4.2. Impact of Industrial Transfer on Haze Pollution
Based on the model settings described above, an OLS analysis of the impact of the overall industrial transfer status on the haze pollution of each province was conducted, with the results shown in
Table 4. The spatial relativity of the model residuals was then analyzed.
The regression results presented in
Table 4 show that the overall industrial transfer level and scale have no significant effect on haze pollution. However, as shown in
Figure 4, the OLS regression residuals has a significant spatial correlation, and therefore, the OLS analysis could not objectively display the relationship between variables. To improve the accuracy of the estimation, spatial panel measurements were employed in the analysis and the spatial correlations between provinces were taken into consideration. Prior to the spatial panel model regression, a spatial correlation test of the dependent variable
lnPM10 was conducted, with the test results showing a significant spatial correlation (see
Table 5).
To explore the relationship between the overall industrial manufacturing transfer and haze pollution, the overall industrial transfer level and scale were adopted respectively. The SEM, SAR, SAC, and SDM were used in the analysis. A Hausman test was used to select the fixed effect spatial panel model (Taking the SDM as an example to explore the effect of industrial transfer on smog pollution, i.e., model (6), a Hausman test produced: chi2 (10) = 227.82, with a
p value of 0.0000. When the effect of transfer scale on smog pollution was considered, i.e., model (10), a Hausman test produced: chi2(10) = 184.15, with a p value of 0.0000. The original hypothesis was rejected in both cases and the fixed effect model was selected.), with the results shown in
Table 6.
Among models (3)–(10), a number of regression coefficients for SDM are significant in the fitting. A Wald test and LR were used to further test the fitting effect of the SDM and the original hypothesis was rejected after considering the test result (When exploring the impact of the overall industrial transfer level on smog pollution, the Wald test result is chi2 (10) = 38.86, with a p value of 0.0000; the L ratio test statistical result is chi2(10) = 45.23, with a p value of 0.0000. When exploring the impact of the overall industrial transfer scale on smog pollution, the Wald test result is chi2 (10) = 40.21, with a p value of 0.0000; the L ratio test statistical result is chi2 (10) = 43.63, with a p value of 0.0000.). When combined with the natural logarithmic values of each model, it is considered that the SDM has the best fitting effect, i.e., the influence of the two spatial conduction mechanisms of haze pollution contained in the SDM could not be ignored. Based on this, the SDM was selected for use in the analysis.
The results in
Table 6 show that, whether measured by the industrial transfer level or the industrial transfer scale, the spatial lag coefficient is dramatically positive. This is further proof that the haze pollution in China has obvious spatial agglomeration characteristics. Taking the results of model (6) for example, every 1% increase in the PM
10 concentration in a neighboring province will contribute to a 0.3% increase across the region. Hence prevention and control of haze should be a joint responsibility for the region. The leakage effect of haze pollution prevents unilateral haze governance from achieving the desired results. Models (6) and (10) produce different values of the independent coefficient, but the symbol and level of significance are basically consistent. The influence of various factors is analyzed and is explained in the following paragraphs:
(1) Industrial transfer. The level and scale of industrial transfer are both positively related to haze pollution. According to regional economic theory, industrial transfer not only promotes regional economic integration, but also alleviates the problem of central city resources and environmental pollution. Measured from either the level or scale of industrial transfer, the results of this study prove that the transfer of industrial manufacturing makes haze pollution more severe in areas where polluting industry is relocated too and to some extent alleviates the problem of industrial haze pollution in the original location. As the main region of outbound industrial transfer, the eastern developed areas have experienced an effective alleviation of haze pollution due to the large-scale transfer of industrial manufacturing. However, the transfer of industrial manufacturing will slow down the pace of local economic development. The transfer of secondary industry can effectively alleviate the dependence of local economic development on these industries, promoting the development of high tech industries, and forcing long term industrial transformation. This will not only optimize the industrial structure and create new economic growth points, but will also effectively alleviate regional environmental pressures.
Although haze pollution in areas where outbound industrial transfer is occurring can be effectively alleviated due to the transfer of industrial manufacturing, from the national perspective, industrial transfer cannot effectively control haze pollution, but would only enable its spatial redistribution. With the environmental cost incurred by the eastern cities increasing annually, some industrial manufacturing industries, especially polluting industries, have been actively shifting to the central and western regions through the implementation of policies and government interests. Central and western provinces are also actively promoting the transfer-in of eastern industries to provide opportunities for development. China has a vast territory, but there is a serious imbalance in the development of various regions. However, as China’s economy further develops, industrial transformation and the upgrading of various provinces and regions are only a matter of time. The central and western provinces have only considered economic development when undertaking industrial transfer. An overreliance on industrial manufacturing, especially polluting industries, will not achieve sustainable economic development. To alleviate the impact of polluting industries on the quality of the local atmospheric environment, the government should undertake a comprehensive consideration of the impact of enterprises on the regional economy and environment, encourage enterprises to research and develop technologies for green production, and also provide corresponding subsidies and preferential policies.
(2) Population density. Population density has a significant effect on haze pollution. Demand for housing and transportation has increased as the population density has increased, which has directly and indirectly exacerbated haze pollution in the region. With an ever-increasing population density, local haze pollution can be alleviated by improving the efficiency of urban resource utilization and sharing facilities for pollution reduction. However, the positive externalities generated by population concentration have yet to be fully utilized, which is also an issue that the government should consider in future urban construction.
(3) Level of economic development. A negative correlation between the level of provincial economic development and haze pollution is identified, but the relationship is not significant whether measured from per capita GDP or lighting brightness (due to the possible multiple collinearity problem, when measuring the level of economic development in terms of per capita GDP and lighting brightness, a multi-collinearity test was conducted. The result is VIF = 2.89, indicating that there is no significant multicollinearity.). Based on data from 1998 to 2012, Shao et al. [
45] discovered that the economic growth level and the haze pollution have a “U”-shaped relationship; some provinces have already exceeded the inflection point and arrived at the stage where the economic growth level is negatively related to haze pollution. Based on data from 2008 to 2016, it was found that the current level of economic development does not have an obvious effect on haze pollution; in contrast, it could alleviate the degree of local haze pollution. Although haze pollution is still persistent due to economic development, the results indicate that China has entered the stage where haze pollution and economic growth have become decoupled.
(4) Energy mix. Energy mix and haze pollution are positively correlated. Because China’s energy mix is dominated by coal [
61], pollutants such as soot and SO
2 that are released from coal burning are direct sources of haze. Coal accounts for as much as 70% of China’s energy consumption; however, the growth in coal consumption has increased haze pollution. To alleviate the impact of excessive coal consumption on haze pollution, the Chinese government should adopt policies such as actively guiding people to use green energy, and adjust the national energy consumption structure to move toward a green structure.
(5) Vehicle use. The local vehicle use is significantly positively correlated with the level of haze pollution. Provinces with convenient transportation links and a developed road system will have more motor vehicles and more exhaust gas emissions; hence, higher concentrations than provinces with poor transportation. Transportation is one of the main factors influencing haze pollution, and therefore the control of motor vehicle exhaust emissions would be an effective measure to alleviate local haze pollution. The construction of a convenient public transportation system and the widespread use of alternative energy vehicles would also be an effective means to alleviate haze pollution.
(6) Level of environmental regulation. Results from other spatial measurement models have shown that environmental regulation can significantly reduce haze pollution, but according to results gained from the SDM, environmental regulation can alleviate haze pollution levels, although the effect is not statistically significant. In this study, this variable was measured in various regions from the perspective of the implementation of environmental regulations, and it was found that such regulations do not fully meet their expectations. The investment output to alleviate industrial pollution is insufficient, and it is necessary to increase investment in industrial pollution control by the relevant government departments. Despite the insignificant effect of environmental regulations on haze pollution, the role of environmental regulation in the control of haze pollution cannot be ignored. Compared with remediation after the occurrence of haze pollution, it is better to prevent it from happening. All provinces and autonomous regions should formulate corresponding environmental protection regulations according to the local conditions, restrict the activity of enterprises that emit large amounts of dust and polluting gases, implement effective pollution gas emission standards, encourage cleaner production, enhance post-production supervision, appropriately raise the penalty for defaulting, and ensure the sustainable development of enterprises and regions.
(7) Industrial structure. The main factors causing haze pollution in China are the industrial structure, which is based on the secondary industry, and the extensive industrial development model. Some provinces still follow the development path of “pollution first and treatment later,” and the promotion of GDP is still a key factor that encourages local governments to ignore environmental problems and pursue economic benefits. The eastern region has recognized the disadvantages of pursuing economic development and neglecting environmental quality, and has shifted some industries to the central and western regions while eliminating outdated production methods. This has effectively alleviated haze pollution. From a global perspective, accelerating the upgrading of China’s industrial structure, supporting green industries, increasing the proportion of tertiary industry, and guiding the arrival of the post-industrial era in China are the main measures that will alleviate haze pollution.
(8) Meteorological conditions. Meteorological conditions in different provinces have different impacts on haze pollution. A high level of rainfall will decrease the PM
10 concentration. Rainfall has a flushing effect on atmospheric pollution; thus, there are very few haze events in areas with high rainfall levels. However, in areas with relatively high levels of humidity, haze pollution is more serious [
62]. In the fifth meeting of the 12th National Committee of the Chinese People’s Political Consultative Conference in 2017, the policy of “Attaching Great Importance to the Influence of Relative Humidity on Haze Pollution” was proposed, which indicates that high levels of relative humidity could accelerate the formation and transformation of haze.
Where there is a spatial spillover effect, changes in various influencing factors will not only affect local haze pollution, but also the level of haze pollution in neighboring provinces, causing a series of changes through feedbacks. The estimated coefficients of the SDM could directly reflect the influence of the independent variables on haze pollution. Usually the value of the direct effect is smaller than the estimated value of the coefficient. The influence of various influencing factors on haze pollution were decomposed into direct and indirect effects (i.e., spatial spillover effects) [
37]. The direct effect refers to the total impact of a certain influencing factor on the local haze pollution level, including the spatial feedback effect. The indirect effect refers to the influence of a change in a local factor change on the level of haze pollution in the adjacent area. The results of the specific decomposition are presented in the
Table 7.
As can be seen from the decomposition results, industrial transfer has a significant effect on haze pollution. Although the spatial spillover effect of industrial transfer is not statistically significant, its indirect effect accounts for more than 80% of the total effect. The effect of haze pollution in the region cannot be ignored. In addition, population density, energy mix, vehicle use, industrial structure, and relative humidity are important causes of haze pollution. The spatial spillover effect coefficient is positively related to population density and vehicle use, which means that through the spatial spillover effect, the population density and vehicle use in neighboring provinces will increase the level of haze pollution in a specific province.
The level of economic development and precipitation amount can partially alleviate local haze pollution. The decomposition factors of economic development level, measured by per capita GDP and lighting brightness, indicate that the level of economic development directly mitigates the level of haze pollution in a specific region, although this effect is not significant and the coefficient is low. This indicates that the developed regions in China have gradually entered the stage where haze pollution and economic development are decoupled, which has been mainly achieved by transferring low-end industries to adjacent provinces while the high-end industries were retained and developed. The leakage of pollution from the industrial transfer allows the transferring provinces to continue their economic development, while alleviating local haze pollution. From a regional perspective, industries transferred out of developed regions can not only ease haze pollution, but also promote industrial transformation and upgrading. Although affecting the level of economic development in the short term, it will promote local economic development in the long run. However, from the national perspective, industrial relocation cannot eradicate haze pollution. If the main influencing factors are not controlled, industrial transfer becomes the last resort for alleviating haze pollution.
Environmental regulation has not played a direct role in suppressing haze pollution. The spatial spillover effect of environmental regulation may increase the level of haze pollution in neighboring provinces. This is because the expected environmental regulations are not realized due to imposition of environmental policies in neighboring provinces and concerns over the competitiveness of local industry.