Continental-scale contributions to the global CFC-11 emission increase between 2012 and 2017

Abstract. The early detection of a global emission increase of CFC-11 after 2012 (Montzka et al., 2018) alerted society to a possible violation of the Montreal Protocol on Substances that Deplete the Ozone Layer (MP). This early alert resulted in parties participating in the MP taking urgent actions (United Nations Environment Programme (UNEP), 2019). As a result, atmospheric measurements made in 2019 suggest a sharp decline in global CFC-11 emissions (Montzka et al., 2021). Despite the success in the early detection and mitigation of some of this problem, regions fully responsible for the recent global emission changes of CFC-11 have not yet been identified. Roughly two thirds (60 ± 40 %) of the emission increase between 2008–2012 and 2014–2017 and two thirds (60 ± 30 %) of emission decline between 2014–2017 and 2019 was explained by regional emission changes in eastern mainland China (Park et al., 2021; Rigby et al., 2019). Here, we used atmospheric CFC-11 measurements made from two global aircraft surveys, the HIAPER Pole-to-Pole Observations (HIPPO) in November 2009–September 2011 and the Atmospheric Tomography Mission (ATom) in August 2016–May 2018, in combination with the global CFC-11 measurements made by the U.S. National Oceanic and Atmospheric Administration during these two periods, to derive global and regional emission changes of CFC-11. Our results suggest Asia accounted for the largest fractions of global CFC-11 emissions in both periods, 43 (37–52) % during November 2009–September 2011 and 57 (49–62) % during August 2016–May 2018. Asia was also primarily responsible for the emission increase between these two periods, accounting for 86 (59–115) % of the global CFC-11 emission rise between the two periods. Besides eastern mainland China, we find that temperate western Asia and tropical Asia also contributed significantly to global CFC-11 emissions during both periods and likely to the global CFC-11 emission increase between these periods. Besides Asia, the atmospheric observations also provide strong constraints on CFC-11 emissions from North America and Europe, suggesting that each of them accounted for 10–15 % of global CFC-11 emissions during the HIPPO period and smaller fractions in the ATom period. For South America, Africa, and Australia, the derived regional emissions had larger dependence on the prior assumptions of emissions and emission changes, due to a lower sensitivity of the observations considered here to emissions from these regions. However, significant increases in CFC-11 emissions from the southern hemispheric lands were not likely due to the observed increase of north-to-south interhemispheric gradients in atmospheric CFC-11 mole fractions from 2012 to 2017.

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Emissions of halocarbons from India inferred through atmospheric measurements

Atmospheric Chemistry and Physics ◽

10.5194/acp-19-9865-2019 ◽

2019 ◽

Vol 19 (15) ◽

pp. 9865-9885 ◽

Cited By ~ 5

Author(s):

Daniel Say ◽

Anita L. Ganesan ◽

Mark F. Lunt ◽

Matthew Rigby ◽

Simon O'Doherty ◽

...

Keyword(s):

Rapid Growth ◽

Central India ◽

Fold Increase ◽

Montreal Protocol ◽

Emission Rates ◽

Atmospheric Measurements ◽

Modelling Framework ◽

Global Emission ◽

Atmospheric Measurement ◽

Ozone Depleting Substances

Abstract. As the second most populous country and third fastest growing economy, India has emerged as a global economic power. As such, its emissions of greenhouse and ozone-depleting gases are of global significance. However, unlike neighbouring China, the Indian sub-continent is very poorly monitored by atmospheric measurement networks. India's halocarbon emissions, here defined as chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs) and chlorocarbons, are not well-known. Previous measurements from the region have been obtained at observatories many hundreds of kilometres from source regions, or at high altitudes, limiting their value for the estimation of regional emission rates. Given the projected rapid growth in demand for refrigerants and solvents in India, emission estimates of these halocarbons are urgently needed to provide a benchmark against which future changes can be evaluated. In this study, we report atmospheric-measurement-derived halocarbon emissions from India. With the exception of dichloromethane, these top-down estimates are the first for India's halocarbons. Air samples were collected at low altitude during an aircraft campaign in June and July 2016, and emissions were derived from measurements of these samples using an inverse modelling framework. These results were evaluated to assess India's progress in phasing out ozone-depleting substances under the Montreal Protocol. India's combined CFC emissions are estimated to be 54 (27–86) Tg CO2 eq. yr−1 (5th and 95th confidence intervals are shown in parentheses). HCFC-22 emissions of 7.8 (6.0–9.9) Gg yr−1 are of similar magnitude to emissions of HFC-134a (8.2 (6.1–10.7) Gg yr−1). We estimate India's HFC-23 emissions to be 1.2 (0.9–1.5) Gg yr−1, and our results are consistent with resumed venting of HFC-23 by HCFC-22 manufacturers following the discontinuation of funding for abatement under the Clean Development Mechanism. We report small emissions of HFC-32 and HFC-143a and provide evidence to suggest that HFC-32 emissions were primarily due to fugitive emissions during manufacturing processes. A lack of significant correlation among HFC species and the small emissions derived for HFC-32 and HFC-143a indicate that in 2016, India's use of refrigerant blends R-410A, R-404A and R-507A was limited, despite extensive consumption elsewhere in the world. We also estimate emissions of the regulated chlorocarbons carbon tetrachloride and methyl chloroform from northern and central India to be 2.3 (1.5–3.4) and 0.07 (0.04–0.10) Gg yr−1 respectively. While the Montreal Protocol has been successful in reducing emissions of many ozone-depleting substances, growth in the global emission rates of the unregulated very short-lived substances poses an ongoing threat to the recovery of the ozone layer. Emissions of dichloromethane are found to be 96.5 (77.8–115.6) Gg yr−1, and our estimate suggests a 5-fold increase in emissions since the last estimate derived from atmospheric data in 2008. We estimate perchloroethene emissions from India and chloroform emissions from northern–central India to be 2.9 (2.5–3.3) and 32.2 (28.3–37.1) Gg yr−1 respectively. Given the rapid growth of India's economy and the likely increase in demand for halocarbons such as HFCs, the implementation of long-term atmospheric monitoring in the region is urgently required. Our results provide a benchmark against which future changes to India's halocarbon emissions may be evaluated.

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Atmospheric observations and emission estimates of ozone-depleting chlorocarbons from India

10.5194/acp-2018-1287 ◽

2019 ◽

Cited By ~ 1

Author(s):

Daniel Say ◽

Anita L. Ganesan ◽

Mark F. Lunt ◽

Matthew Rigby ◽

Simon O'Doherty ◽

...

Keyword(s):

Central India ◽

Fold Increase ◽

Montreal Protocol ◽

Emission Rates ◽

Atmospheric Measurements ◽

Potential Threat ◽

Global Emission ◽

Methyl Chloroform ◽

Growing Economy ◽

Ozone Depleting Substances

Abstract. While the Montreal Protocol has been successful in reducing emissions of many long-lived ozone-depleting substances, growth in the global emission rates of unregulated very short-lived substances (VSLS) poses a potential threat to the recovery of the ozone layer. The sources of these VSLS are not well-constrained, with major source regions poorly monitored by existing measurement networks. Given India's rapidly growing economy, its emissions of both regulated chlorocarbons and unregulated VSLS chlorocarbons are suspected to have global significance. Furthermore, VSLS from the Asian monsoon regions have a greater impact on ozone-depletion than those emitted elsewhere due to the ability of monsoon systems to rapidly transport pollutants to the lower stratosphere. Previous atmospheric measurements of chlorocarbons from the Indian sub-continent are scarce. Here we present a new set of observations, derived from flask samples collected during a 2-month aircraft campaign in India and use these measurements to infer India's chlorocarbon emissions. We show that emissions of carbon tetrachloride from northern and central India (2.3 (1.5–3.4) Gg yr−1), are likely due to inadvertent production and release during the manufacture of chloromethanes (specifically dichloromethane and chloroform) and account for approximately 7 % of the global total. Emissions of methyl chloroform from the same region were estimated to be 0.07 (0.04–0.10) Gg yr−1 which account for less than 5 % of remaining global emissions. We used a population scaling to estimate India's emissions of the very short-lived chlorocarbons dichloromethane, perchloroethene and chloroform, which were estimated to be 69.2 (55.8–82.9) Gg yr−1, 2.9 (2.5–3.3) Gg yr−1 and 25.7 (21.6–29.9) Gg yr−1 respectively. In the case of dichloromethane, our estimate is consistent with a 3-fold increase in emissions since the last estimate derived from atmospheric data in 2008.

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Circulating Cell-Free Tumour DNA for Early Detection of Pancreatic Cancer

Cancers ◽

10.3390/cancers12123704 ◽

2020 ◽

Vol 12 (12) ◽

pp. 3704

Author(s):

Jedrzej J. Jaworski ◽

Robert D. Morgan ◽

Shivan Sivakumar

Keyword(s):

Pancreatic Cancer ◽

Early Detection ◽

Early Stage ◽

Lower Sensitivity ◽

Detection Rates ◽

Early Stage Disease ◽

Genetic Sequencing ◽

Number Of Factors ◽

Stage Disease ◽

Invasive Method

Pancreatic cancer is a lethal disease, with mortality rates negatively associated with the stage at which the disease is detected. Early detection is therefore critical to improving survival outcomes. A recent focus of research for early detection is the use of circulating cell-free tumour DNA (ctDNA). The detection of ctDNA offers potential as a relatively non-invasive method of diagnosing pancreatic cancer by using genetic sequencing technology to detect tumour-specific mutational signatures in blood samples before symptoms manifest. These technologies are limited by a number of factors that lower sensitivity and specificity, including low levels of detectable ctDNA in early stage disease and contamination with non-cancer circulating cell-free DNA. However, genetic and epigenetic analysis of ctDNA in combination with other standard diagnostic tests may improve early detection rates. In this review, we evaluate the genetic and epigenetic methods under investigation in diagnosing pancreatic cancer and provide a perspective for future developments.

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Global emissions of VOCs from compressed aerosol products

Elem Sci Anth ◽

10.1525/elementa.2020.20.00177 ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Amber M. Yeoman ◽

Alastair C. Lewis

Keyword(s):

Economic Status ◽

Montreal Protocol ◽

Passenger Cars ◽

Middle Income ◽

Voc Emissions ◽

Product Formulation ◽

Global Emission ◽

Order Of Magnitude ◽

The Uk ◽

Global Emissions

Disposable compressed gas aerosols have been a ubiquitous part of life since the mid-1950s. The signing of the Montreal Protocol in 1987 led to aerosol propellants changing from halocarbons to less damaging replacements; around 93% of current aerosol emissions by mass are volatile organic compounds (VOCs), with small contributions from compressed air (6.6%) and fluorocarbons (0.4%). The global consumption of aerosol units has increased significantly since the signing of the Montreal Protocol, increasing by an order of magnitude in some countries. In high-income countries, annual consumption increased through the 1990s and 2000s, typically reaching a plateau of approximately 10 ± 3 units person–1 year–1 dependant on product preferences. The largest contributors of both units and mass emissions are personal care products (PCPs). Consumption of aerosols in lower- and upper-middle income countries are growing rapidly, for example, Brazil, Mexico, China, Thailand, all tripling reported consumption since 2006. Based on evidence drawn from national production estimates, product specifications and formulations, and interpolation of usage between countries of similar economic status, we estimate global emissions of VOC from aerosol propellants were approximately 1.3 ± 0.23 Tg year–1 in 2018. The fraction of anthropogenic VOC emissions accounted for by aerosols has in some countries increased significantly as emissions from vehicles and fuels have declined. For example, in the UK, 6.1% of anthropogenic VOC emissions were from aerosols in 2017, more than were released from gasoline passenger cars. Should low- and middle-income economies grow consumption per capita in line with recent trends, then we project global aerosol consumption may reach approximately 4.4 ± 0.96 × 1010 units year–1 in 2050. Should existing national and international policies on aerosol product formulation remain unchanged, and VOCs remain the dominant propellant, compressed aerosols could account for a global emission of approximately 2.2 ± 0.48 Tg year–1 in 2050.

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Lower air pollution during COVID-19 lock-down: improving models and methods estimating ozone impacts on crops

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2020.0188 ◽

2020 ◽

Vol 378 (2183) ◽

pp. 20200188 ◽

Cited By ~ 3

Author(s):

Frank Dentener ◽

Lisa Emberson ◽

Stefano Galmarini ◽

Giovanni Cappelli ◽

Anisoara Irimescu ◽

...

Keyword(s):

Crop Yields ◽

Growing Season ◽

Road Transport ◽

Initial Assessment ◽

Emission Reductions ◽

International Shipping ◽

Crop Models ◽

Global Emission ◽

Emission Changes ◽

Ozone Precursor

We suggest that the unprecedented and unintended decrease of emissions of air pollutants during the COVID-19 lock-down in 2020 could lead to declining seasonal ozone concentrations and positive impacts on crop yields. An initial assessment of the potential effects of COVID-19 emission reductions was made using a set of six scenarios that variously assumed annual European and global emission reductions of 30% and 50% for the energy, industry, road transport and international shipping sectors, and 80% for the aviation sector. The greatest ozone reductions during the growing season reached up to 12 ppb over crop growing regions in Asia and up to 6 ppb in North America and Europe for the 50% global reduction scenario. In Europe, ozone responses are more sensitive to emission declines in other continents, international shipping and aviation than to emissions changes within Europe. We demonstrate that for wheat the overall magnitude of ozone precursor emission changes could lead to yield improvements between 2% and 8%. The expected magnitude of ozone precursor emission reductions during the Northern Hemisphere growing season in 2020 presents an opportunity to test and improve crop models and experimentally based exposure response relationships of ozone impacts on crops, under real-world conditions. This article is part of a discussion meeting issue ‘Air quality, past present and future’.

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The Efficacy of General Practitioner Assessment of Cognition in Chinese Elders Aged 80 and Older

American Journal of Alzheimer s Disease & Other Dementias® ◽

10.1177/1533317519860333 ◽

2019 ◽

Vol 34 (7-8) ◽

pp. 523-529

Author(s):

Fang Xu ◽

Juan Juan Ma ◽

Fei Sun ◽

Jaewon Lee ◽

David W. Coon ◽

...

Keyword(s):

General Practitioner ◽

Mini Mental State Examination ◽

Mainland China ◽

University Hospital ◽

Comparable Efficacy ◽

Lower Sensitivity ◽

Clinical Settings ◽

Older Chinese ◽

State Examination ◽

Survey Questionnaires

Objectives: This study examined the efficacy of the General Practitioner Assessment of Cognition–Chinese version (GPCOG-C) in screening dementia and mild cognitive impairment (MCI) among older Chinese. Methods: Survey questionnaires were administered to 293 participants aged 80 or above from a university hospital in mainland China. Alzheimer disease and MCI were diagnosed in light of the National Institute on Aging and the Alzheimer’s Association (NIA/AA) criteria. The sensitivity and specificity of GPCOG-C and Mini-Mental State Examination (MMSE) in screening dementia and MCI were compared to the NIA/AA criteria. Results: The GPCOG-C had the sensitivity of 62.3% and specificity of 84.6% in screening MCI, which had comparable efficacy as the NIA/AA criteria. In screening dementia, GPCOG-C had a lower sensitivity (63.7%) than the MMSE and a higher specificity (82.6%) higher than the MMSE. Conclusions: The GPCOG-C is a useful and efficient tool to identify dementia and MCI in older Chinese in outpatient clinical settings.

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Stratospheric ozone depletion

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2005.1783 ◽

2006 ◽

Vol 361 (1469) ◽

pp. 769-790 ◽

Cited By ~ 98

Author(s):

F. Sherwood Rowland

Keyword(s):

Ultraviolet Radiation ◽

Ozone Depletion ◽

Biological Activities ◽

Stratospheric Ozone ◽

Ozone Layer ◽

Ultraviolet B ◽

Montreal Protocol ◽

Atmospheric Measurements ◽

Solar Ultraviolet Radiation ◽

Solar Ultraviolet

Solar ultraviolet radiation creates an ozone layer in the atmosphere which in turn completely absorbs the most energetic fraction of this radiation. This process both warms the air, creating the stratosphere between 15 and 50 km altitude, and protects the biological activities at the Earth's surface from this damaging radiation. In the last half-century, the chemical mechanisms operating within the ozone layer have been shown to include very efficient catalytic chain reactions involving the chemical species HO, HO 2 , NO, NO 2 , Cl and ClO. The NO X and ClO X chains involve the emission at Earth's surface of stable molecules in very low concentration (N 2 O, CCl 2 F 2 , CCl 3 F, etc.) which wander in the atmosphere for as long as a century before absorbing ultraviolet radiation and decomposing to create NO and Cl in the middle of the stratospheric ozone layer. The growing emissions of synthetic chlorofluorocarbon molecules cause a significant diminution in the ozone content of the stratosphere, with the result that more solar ultraviolet-B radiation (290–320 nm wavelength) reaches the surface. This ozone loss occurs in the temperate zone latitudes in all seasons, and especially drastically since the early 1980s in the south polar springtime—the ‘Antarctic ozone hole’. The chemical reactions causing this ozone depletion are primarily based on atomic Cl and ClO, the product of its reaction with ozone. The further manufacture of chlorofluorocarbons has been banned by the 1992 revisions of the 1987 Montreal Protocol of the United Nations. Atmospheric measurements have confirmed that the Protocol has been very successful in reducing further emissions of these molecules. Recovery of the stratosphere to the ozone conditions of the 1950s will occur slowly over the rest of the twenty-first century because of the long lifetime of the precursor molecules.

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GSWP-2: Multimodel Analysis and Implications for Our Perception of the Land Surface

Bulletin of the American Meteorological Society ◽

10.1175/bams-87-10-1381 ◽

2006 ◽

Vol 87 (10) ◽

pp. 1381-1398 ◽

Cited By ~ 458

Author(s):

Paul A. Dirmeyer ◽

Xiang Gao ◽

Mei Zhao ◽

Zhichang Guo ◽

Taikan Oki ◽

...

Keyword(s):

Land Surface ◽

Good Description ◽

Regional Scale ◽

Co2 Concentration ◽

Atmospheric Measurements ◽

Modeling Tools ◽

Sources And Sinks ◽

Spatial Gradients ◽

Continental Scale ◽

Regional Flow

Quantification of sources and sinks of carbon at global and regional scales requires not only a good description of the land sources and sinks of carbon, but also of the synoptic and mesoscale meteorology. An experiment was performed in Les Landes, southwest France, during May–June 2005, to determine the variability in concentration gradients and fluxes of CO2 The CarboEurope Regional Experiment Strategy (CERES; see also http://carboregional.mediasfrance.org/index) aimed to produce aggregated estimates of the carbon balance of a region that can be meaningfully compared to those obtained from the smallest downscaled information of atmospheric measurements and continental-scale inversions. We deployed several aircraft to sample the CO2 concentration and fluxes over the whole area, while fixed stations observed the fluxes and concentrations at high accuracy. Several (mesoscale) meteorological modeling tools were used to plan the experiment and flight patterns. Results show that at regional scale the relation between profiles and fluxes is not obvious, and is strongly influenced by airmass history and mesoscale flow patterns. In particular, we show from an analysis of data for a single day that taking either the concentration at several locations as representative of local fluxes or taking the flux measurements at those sites as representative of larger regions would lead to incorrect conclusions about the distribution of sources and sinks of carbon. Joint consideration of the synoptic and regional flow, fluxes, and land surface is required for a correct interpretation. This calls for an experimental and modeling strategy that takes into account the large spatial gradients in concentrations and the variability in sources and sinks that arise from different land use types. We briefly describe how such an analysis can be performed and evaluate the usefulness of the data for planning of future networks or longer campaigns with reduced experimental efforts.

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Assimilation of IASI partial tropospheric columns with an Ensemble Kalman Filter over Europe

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-2513-2012 ◽

2012 ◽

Vol 12 (5) ◽

pp. 2513-2532 ◽

Cited By ~ 28

Author(s):

A. Coman ◽

G. Foret ◽

M. Beekmann ◽

M. Eremenko ◽

G. Dufour ◽

...

Keyword(s):

Kalman Filter ◽

Air Quality ◽

Tropospheric Ozone ◽

General Circulation ◽

Surface Ozone ◽

Lower Sensitivity ◽

Free Troposphere ◽

Radiative Balance ◽

Continental Scale ◽

The Mediterranean

Abstract. Partial lower tropospheric ozone columns provided by the IASI (Infrared Atmospheric Sounding Interferometer) instrument have been assimilated into a chemistry-transport model at continental scale (CHIMERE) using an Ensemble Square Root Kalman Filter (EnSRF). Analyses are made for the month of July 2007 over the European domain. Launched in 2006, aboard the MetOp-A satellite, IASI shows high sensitivity for ozone in the free troposphere and low sensitivity at the ground; therefore it is important to evaluate if assimilation of these observations can improve free tropospheric ozone, and possibly surface ozone. The analyses are validated against independent ozone observations from sondes, MOZAIC1 aircraft and ground based stations (AIRBASE – the European Air quality dataBase) and compared with respect to the free run of CHIMERE. These comparisons show a decrease in error of 6 parts-per-billion (ppb) in the free troposphere over the Frankfurt area, and also a reduction of the root mean square error (respectively bias) at the surface of 19% (33%) for more than 90% of existing ground stations. This provides evidence of the potential of data assimilation of tropospheric IASI columns to better describe the tropospheric ozone distribution, including surface ozone, despite the lower sensitivity. The changes in concentration resulting from the observational constraints were quantified and several geophysical explanations for the findings of this study were drawn. The corrections were most pronounced over Italy and the Mediterranean region, we noted an average reduction of 8–9 ppb in the free troposphere with respect to the free run, and still a reduction of 5.5 ppb at ground, likely due to a longer residence time of air masses in this part associated to the general circulation pattern (i.e. dominant western circulation) and to persistent anticyclonic conditions over the Mediterranean basin. This is an important geophysical result, since the ozone burden is large over this area, with impact on the radiative balance and air quality. 1 Measurements of OZone, water vapour, carbon monoxide and nitrogen oxides by in-service AIrbus airCraft (http://mozaic.aero.obs-mip.fr/web/).

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Multiannual changes of CO<sub>2</sub> emissions in China: indirect estimates derived from satellite measurements of tropospheric NO<sub>2</sub> columns

Atmospheric Chemistry and Physics ◽

10.5194/acp-13-9415-2013 ◽

2013 ◽

Vol 13 (18) ◽

pp. 9415-9438 ◽

Cited By ~ 28

Author(s):

E. V. Berezin ◽

I. B. Konovalov ◽

P. Ciais ◽

A. Richter ◽

S. Tao ◽

...

Keyword(s):

Time Series ◽

Co2 Emission ◽

Emission Inventory ◽

Emission Inventories ◽

Satellite Measurements ◽

Top Down ◽

Global Emission ◽

Tropospheric No2 ◽

Emission Changes ◽

Emission Ratios

Abstract. Multiannual satellite measurements of tropospheric NO2 columns are used for evaluation of CO2 emission changes in China in the period from 1996 to 2008. Indirect top-down annual estimates of CO2 emissions are derived from the satellite NO2 column measurements by means of a simple inverse modeling procedure involving simulations performed with the CHIMERE mesoscale chemistry–transport model and the CO2-to-NOx emission ratios from the Emission Database for Global Atmospheric Research (EDGAR) global anthropogenic emission inventory and Regional Emission Inventory in Asia (REAS). Exponential trends in the normalized time series of annual emissions are evaluated separately for the periods from 1996 to 2001 and from 2001 to 2008. The results indicate that the both periods manifest strong positive trends in the CO2 emissions, and that the trend in the second period was significantly larger than the trend in the first period. Specifically, the trends in the first and second periods are best estimated to be in the range from 3.7 to 8.3 and from 11.0 to 13.2% per year, respectively, taking into account statistical uncertainties and differences between the CO2-to-NOx emission ratios from the EDGAR and REAS inventories. Comparison of our indirect top-down estimates of the CO2 emission changes with the corresponding bottom-up estimates provided by the EDGAR (version 4.2) and Global Carbon Project (GCP) glomal emission inventories reveals that while acceleration of the CO2 emission growth in the considered period is a common feature of both kinds of estimates, nonlinearity in the CO2 emission changes may be strongly exaggerated in the global emission inventories. Specifically, the atmospheric NO2 observations do not confirm the existence of a sharp bend in the emission inventory data time series in the period from 2000 to 2002. A significant quantitative difference is revealed between the bottom-up and indirect top-down estimates of the CO2 emission trend in the period from 1996 to 2001 (specifically, the trend was not positive according to the global emission inventories, but is strongly positive in our estimates). These results confirm the findings of earlier studies that indicated probable large uncertainties in the energy production and other activity data for China from international energy statistics used as the input information in the global emission inventories. For the period from 2001 to 2008, some quantitative differences between the different kinds of estimates are found to be in the range of possible systematic uncertainties associated with our estimation method. In general, satellite measurements of tropospheric NO2 are shown to be a useful source of information on CO2 sources collocated with sources of nitrogen oxides; the corresponding potential of these measurements should be exploited further in future studies.

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