurring after their respective lockdown in most provinces. The reduced precursor emissions increased surface ozone by up to 16 ppb over northern China but decreased PM2.5 by up to 23 μg m −3 nationwide. Changes in human exposure are associated with about 2,100 more ozone-related and at least 60,000 fewer PM2.5-related morbidity incidences, primarily from asthma cases, thereby augmenting efforts to reduce hospital admissions and alleviate negative impacts from potential delayed treatments. Plain Language Summary Satellite measurements such as TROPOMI have already captured the public's attention through remarkable images of pollutant reductions. However, the inference of emissions must account for variations in atmospheric transport, chemical environment, and meteorology. To that end, we used an advanced chemical data assimilation system that incorporate these factors through ingestion of multiple chemical satellite and in situ observations into a chemical transport model. We then quantified the reductions in emissions attributable to COVID-19 lockdown and determine the impact of those reduction on human health through pollutant exposure. We find that our Chinese NOx emission reductions had opposing air quality responses depending on timing, location, and pollutant. Our investigation showed increases in ozone-related morbidity incidences in Northern China but larger nationwide reductions from PM2.5 that led to overall reductions in hospital admissions and alleviating negative impacts of delayed treatment.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Air Quality Response in China Linked to the 2019 Novel Coronavirus (COVID‐19) Lockdown

Miyazaki

Bowman

Sekiya

et al. 2020

Geophysical Research Letters

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“…All the larger alkanes (i-butane, n-butane, i-pentane, n-pentane, nhexane, n-heptane, n-octane, n-nonane, n-decane), alkenes (1-butene, i-butene, trans-3-butene and 1-3-butadiene), and xylenes (m-,p-xylene, o-xylene) were summed (Table 3) for comparison with the BIGALK, BIGENE, and xylenes, respectively, of the T1 surrogate species . Methanol (CH 3 OH), acetaldehyde (CH 3 CHO), acetone (CH 3 COCH 3 ), benzene (C 6 H 6 ), and toluene (C 7 H 8 ) were measured with the proton-transfer-reaction time-offlight mass spectrometer (PTR-ToF-MS) at 10 Hz frequency (Müller et al, 2014). We also evaluate some meteorological parameters (Chan et al, 1998), such as temperature, wind speed, and water vapor moist volumetric mixing ratio measured by the NASA open-path diode laser hygrometer (Diskin et al, 2002;Podolske et al, 2003), with a 5 % uncertainty.…”

Section: Discussionmentioning

confidence: 99%

Correcting model biases of CO in East Asia: impact on oxidant distributions during KORUS-AQ

et al. 2020

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Abstract. Global coupled chemistry–climate models underestimate carbon monoxide (CO) in the Northern Hemisphere, exhibiting a pervasive negative bias against measurements peaking in late winter and early spring. While this bias has been commonly attributed to underestimation of direct anthropogenic and biomass burning emissions, chemical production and loss via OH reaction from emissions of anthropogenic and biogenic volatile organic compounds (VOCs) play an important role. Here we investigate the reasons for this underestimation using aircraft measurements taken in May and June 2016 from the Korea–United States Air Quality (KORUS-AQ) experiment in South Korea and the Air Chemistry Research in Asia (ARIAs) in the North China Plain (NCP). For reference, multispectral CO retrievals (V8J) from the Measurements of Pollution in the Troposphere (MOPITT) are jointly assimilated with meteorological observations using an ensemble adjustment Kalman filter (EAKF) within the global Community Atmosphere Model with Chemistry (CAM-Chem) and the Data Assimilation Research Testbed (DART). With regard to KORUS-AQ data, CO is underestimated by 42 % in the control run and by 12 % with the MOPITT assimilation run. The inversion suggests an underestimation of anthropogenic CO sources in many regions, by up to 80 % for northern China, with large increments over the Liaoning Province and the North China Plain (NCP). Yet, an often-overlooked aspect of these inversions is that correcting the underestimation in anthropogenic CO emissions also improves the comparison with observational O3 datasets and observationally constrained box model simulations of OH and HO2. Running a CAM-Chem simulation with the updated emissions of anthropogenic CO reduces the bias by 29 % for CO, 18 % for ozone, 11 % for HO2, and 27 % for OH. Longer-lived anthropogenic VOCs whose model errors are correlated with CO are also improved, while short-lived VOCs, including formaldehyde, are difficult to constrain solely by assimilating satellite retrievals of CO. During an anticyclonic episode, better simulation of O3, with an average underestimation of 5.5 ppbv, and a reduction in the bias of surface formaldehyde and oxygenated VOCs can be achieved by separately increasing by a factor of 2 the modeled biogenic emissions for the plant functional types found in Korea. Results also suggest that controlling VOC and CO emissions, in addition to widespread NOx controls, can improve ozone pollution over East Asia.

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“…S3). Having estimated the emission changes using the preceding bottom-up method, in order to prove the reliability of our bottom-up emissions, we compare the changes in nitrogen oxide (NO x ) emissions with a top-down satellite-based emission inventory -an extended calculation of the Tropospheric Chemistry Reanalysis version 2 (TCR-2) (Miyazaki et al, 2020a 2) reduction estimated based on the bottom-up method. That said, we acknowledge that, since more detailed data to support a more accurate estimation are not yet available, the estimates of the sector-specific relative changes in emissions inevitably involve some degree of uncertainty, which can be improved in future work.…”

Section: Model Configuration and Emission Estimationmentioning

confidence: 99%

Modeling the impact of COVID-19 on air quality in southern California: implications for future control policies

et al. 2021

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Abstract. In response to the coronavirus disease of 2019 (COVID-19), California issued statewide stay-at-home orders, bringing about abrupt and dramatic reductions in air pollutant emissions. This crisis offers us an unprecedented opportunity to evaluate the effectiveness of emission reductions in terms of air quality. Here we use the Weather Research and Forecasting model with Chemistry (WRF-Chem) in combination with surface observations to study the impact of the COVID-19 lockdown measures on air quality in southern California. Based on activity level statistics and satellite observations, we estimate the sectoral emission changes during the lockdown. Due to the reduced emissions, the population-weighted concentrations of fine particulate matter (PM2.5) decrease by 15 % in southern California. The emission reductions contribute 68 % of the PM2.5 concentration decrease before and after the lockdown, while meteorology variations contribute the remaining 32 %. Among all chemical compositions, the PM2.5 concentration decrease due to emission reductions is dominated by nitrate and primary components. For O3 concentrations, the emission reductions cause a decrease in rural areas but an increase in urban areas; the increase can be offset by a 70 % emission reduction in anthropogenic volatile organic compounds (VOCs). These findings suggest that a strengthened control on primary PM2.5 emissions and a well-balanced control on nitrogen oxides and VOC emissions are needed to effectively and sustainably alleviate PM2.5 and O3 pollution in southern California.

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Updated tropospheric chemistry reanalysis and emission estimates, TCR-2, for 2005–2018

Cited by 83 publications

References 106 publications

Air Quality Response in China Linked to the 2019 Novel Coronavirus (COVID‐19) Lockdown

Air Quality Response in China Linked to the 2019 Novel Coronavirus (COVID‐19) Lockdown

Correcting model biases of CO in East Asia: impact on oxidant distributions during KORUS-AQ

Modeling the impact of COVID-19 on air quality in southern California: implications for future control policies

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