Environmental impacts of nitrogen emissions in China and the role of policies in emission reduction

Abstract

Atmospheric reactive nitrogen (N r ) has been a cause of serious environmental pollution in China. Historically, China used too little N r in its agriculture to feed its population. However, with the rapid increase in N fertilizer use for food production and fossil fuel consumption for energy supply over the last four decades, increasing gaseous N r species (e.g. NH 3 and NO x ) have been emitted to the atmosphere and then deposited as wet and dry deposition, with adverse impacts on air, water and soil quality as well as plant biodiversity and human health. This paper reviews the issues associated with this in a holistic way. The emissions, deposition, impacts, actions and regulations for the mitigation of atmospheric N r are discussed systematically. Both NH 3 and NO x make major contributions to environmental pollution but especially to the formation of secondary fine particulate matter (PM 2.5 ), which impacts human health and light scattering (haze). In addition, atmospheric deposition of NH 3 and NO x causes adverse impacts on terrestrial and aquatic ecosystems due to acidification and eutrophication. Regulations and practices introduced by China that meet the urgent need to reduce N r emissions are explained and resulting effects on emissions are discussed. Recommendations for improving future N management for achieving ‘win-win’ outcomes for Chinese agricultural production and food supply, and human and environmental health, are described. This article is part of a discussion meeting issue ‘Air quality, past present and future’.

Alkaline air: changing perspectives on nitrogen and air pollution in an ammonia-rich world

“…Together these changes demonstrate how alkaline air is becoming increasingly important across the UK countryside, in a pattern that is reflected across much of Europe and North America [40,41]. A corresponding trend is now occurring in China, following implementation of SO 2 emission controls from 2012 [42], while in India, NO x emissions have been increasing even faster than NH 3 emissions [43]. The gaseous alkaline fraction (expressed as NH 3 divided by the sum of NH 3 , 2SO 2 , HNO 3 and HCl) is now at 88% in the UK (electronic supplementary material, §4), while estimated global variation is shown in figure 3.…”

Evaluation in Carbon Dioxide Equivalent and CHG Emissions for Water and Energy Management in Water Users Associations. A Case Study in the Southeast of Spain

“…Examples of processes in food production where the use of fossil fuels has contributed the most are mechanization, fertilizer production, processing and transportation. The dependence of the food sector on fossil fuels according to the projections of the Food and Agriculture Organization of the United Nations (FAO) will increase in the coming years, since by 2050 they forecast that food production will increase by 70% to meet demand [20].…”

Global Air Quality, past present and future: an introduction

“…The role of nitrogen compounds on air quality has grown since the mid-twentieth century, especially with the declining role of sulfur dioxide emissions. The papers by Sutton et al [11] and Liu et al [12] both focus on the role of nitrogen compounds. Sutton et al address the issue of ammonia and specifically its role in regulating the acidity of the atmosphere.…”

“…Furthermore, a change in aerosol composition is leading to a change in the partitioning of atmospheric ammonia from aerosol towards the gas phase, leading to a change in transport distance of NH x in the atmosphere and continued dominance of reduced nitrogen in driving effects on ecosystems [4]. The role of reactive nitrogen (N r ) in China is described by Liu et al [12], showing emissions of NH 3 currently exceeding those of NO x by 30% (as N) and playing a major role in the air quality issues in China. Notable reductions of emissions of NOx in China have been achieved over the last decade.…”

“…The role of reactive nitrogen (N r ) in China is described by Liu et al. [12], showing emissions of NH 3 currently exceeding those of NO x by 30% (as N) and playing a major role in the air quality issues in China. Notable reductions of emissions of NOx in China have been achieved over the last decade.…”