Uncovering the characteristics of air pollutants emission in industrial parks and analyzing emission reduction potential: case studies in Henan, China Industrial parks contribute greatly to China’s economic development while emitting huge air pollutants. It is necessary to study the characteristics of air pollutant emissions in industrial parks. In this study, emission inventories for 11 industrial parks were established. Meanwhile, the source emission and spatial distribution characteristics of the industrial park were analyzed. The cluster analysis was used to classify these parks into ‘4Hs’, ‘Mixed’ and ‘4Ls’ parks. ‘4Hs’, ‘Mixed’ and ‘4Ls’ represent that the levels of energy intensity, economic proportion of energy-intensive industries, coal proportion and pollution performance value are high, medium and low in turn. Then three emission reduction measures were set up to estimate the emission reduction potential and environmental impacts. The results show that: (1) the emissions of SO2, NOx, CO, PM10, PM2.5, VOCs and NH3 of 11 industrial parks in 2017 were 11.2, 23.1, 30.8, 8.3, 3.5, 5.1, and 1.1 kt, respectively. (2) Power plants were the largest source of SO2 and NOx emissions, and industrial processes were the largest emission source of CO, PM10, PM2.5, VOCs and NH3. (3) ‘4Hs’ parks with traditional energy-intensive industries as the leading industries should be the emphasis of air pollutant emission reduction. (4) Through the optimal emission reduction measures, SO2, NOx, PM10, PM2.5 and VOCs were reduced by 81, 46, 51, 46 and 77%, respectively. Environmental impact reductions include 1.6 kt SO2eq acidified gas emissions, 1.4 kt PO43−eq eutrophication substances, 4.2 kt PM10eq atmospheric particulate emissions, 7.0 kt 1,4-DCEeq human toxic substances, and 5.2 kt PM2.5 eq breathing Inorganic. This study is helpful to understand the characteristics of air pollutants emissions in industrial parks and promotes the proposal and implementation of air pollutant emissions reduction strategies. An industrial park is an industrial cluster designed to meet the compatible needs of different organizations in the same area1. China began to attach importance to the establishment and development of industrial parks since the Reform and Opening Policy in the late 1970s. In recent years, the number of industrial parks in China has increased year by year, ranking first in the world. As of 2019, the number of industrial parks in China has increased to 25432. Industrial parks are the engines of economic growth in China, and the output value of industrial parks accounts for more than 60% of the country’s total industrial output values3. Meanwhile, industrial parks have consumed huge amounts of energy and resources, while emitting a variety of air pollutants. The development of green industrial parks has been emphasized in the national strategy of ‘Made in China 2025’4 and ‘Industrial Green Development Plan (2016–2020)’5 issued in 2015, implying that industrial parks had become an important area of air pollution control in China. Therefore, it is particularly urgent to evaluate the air pollutant emissions in industrial parks.Establishment of emission inventory is the first step to grasp the emission characteristics and current status of air pollutant emissions in industrial parks, which will provide the basic emission information for policy-makers to formulate air pollution control strategies. At present, most studies on emission inventories focus on national, regional or provincial scales and specific industry. On the national scale, China’s first NMVOCs (Non-Methane Volatile Organic Compounds) emission inventory was established by Klimont et al.6. Konstantinos et al.7 developed a national annual SO2 emission inventory based on satellite data. On the regional level, Qi et al.8 developed a high-resolution air pollutant emission inventory for Beijing-Tianjin-Hebei region in 2013. Zheng et al.9 developed a highly resolved temporal and spatial Pearl River Delta regional emission inventory for the year 2006. In addition, there are more inventory studies focused on the provincial10,11,12 or city level13,14,15. It is worth noting that the previous results have shown that no matter which province or city, the contribution of industrial sources to air pollutants is particularly prominent, so further analysis of industrial sources is needed. However, the number of studies on air pollutant emissions from industrial parks is relatively small. For example, Gragava and Aggarwal16 established an air pollutant emission inventory for highly industrialized areas in southern India, but they did not analyze the source characteristics of specific industries. Wang et al.17 evaluated the environmental impacts of industrial symbiosis in an energy-intensive industrial park through the life cycle assessment method, in which the emission quantity of air pollutants was indirectly determined. Moreover, there were some studies on the air pollutant emission of chemical parks, but air pollutants are generally limited to VOCs18,19,20.In the aspect of emission inventory in specific industry, previous studies were mainly concentrated on the iron and steel industry21, cement industry22, and coal-fired power industry23. Previous researches have laid the foundation for emission inventories for a single industry, but there were few studies on multiple industries. Industrial parks are gathering places for many different types of industries, so the establishment of park-level emission inventory is of great significance to industrial pollution study.The previous studies of industrial parks mainly concentrated on the topics of energy consumption24,25,26, greenhouse gas mitigation27,28,29,30,31, green circular development32,33, and industrial symbiosis34,35,36. There were few studies on air pollutants in industrial parks, so it is urgent to analyze the air pollutant emissions in industrial parks. By determining the air pollutant emission inventory of these parks, the high-polluting industries in the industrial parks can be identified clearly. Furthermore, it can be reconfirmed that those industries with significant energy consumption also emit larger amounts of air pollutants. The findings of this study can certainly assist the decision-makers as to the priority for combating air pollution within their jurisdiction.Due to the cluster of industries and the difficulty of data collection, the estimation of air pollutant emissions in industrial parks is challenging. To fill this gap, this study used 11 industrial parks as the research object and adopted a bottom-up approach to establish an air pollutant emission accounting framework for industrial parks. At the same time, we selected five indicators related to energy, air pollutants and industrial structure to scientifically classify these 11 industrial parks into three clusters in hierarchical cluster analysis method by SPSS software to discuss the emission characteristics of different types of industrial parks and make corresponding air pollutants reduction policy recommendations. On the basis, the emission reduction path of the industrial park and the emission reduction potential was further explored and estimated. Besides, we estimated the environmental benefits brought by different emission reduction paths. This is an attempt at a park-scale emission inventory that includes multiple industries and an exploration of the emission reduction management of different types of industrial parks.In this study, 11 industrial parks located in Henan Province were selected as the research objects, which were Puyang Economic and Technological Development Zone (PYE), Zhengzhou Economic and Technological Development Zone (ZZE), Kaifeng Economic and Technology Development Zone (KFE), Hongqiqu Economic and Technological Development Zone (HQQE), Hebi Economic and Technology Development Zone (HBE), Xinxiang Economic and Technology Development Zone (XXE), Zhengzhou High & New Technology Industrial Development Zone (ZZH), Anyang High & New Technology Industrial Development Zone (AYH), Xinxiang High-Tech Industrial Development Zone (XXH), Jiaozuo High & New Technology Industrial Development Zone (JZH), Zhengzhou Airport Economy Zone (ZZA). The geographic locations of the 11 industrial parks are shown in Fig. 1. According to China’s pollution survey, the total energy consumption of these 11 industrial parks was 5479 ktce in 2017. The energy consumption of each industrial park along with its contribution to the overall energy usage is shown in Fig. 2. Among these 11 parks, PYE had the highest energy consumption with 1825 ktce, of which bituminous coal accounts for 71% of the total energy consumption, followed by natural gas (23%); HQQE ranked the second with energy consumption of 1570 ktce, in which the consumption of raw coal accounts for the highest proportion (61%), followed by coke (29%); and ZZH ranks the third (964 ktce), in which coal consumption accounts for 61% and natural gas consumption accounts for 38%. In addition, the leading industries of each park and annual GDP of these industrial parks are shown in Table S1. The annual GDP of most industrial parks had little correlation with energy consumption. For example, the energy consumption of PYE was the highest, while the annual GDP was much lower. The reason is that the energy in PYE is mainly consumed by power plants, which contributes less economic output to the industrial park.Figure 1Location of 11 industrial parks in Henan Province. Map was created in ArcGIS Desktop v. 10.2 software. (http://www.esri.com/software/arcgis/arcgis-for-desktop/free-trial).Figure 2The energy consumption and structure of 11 industrial parks and proportion of energy consumption of each park to the overall energy usage in these industrial parks.Emission sources categorizationEmission sources categorization is the beginning of emission inventory accounting. The air pollutant emissions were calculated from the actual production perspective within the administrative boundaries of an industrial park. Due to the relatively high data requirements (such as waste treatment methods and volume) and small contribution on air pollutant emissions, fugitive sources are not included in this study. Based on the sources used for previous national and regional emission accounting and the structural characteristics of industrial parks, this study identified three sources for industrial park air pollutants emissions accounting, including power plants, industrial boilers, and industrial processes. Drawing on the National Economical Industry Classification37 and Technical Guideline for the Development of National Air Pollutant Emission Standards38, the emission sources of industrial process were divided into seven sectors, namely non-metallic mineral products industry (including cement, brick and tile industries), paper industry, textile printing and dyeing industry, ink printing industry, chemical industry, steel industry, and non-ferrous metal industry, as shown in Table S2.Emission estimationAccording to the methods of compiling various inventory issued by the Ministry of Ecology and Environmental Protection of China39,40,41,42,43, this study used the bottom-up emission factor method and material balance method to estimate the emission inventory of 11 national industrial parks in Henan Province. Seven air pollutants, including SO2, NOx, CO, PM10, PM2.5, VOCs and NH3, were calculated in this study. Among them, SO2 emissions from power plants and industrial boilers were calculated by the material balance method due to the available sulfur content of the coal used for combustion. Emissions of SO2 from industrial processes and other pollutants from the three sources were calculated by the emission factor method. The calculation formula for pollutant emissions were as follows:SO2 emissions from power plants and industrial boilers were estimated by the mass balance method9:$$E_{s} = sumlimits_{{i,}} {A_{{i,}} times S_{{i,}} times C times (1 – eta )} .$$In the formula, Es was the SO2 emission (t); i was the fuel type; C was the fuel-based coefficient (C = 16 when burning coal, C = 20 when burning oil, and C = 0.02 when burning natural gas9; A was the annual fuel consumption (t); S was the sulfur content of the fuel; and η was the desulfurization efficiency of SO2.Other pollutants emission from power plants, industrial boilers and industrial processes were estimated by the emission factor method9:$$E_{p} = sumlimits_{{k,m}} {B_{k} times EF_{{p,k,m}} times (1 – eta ) times 10^{{ – 3}} }$$In the formula, Ep was the total amount of pollutant emissions (t); p was the type of pollutant; k was the type of fuel or product; m was the control devices type; Bk was the activity level data (fuel consumption or product output, t); EFp,k,m was emission factors (kg/t); and η was the removal efficiency of control measures. To better identify the spatial characteristics of pollutant emissions in 11 industrial parks, gridded emission inventory of industrial park was established at a resolution of 3 km × 3 km with the Geographic Information System technology. The emissions from power plants, industrial boilers and industrial enterprises are fixed point sources, and the geographic coordinates of enterprises or pollutant outlets were used to spatially allocate pollutant emissions. The results of various pollutants were distributed in a grid of 3 km × 3 km, and emissions from point sources were directly distributed to grid cells based on detailed longitude and latitude information.Activity data and emission factorTo establish the air pollutant emission inventory for industrial parks, we first classified the enterprises in each industrial park into different emission sources, and then collected the corresponding activity data and emission factor of individual enterprises. The activity level data of power plants mainly include energy type, energy consumption, boiler type, and end-of-pipe treatment technology. These data were from field surveys and government-organized pollution surveys. The power plant information of 11 industrial parks was shown in the Table S3. Among them, ZZH had two gas boilers with the largest installed capacity of 390 MW. The emission factor of a power plant was determined by its fuel type and combustion method. The emission factors were mainly derived from Ministry of Ecology and Environment and other literature, as shown in Table S4. Industrial boiler source was the enterprises that uses boilers for industrial production activities. The required activity level data include energy type, energy consumption, equipment type, and end-of-pipe treatment technology. The data of industrial boilers was from field surveys and pollution surveys organized by the government. There were 229 industrial boilers in 11 industrial parks, including 22 coal-fired boilers, 203 gas-fired boilers, 3 biomass boilers, and 1 oil-fired boiler. The source of emission factors of industrial boilers was the same as that of power plants, as shown in Table S5. Industrial processes sources refer to the sources of pollutants emitted into the atmosphere by industrial enterprises in industrial parks during product production and processing44. Activity level data mainly include the types of products produced by the company and the output of products and the installed pollutant removal facilities. These data were mainly derived from the industrial enterprise data of the additional pollution source survey in Henan Province in 2017, and corrected in conjunction with environmental statistics and field surveys. The source emission factors of the industrial process were mainly from the literature, as shown in Table S6.Classification of industrial parks using cluster analysisThe research
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Uncovering the characteristics of air pollutants emission in industrial parks and analyzing emission reduction potential: case studies in Henan, China
