Carbon and air pollutant emissions from China's cement industry 1990-2015: Trends, evolution of technologies, and drivers

Abstract

China is the largest cement producer and consumer in the world. Cement manufacturing is highly energyintensive and is one of the major contributors to carbon dioxide (CO2) and air pollutant emissions, which threatens climate mitigation and air quality improvement. In this study, we investigated the decadal changes in carbon dioxide and air pollutant emissions for the period of 1990 2015 based on intensive unit-based information on activity rates, production capacity, operation status, and control technologies which improved the accuracy of the cement emissions in China. We found that, from 1990 to 2015, accompanied by a 10.3-fold increase in cement production, CO2, SO2, and NOx emissions from China's cement industry increased by 627 %, 56 %, and 659 %, whereas CO, PM2:5, and PM10 emissions decreased by 9 %, 63 %, and 59 %, respectively. In the 1990s, driven by the rapid growth of cement production, CO2 and air pollutant emissions increased constantly. Then, the technological innovation in production of replacing traditional shaft kilns with the new precalciner kilns equipped with highefficiency control facilities in the 2000s markedly reduced SO2, CO, and PM emissions in the cement industry. In 2010, nationwide, 39 % and 31 % of the nationwide PM2:5 and NOx emission were produced by 3 % and 15 % of the total capacity of the production lines, indicating the disproportionately high emissions from a small number of the super-polluting units. Since 2010, the growing trend of emissions has been further curbed by a combination of measures, including promoting large-scale precalciner production lines and phasing out small ones, upgrading emission standards, installing low NOx burners (LNB), and selective non-catalytic reduction (SNCR) to reduce NOx emissions, as well as adopting more advanced particulate matter control technologies. Our study highlights the effectiveness of advanced technologies on air pollutant emission control; however, CO2 emissions from China's cement industry kept growing throughout the period, posing challenges to future carbon emission mitigation in China.