CO emissions in China: Uncertainties and implications of improved energy efficiency and emission control

Abstract

A bottom-up methodology and an improved database of emission factors combining the latest domestic field measurements are developed to estimate the emissions of anthropogenic CO from China at national and provincial levels. The CO emission factors for major economic sectors declined to varying degrees from 2005 to 2009, attributed to improved energy efficiency and/or emission control regulations. Total national CO emissions are estimated at 173 Tg for 2005 and have been relatively stable for subsequent years, despite fast growth of energy consumption and industrial production. While industry and transportation sources dominated CO emissions in developed eastern and north-central China, residential combustion played a much greater role in the less developed western provinces. The uncertainties of national Chinese CO emissions are quantified using Monte Carlo simulation at −20% to +45% (95% confidence interval). Due to poor understanding of emission factors and activity levels for combustion of solid fuels, the largest uncertainties are found for emissions from the residential sector. The trends of bottom-up emissions compare reasonably to satellite observation of CO columns and to ground observations of CO 2 –CO correlation slopes. The increase in the ratio for emissions of CO 2 relative to CO suggests that China has successfully improved combustion efficiencies across its economy in recent years, consistent with national policies to improve energy efficiency and to control criteria air pollutants. ► China's CO emissions are estimated based on a bottom-up method for 2005–2009. ► Improvement of energy efficiency and emission control reduces CO emission factors. ► CO emission trends are consistent with satellite and ground observations. ► Uncertainties come most from residential combustion and non-road transportation.