Alterations in cytosol free calcium in horseradish roots simultaneously exposed to lanthanum(III) and acid rain.

The extensive use of rare earth elements (REEs) has increased their environmental levels. REE pollution concomitant with acid rain in many agricultural regions can affect crop growth. Cytosol free calcium ions (Ca(2+)) play an important role in almost all cellular activities. However, no data have been reported regarding the role of cytosol free Ca(2+) in plant roots simultaneously exposed to REE and acid rain. In this study, the effects of exposures to lanthanum(III) and acid rain, independently and in combination, on cytosol free Ca(2+) levels, root activity, metal contents, biomass, cytosol pH and La contents in horseradish roots were investigated. The simultaneous exposures to La(III) and acid rain increased or decreased the cytosol free Ca(2+) levels, depending on the concentration of La(III), and these effects were more evident than independent exposure to La(III) or acid rain. In combined exposures, cytosol free Ca(2+) played an important role in the regulation of root activity, metal contents and biomass. These roles were closely related to La(III) dose, acid rain strength and treatment mode (independent exposure or simultaneous exposure). A low concentration of La(III) (20 mg L(-1)) could alleviate the adverse effects on the roots caused by acid rain, and the combined exposures at higher concentrations of La(III) and acid rain had synergic effects on the roots.

Analysis of the spatial effect of outward foreign direct investment on air pollution: evidence from China.

Outward foreign direct investment (OFDI) plays a pivotal role in the strategy to build a high-level and open economy. This research used spatial panel models and data from 30 provinces in China from 2004 to 2017 to empirically analyse the relationship between OFDI and air pollution. The results revealed that, first, China's air pollution showed two spatial clustering areas: the eastern coastal area (e.g. Zhejiang) and the north-western area (e.g. Xinjiang). Second, with the increase in OFDI, the direct effect on the concentration of respirable suspended particulate matter (PM10) and sulphur dioxide (SO2) was negative, and the direct effect on nitrogen dioxide (NO2) was positive; however, the total effect was negative. An increase of 1% in OFDI would directly decrease the concentrations of PM10 and SO2 by 0.024% and 0.096%, respectively, while NO2 would directly increase by 0.061%, but the total effect of OFDI on the three air pollutants was negative. Third, the environmental Kuznets curve hypothesis existed between economic growth and SO2 and NO2 but not between economic growth and PM10. The spatial panel model results revealed that the spatial spillover effects of air pollutants (i.e. PM10, SO2, and NO2) were 0.494, 0.447 and 0.314, respectively. Moreover, the impact of OFDI on air pollution had significant temporal heterogeneity. To make the results robust, this research conducted a robustness test by replacing the spatial weight matrix and dependent variables. Finally, the conclusion of this article demonstrates the importance of OFDI in improving air pollution, and we could benefit from OFDI. Our research conclusions provide an important reference for policymakers in implementing trade policies and improving air pollution.

Air pollution and income distribution: evidence from Chinese provincial panel data.

In recent years, air pollution has caused an increasing number of problems in China. Individual health and labour productivity, which are affected by air pollution may affect income distribution. Therefore, this article will analyse the effect of air pollution on income distribution. We investigated the evolution of air pollution in China over the past two decades. Fixed-effects and random-effects estimation approaches were used with data from 30 provinces in China from 1998 to 2017 to analyse the effect of air pollution on income distribution. Empirical results reveal that air pollution significantly worsens income distribution in China. Then we explored the mechanism by which air pollution affects income distribution, and found that increasing health expenditures and declining labour productivity mediate the effect of air pollution on income distribution. Considering the potential endogenous problems of air pollution affecting income distribution, the simultaneous equation model and the instrumental variable approach are employed to overcome endogenous bias. Traditional mean regression was empirically found to overestimate the impact of air pollution on income distribution. Finally, some policy implications are proposed to improve air quality and income distribution.

The nonlinear impact of industrial restructuring on economic growth and carbon dioxide emissions: a panel threshold regression approach.

Energy conservation, emission reduction, and sustainable development are the goals of achieving low-carbon economic development all over the world. Many countries are working hard to find measures, and industrial restructuring is considered to be an effective way to achieve economic development and emission reduction. However, previous studies have assumed that industrial restructuring and economic growth and emissions are simple linear relationships while neglecting nonlinear relationships. We use panel data from 32 countries from 1997 to 2017 and employ panel threshold models (Stochastic Impacts by Regression on Population, Affluence and Technology model and Solow growth model) for empirical test. The results reveal that industrial restructuring has statistically significant nonlinear effects on economic growth and carbon dioxide emissions. With the process of industrialization and urbanization, industrial restructuring has a long-term positive impact on economic growth. The relationship among industrial restructuring and carbon dioxide emissions has been found to be inverted U-shaped. Industrial restructuring is beneficial to reducing emissions. The policy implies that although industrial restructuring is considered to be an effective measure to achieve green growth, for countries with different degrees of urbanization and economic development, industrial structure transformation should adopt different policies.

Heterogeneous role of renewable energy consumption in economic growth and emissions reduction: evidence from a panel quantile regression.

This paper focuses on the heterogeneity of renewable energy consumption and economic growth and emissions by using panel quantile regression models and based on the data from 33 countries during the period of 1990-2016. The approach in this paper is to consider the heterogeneity of the distribution, and results reveal a long-term equilibrium relationship among renewable energy consumption, economic growth and emissions. The role of renewable energy consumption in economic growth and emissions is heterogeneous, and the relationship between renewable energy consumption and economic growth is W-shaped. The relationship between renewable energy consumption and emissions has an inverted N-shape, and the relationship between non-renewable energy consumption and emission is a √-shaped curve. This paper supports the growth hypothesis and EKC. In addition, the energy consumption structure should be changed, and the use of renewable energy should be encouraged. This policy not only meets energy and economic growth demands but also improves environmental quality. In addition, countries with different levels of economic growth and emissions should adopt different policies instead of using the same policy.