Assessment of NO2 Purification by Urban Forests Based on the i-Tree Eco Model: Case Study in Beijing, China

Abstract

Air quality issues caused by nitrogen dioxide (NO2) have become increasingly serious in Chinese cities in recent years. As important urban green infrastructure, urban forests can mitigate gaseous nitrogen pollution by absorbing NO2 through leaf gas exchange. This study investigated spatiotemporal variations in the NO2 removal capacity of urban forests in Beijing city from 2014–2019, based on the i-Tree Eco deposition model. The results show that the annual removal capacity of administrative districts within Beijing city ranged from 14,910 to 17,747 tons, and the largest capacity (2,684 tons) was found in the Fangshan district. The annual removal rate of NO2 by urban forests in administrative districts within Beijing was estimated at between 0.50–1.60 g/m2, reaching the highest (1.47 g/m2) in the Mengtougou district. The annual average absorption of NO2 by urban forests can account for 0.14% - 2.60% of annual total atmospheric NO2 and potentially reduce the NO2 concentration by 0.10 - 0.34 µg/m3 on average. The results of a principal component analysis suggest that the distribution of urban forests in Beijing is not optimized to maximize their NO2 removal capacity, being higher in suburban areas and lower in urban areas. This study provides insights into botanical NO2 removal capacity in Beijing city to mitigate atmospheric N pollution, addressing the key role of urban forests in improving human wellbeing.

Enhancing Urban Above-Ground Vegetation Carbon Density Mapping: An Integrated Approach Incorporating De-Shadowing, Spectral Unmixing, and Machine Learning

“…Urban vegetation, comprising forests, shrubs, and grass, plays a vital role in mitigating atmospheric carbon concentration through processes such as photosynthesis. It contributes to air purification, noise reduction, and climate change impact mitigation [60][61][62][63][64][65][66][67]. The accurate mapping of urban vegetation carbon density is critical for governmental planning and residents' well-being.…”

Valoración económica de los servicios ecosistémicos de cuatro sistemas forestales periurbanos a través de i-Tree Eco

“…En el estudio sobre la mitigación de contaminantes, los datos evidencian una reducción significativa en las concentraciones de ozono en los cuatro sistemas evaluados. Esta tendencia está en línea con los hallazgos de Gong et al (2022), quienes resaltaron la función vital de los árboles en los sistemas urbanos y periurbanos para contrarrestar la presencia del ozono, un contaminante que predomina.…”

Untitled

“…In the course of the study, the feasibility of using one of the tools for assessing the cost of ecosystem functions of i-Tree Eco green spaces in the course of their inventory was tested on the example of the attached part of Rayivskyy landscape park. Based on the results of the study, it was established that the USDA Forest Service (2021) methodology is capable of integration not only into the US green space accounting system, but also into the methods of inventory of plantings in other countries (Raum et al, 2019;Cimburova & Barton, 2020;Gong et al, 2022), including, based on the results of this study, and in the national methodology for inventory of green spaces (Order of..., 2014) by measuring a number of additional biometric indicators of plants. This approach, even if the typical process of performing an inventory of trees and shrubs is slow and complicated, opens up new opportunities for obtaining important information about the ecosystem functions of plantings and the replacement cost of each plant.…”