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Abstract Anthropogenic emissions of reactive nitrogen (Nr) result in adverse impacts on the ecosystems. Nowhere has that threat been more challenging than in rapidly urbanized China, the world's largest anthropogenic Nr producer. The Nanjing Declaration in 2004 called for global reductions in Nr emissions. To assess China's progress, multisource Nr emissions were evaluated with a quantitative method from 2004 to 2014. The results showed that national Nr emissions had increased with fluctuation over this period, 55–59% of the total Nr emissions were emitted to the atmosphere, and that agricultural production still was the biggest contributor (62–69%). The hotspots were mainly located in the developed and coastal regions that also have high population densities. Urbanization was associated with overall decreases in agricultural Nr emission and increases in industrial and residential Nr emissions. The overall increase in residential Nr emission per capita played a large role in driving the growth of national Nr emission. Continuing urbanization poses a significant challenge to future Nr mitigation for ecosystem sustainability and a range of strategies, covering improvement of N-use efficiency, slowdown of Western China's urbanization, and promotion of low N intensive lifestyle, are proposed that can promote Chinese low-nitrogen development. Graphical abstract Unlabelled Image Highlights • Anthropogenic Nr emissions from China have increased with fluctuation since Nanjing Declaration. • Urbanization has positive and negative two-way effects on Chinese Nr emissions. • Continuing urbanization poses a significant challenge to future Nr mitigation. • Regional Nr emissions possess mitigation potentials with the promotions of low-N strategies. [ABSTRACT FROM AUTHOR]

Housing inequality, where the wealthy hold much more housing than those 5 less so, is common worldwide, but how it correlates with haze pollution and hence air pollution has not been studied to date. Due to the market-oriented and finance-driven evolution of its housing system over the last two decades, housing inequality is particularly prominent in post-reform urban China while air pollution has become an increasingly serious problem too. This study explores the relationship between housing inequality and air pollution using 2002–2009 spatial panel data of 65 Chinese cities, to find that housing inequality contributes to exacerbating air pollution. It is also shown that an excessive demand for real estate development due to the uneven distribution of the housing stock is an important mechanism underlying the correlation between housing inequality and air pollution. In addition, such factors as economic development, city size, urbanization level, industrial structure, and capital stock all have different degrees of impact on the correlation between housing inequality and air pollution. The paper concludes by discussing the policy implications of this research and offering some policy recommendations. Unlabelled Image • Calculate housing inequality index of 65 Chinese cities; • Explore the relationship between housing inequality and haze pollution; • Excess demand of real estate development due to uneven distribution of housing stock is an important mechanism; • Introduce instrumental variables to slove the problem of endogenous problem; • Apply spatial panel data model to capture the spatial correlation and conductivity among cities. [ABSTRACT FROM AUTHOR]