Analysis of anthropogenic nitrogen and its influencing factors in Beijing

Abstract

Human activities have changed the global nitrogen cycle and are continuing to do so at an alarming rate. Cities are particularly important nitrogen sinks due to the concentration of human activities, and have attracted widespread attention. However, researchers disagree about the sink size and the underlying socioeconomic factors. Taking Beijing as an example, we developed an anthropogenic nitrogen index to characterize the sink size and the effects of socioeconomic factors, then we used empirical coefficients for the nitrogen content of materials to calculate the total anthropogenic nitrogen consumption and analyzed its structural characteristics. We used the logarithmic mean divisia index to construct a factor decomposition model and analyze the factors affecting anthropogenic nitrogen consumption and their contribution and direction (promotion or inhibition). Beijing's anthropogenic nitrogen consumption increased from 1995 to 2010 in response to increasing consumption of energy, food, and fertilizer nitrogen. Energy nitrogen accounted for the largest proportion of the total 2 (≥33%) and increased greatly. The proportion of food nitrogen increased from 10% to 21% during the study period. Subsequent decreases in anthropogenic nitrogen mainly resulted from decreased fertilizer nitrogen consumption (to 20% of the total consumption) from 2010 to 2015. Of the influencing factors, the inhibitory effect of material intensity on Beijing's anthropogenic nitrogen consumption increased from 22% to 37% during the study period; the promoting effect of per capita GDP gradually weakened, but its contribution remained >30% of the total. By analyzing the dynamics of Beijing's urban anthropogenic nitrogen consumption, we identified the main socioeconomic drivers, thereby providing scientific support for exploring nitrogen consumption patterns during different urban development stages and for the activities required to regulate nitrogen consumption.

Urban nitrogen budgets: flows and stock changes of potentially polluting nitrogen compounds in cities and their surroundings – a review

“…This becomes evident from some of the trends identified, e.g. by the observed decrease in animal feed (Zhang et al 2020), which just pushes the problem outside city regions. Hence, further coupling of this tool with other scales (province or country) may .…”

“…Another way of normalizing the results from different cities took advantage of the population numbers. Specific flows per capita were derived by Zhang et al (2016Zhang et al ( , 2020) and compared to the results of other available literature. Interpretation, however, was limited due to methodological differences.…”

“…A follow-up analysis of the Beijing situation (Zhang et al 2018) identified structural dependencies between the network's nodes in order to devise paths of impacts, but still did not further resolve their quantities. Partly the same author team performed a factor decomposition analysis for Beijing N flows (Zhang et al 2020) and detected increases over time of energy-and food-related N, while N in fertilizer and animal feed decreased. Specifically, the increase in NO x emissions from transport to almost 80% of energyrelated N input in 2015 (or about 40% of total N input into the city) represented a most decisive change.…”

Dynamic Changes of Nitrogen Loads in Source–Sink Landscapes under Urbanization

“…Cities, with higher population densities and fossil fuel consumption, are hot spots of N pollutants, resulting in environment pollution and public health impacts [5]. Previous studies on N flows and N loads at the city scale have achieved considerable achievements [21][22][23]. These studies have primarily clarified the human activity changes and the spatial distribution of N loads [24,25].…”

Assessment of maternal services in China based on WHO’s comprehensive evaluation model

“…Strengthening the management of maternal to improve the quality and level of maternal health care is an important measure to implement the Healthy China Strategy. At the same time, the impact of economics on maternal mortality is also crucial [15,16]. Inadequate funding, resources, and level of health services can lead to poor access to health services, unreasonable allocation, and under-utilization of resources, which directly affect maternal health and make it unequal across regions.…”