Relationship between Air Pollutants and Economic Development of the Provincial Capital Cities in China during the Past Decade

<div><p>With the economic development of China, air pollutants are also growing rapidly in recent decades, especially in big cities of the country. To understand the relationship between economic condition and air pollutants in big cities, we analysed the socioeconomic indictorssuch as Gross Regional Product per capita (GRP per capita), the concentration of air pollutants (PM₁₀, SO₂, NO₂₎ and the air pollution index (API) from 2003 to 2012 in 31 provincial capitals of mainland China. The three main industries had a quadratic correlation with NO₂, but a negative relationship with PM₁₀ and SO₂. The concentration of air pollutants per ten thousand yuan decreased with the multiplying of GRP in the provinical cities. The concentration of air pollutants and API in the provincial capital cities showed a declining trend or inverted-U trend with the rise of GRP per capita, which provided a strong evidence for the Environmental Kuznets Curve (EKC), that the environmental quality first declines, then improves, with the income growth. The results of this research improved our understanding of the alteration of atmospheric quality with the increase of social economy and demonstrated the feasibility of sustainable development for China.</p></div

Concentration of PM₁₀ in cities of different continents.

<p>Concentration of PM₁₀ in cities of different continents.</p

Annual mean concentration of PM₁₀, SO₂ and NO₂ from 2003 to 2012 in different province capitals of mainland China (bar charts on the Chinese map).

<p>Four line charts represent the relationships between annual mean air pollutant and GRP per capita of the East, Central, Northeast and West China respectively from 2003 to 2012.</p

Maps of world PM_2.5 (µg m⁻³) and GRP per capita ($) during 2001 to 2006.

<p>(a) PM_2.5, downloaded from NASA website and reproduced with permission from its authors and publisher (van Donkelaar et al., 2010); (b) GRP per capital, derived from the World Development Indicators of the World Bank (<a href="http://data.worldbank.org/country" target="_blank">http://data.worldbank.org/country</a>).</p

Regression for concentration of PM₁₀, SO₂, NO₂, API and GRP per capita (panel data of all provincial cities).

<p>* P<0.05; ** P<0.01.</p

Air pollutant concentrations as related to the output per capita of three industries in the provincial capitals of China.

<p>(a) The output per capita of the primary industry; (b) The output per capita of the secondary industry; (c) The output per capita of the tertiary industry.</p

Regression for concentration of PM₁₀, SO₂, NO₂ and the three main industries.

<p>* P<0.05; ** P<0.01.</p

Regression curves between GRP per capita and air pollutant index (PM₁₀, SO₂, NO₂, API) in four economic regions during 2003–2012.

<p>The blue line is the regression line and the pink area the 95% confidence limits.</p

GaNb₁₁O₂₉ Nanowebs as High-Performance Anode Materials for Lithium-Ion Batteries

M–Nb–O compounds have been considered as promising anode materials for lithium-ion batteries (LIBs) because of their high capacities, safety, and cyclic stability. However, very limited M–Nb–O anode materials have been developed thus far. Herein, GaNb₁₁O₂₉ with a shear ReO₃ crystal structure and a high theoretical capacity of 379 mAh g^–1 is intensively explored as a new member in the M–Nb–O family. GaNb₁₁O₂₉ nanowebs (GaNb₁₁O₂₉-N) are synthesized based on a facile single-spinneret electrospinning technique for the first time and are constructed by interconnected GaNb₁₁O₂₉ nanowires with an average diameter of ∼250 nm and a large specific surface area of 10.26 m² g^–1. This intriguing architecture affords good structural stability, restricted self-aggregation, a large electrochemical reaction area, and fast electron/Li⁺-ion transport, leading to a significant pseudocapacitive behavior and outstanding electrochemical properties of GaNb₁₁O₂₉–N. At 0.1 C, it shows a high specific capacity (264 mAh g^–1) with a safe working potential (1.69 V vs Li/Li⁺) and the highest first-cycle Coulombic efficiency in all of the known M–Nb–O anode materials (96.5%). At 10 C, it exhibits a superior rate capability (a high capacity of 175 mAh g^–1) and a durable cyclic stability (a high capacity retention of 87.4% after 1000 cycles). These impressive results indicate that GaNb₁₁O₂₉-N is a high-performance anode material for LIBs