Optimization Of NO_x Reduction Paths In Guangdong Province Under The Constraint Of Carbon Peaking Target

Owing to the advancement of air pollution control in China,the space for traditional end-of-pipe treatment-based emission reduction is gradually becoming saturated,makes it more difficult to further improvement of air quality,constraints on achieving the target of“Beautiful China”.Currently,ozone pollution is one of the key factors limiting the continuous improvement of air quality in China.The experience of developed countries shows that in the long term,the deep emissions reduction of NOx is the way to control ozone pollution.Meanwhile,General Secretary Xi Jingping proposed in the address to the general debate of the 75th session of the United Nations General Assembly that our carbon dioxide（CO₂）emissions were aiming to reach a peak before2030.Considering that NO_x and CO₂ emissions are of the same origin,in the context of new national strategy of“peak carbon”,It is urgently to conduct research on NO_x reduction pathways constrained by the target of peak carbon.Therefore,this study identifies the drivers of NO_x emissions by building inventories of historical emissions trends for the main NO_x emitting sectors（power sector,industry and transport sector）from 2006-2019;constructs a parametric NO_x emissions prediction model based on the Scalable Stochastic Environmental Impact Assessment Model（STIRPAT）by the driving factors:social-economic-energy-technology;Using scenario analysis in conjunction with predictive modelling,projects the emissions pathways for NO_x and CO₂ for the period 2020-2035;indentifies the optimal NO_x reduction pathway under the carbon peak target constraint in Guangdong Province.The main findings of the study are as follows:（1）The coefficient of determination（R²）of the STIRPAT model for the simulation of historical NO_x emissions from the power,industrial and transport sectors are 0.71,0.68 and 0.71respectively,and the absolute mean errors between the simulated values and the historical NO_xemissions inventories are 7.3%,4.2%and 3.9%,which are good for the simulation of historical emissions.（2）During the period 2006-2019,in Guangdong Province,NO_x emissions showed a trend of first increasing and then decreasing,peaking in 2011,with NO_x emissions intensity showing a rapid decline,dropping from 64.2 tonnes per million yuan to 11.1 tonnes per million yuan,a decrease of82.7%.In terms of sectors,the transportation sector occupied the major share of NO_xemissions（55%）,with NO_x emissions peaking in 2012 and the main sources of emissions being road transport and waterway transport;NO_x emissions from the power sector peaked in 2011,with coal combustion being the main source;NO_x emission from the industrial sector peaked in2008,with coal and oil combustion being the main contributing sources.（3）As for the key drivers of the three sectors,the drivers of NO_x emissions in the transportsector are urbanization rate and road transport structure,while the drivers of NO_x emissions in the power and industry sectors are industrial structure,urbanization rate and the share of coal.In terms of the impact of drivers on NO_x emissions,economic factors,fossil energy factors,industrial structure,transport structure,energy intensity,NO_x end-of-pipe treatment efficiency and motor vehicle NO_x emission factors are positive,while the share of non-fossil energy generation and the share of industrial electricity consumption are negative.（4）The NOx reduction pathway based on scenario analysis shows that under the policy scenario of the 14th Five-Year Plan（abbreviated as the baseline scenario）,NO_x emissions in Guangdong Province will decrease by*%between 2020 and 2035,with NO_x emissions from the power,industry and transport sectors decreasing by 88.6%,67.7%and 35.2%respectively.（5）Without considering the carbon peak target,the largest NO_x emission reduction scenario in Guangdong Province between 2020 and 2035 is that the NOx drivers（GDP of Guangdong,urbanization rate,industrial structure,fossil energy share,road transport structure,NO_x end-of-pipe treatment efficiency,etc.）will progress at a rate higher than that of the 14th Five-Year Plan（abbreviated as the tightening scenario）.In 2035,NO_x emissions are reduced by 63.5%,96.6%in the power sector,82.2%in the industrial sector and 52.5%in the transport sector compared to 2020under the tightened scenario.（6）Under the constraints of the carbon peak target,the optimal NO_x emission reductionscenario in 2020-2035 is as follows:the urbanization rate,industrial structure,transport energy consumption and transport intensity in Guangdong Province maintain the same development rate as the 14th Five-Year Plan,Fossil energy share,energy intensity,NO_x end-of-pipe treatment,road transport structure and other drivers are subject to stricter policy constraints based on the 14th Five-Year Plan（abbreviated as the partial tightening scenario）.The partial tightening scenario will result in a 58.1%reduction in NO_x in Guangdong Province,with 93.6%,74.1%and 47.4%NO_xreductions in the power sector,industry and transport sectors respectively.The results show that although the 14th Five-Year Plan can effectively achieve NO_x emission reduction,on the premise of ensuring the carbon peak and the basis of the 14th Five-Year Plan,accelerating clean energy substitution,reducing energy intensity and vigorously developing"road transport to water transport"can further optimize NO_x emission reduction in Guangdong Province.This study can provide scientific support for the formulation of NOx reduction policies in Guangdong Province in the context of carbon peaking,and provide research references for other regions.