RESUMO
The emission reduction effect of major air pollution control measures on PM2.5 concentrations was assessed using air quality simulations based on the calculation data of emission reductions from different air pollution control measures and the high spatiotemporal resolution online monitoring data of PM2.5 during the 13th Five-Year Period in Tianjin. The results showed that the total emission reductions of SO2, NOx, VOCs, and PM2.5 from 2015 to 2020 were 4.77×104, 6.20×104, 5.37×104, and 3.53×104 t, respectively. SO2 emission reduction was mainly due to the prevention of process pollution, loose coal combustion, and thermal power. NOx emission reduction was mainly due to the prevention of process pollution, thermal power, and steel industry. VOCs emission reduction was mainly due to prevention of process pollution. PM2.5 emission reduction was mainly due to the prevention of process pollution, loose coal combustion, and the steel industry. The concentrations, pollution days, and heavy pollution days of PM2.5 decreased significantly from 2015 to 2020 by 31.4%, 51.2%, and 60.0% compared to those in 2015, respectively. The concentrations and pollution days of PM2.5 decreased slowly in the later stage (from 2018 to 2020)as compared with those in the early stage (from 2015 to 2017), and the days of heavy pollution remained for approximately 10 days. The results of air quality simulations showed that meteorological conditions contributed one-third to the reduction in PM2.5 concentrations, and the emission reductions of major air pollution control measures contributed two-thirds to the reduction in PM2.5 concentrations. For all air pollution control measures from 2015 to 2020, PM2.5 concentrations were reduced by the prevention of process pollution, loose coal combustion, the steel industry, and thermal power by 2.66, 2.18, 1.70, and 0.51 µg·m-3, respectively, accounting for 18.3%, 15.0%, 11.7%, and 3.5% of PM2.5 concentration reductions. In order to promote the continuous improvement in PM2.5 concentrations during the 14th Five-Year Plan period, under the total coal consumption control and the goal of "peaking carbon dioxide emissions and achieving carbon neutrality," Tianjin should continue to optimize and adjust the coal structure and further promote the coal consumption to the power industry with an advanced pollution control level. At the same time, it is necessary to further improve the emission performance of industrial sources in the whole process, taking environmental capacity as the constraint; design the technical route for industrial optimization, adjustment, transformation, and upgrading; and optimize the allocation of environmental capacity resources. Additionally, the orderly development model for key industries with limited environmental capacity should be proposed, and clean upgrading, transformation, and green development should be guided for enterprises.
RESUMO
Based on the STIRPAT model, this study quantitatively analyzed the synergistic effect of pollution reduction and carbon reduction in Tianjin from three dimensions:total emission, emission reduction, and synergy coefficient. The results showed that the main emission sources of air pollutants and greenhouse gases in Tianjin were industrial sources, and the Pearson correlation coefficient of air pollutants and greenhouse gases was 0.984. The total population, urbanization rate, gross regional product, energy intensity, and carbon dioxide emission intensity were important factors affecting the synergistic effect of pollution reduction and carbon reduction in Tianjin. In 2011 and 2012, Tianjin's air pollutants and greenhouse gas emissions increased synergistically, and the synergistic effect coefficients were 0.18 and 0.17, respectively. From 2013 to 2014 and from 2018 to 2023, the air pollutant emission reduction and greenhouse gas emission increased, the synergistic effect coefficient was less than 0, and the pollution reduction and carbon reduction had no synergistic effect. In 2015-2017 and 2024-2060, air pollutants and greenhouse gas emissions were predicted to be reduced at the same time, with a synergistic effect coefficient ranging from 2.74 to 8.76. Tianjin had the conditions to enter the synergistic stage of pollution reduction and carbon reduction in 2024. The most important things for Tianjin to do to promote the synergy of pollution reduction and carbon reduction were to strictly control the total amount of greenhouse gas emissions, continue to promote the reduction in energy intensity and carbon dioxide emission intensity, and reasonably control the total population, urbanization rate, and regional GDP.