The Driving Influence of Multi-Dimensional Urbanization on PM2.5 Concentrations in Africa: New Evidence from Multi-Source Remote Sensing Data, 2000–2018

Abstract

Africa’s PM2.5 pollution has become a security hazard, but the understanding of the varying effects of urbanization on driven mechanisms of PM2.5 concentrations under the rapid urbanization remains largely insufficient. Compared with the direct impact, the spillover effect of urbanization on PM2.5 concentrations in adjacent regions was underestimated. Urbanization is highly multi-dimensional phenomenon and previous studies have rarely distinguished the different driving influence and interactions of multi-dimensional urbanization on PM2.5 concentrations in Africa. This study combined grid and administrative units to explore the spatio-temporal change, spatial dependence patterns, and evolution trend of PM2.5 concentrations and multi-dimensional urbanization in Africa. The differential influence and interaction effects of multi-dimensional urbanization on PM2.5 concentrations under Africa’s rapid urbanization was further analyzed. The results show that the positive spatial dependence of PM2.5 concentrations gradually increased over the study period 2000–2018. The areas with PM2.5 concentrations exceeding 35 μg/m3 increased by 2.2%, and 36.78% of the African continent had an increasing trend in Theil–Sen index. Urbanization was found to be the main driving factor causing PM2.5 concentrations changes, and economic urbanization had a stronger influence on air quality than land urbanization or population urbanization. Compared with the direct effect, the spillover effect of urbanization on PM2.5 concentrations in two adjacent regions was stronger, particularly in terms of economic urbanization. The spatial distribution of PM2.5 concentrations resulted from the interaction of multi-dimensional urbanization. The interaction of urbanization of any two different dimensions exhibited a nonlinear enhancement effect on PM2.5 concentrations. Given the differential impact of multi-dimensional urbanization on PM2.5 concentrations inside and outside the region, this research provides support for the cross-regional joint control strategies of air pollution in Africa. The findings also indicate that PM2.5 pollution control should not only focus on urban economic development strategies but should be an optimized integration of multiple mitigation strategies, such as improving residents’ lifestyles, optimizing land spatial structure, and upgrading the industrial structure.

Has Industrial Upgrading Improved Air Pollution?—Evidence from China’s Digital Economy

“…To broadly explore the spatial-temporal evolution of air pollution, the perspectives include emission inventories of air pollutants [12], source analysis of particulate matter [5], and spatialtemporal evolution and prediction of air pollution from differentiated data sources [11,13]. The selected research objects include single air pollutants, such as SO 2 [14,15], NO 2 [16,17], O 3 [18,19], PM 10 [20,21], and PM 2.5 [22,23], and composite indices, such as API [24] and AQI [25]. The spatial scales of the studies are mainly focused on the national scale [3], provincial scale [26], urban clusters [11], and urban scale [27].…”

Spatial and nonlinear effects of new-type urbanization and technological innovation on industrial carbon dioxide emission in the Yangtze River Delta

“…First of all, most of the current research attempts to quantify new-type urbanization from the perspectives of population urbanization (Yanna et al 2022), spatial urbanization (Zhang et al 2022a), ecological environment (Sun 2017), social indicator (Lin and Zhu 2021), urban-rural coordination (Wu et al 2022), using the entropy method (Li et al 2021a), factor analysis and principal component analysis method (Shi et al 2020), comprehensive index method of fully arranged polygons (Deng 2021), and improved TOPSIS method (Rao and Gao 2022) to quantify new-type urbanization. Secondly, among the studies of the impact on the ecological environment, the increase of PM2.5 concentration (Wei et al 2021), the reduction of energy intensity (Lin and Zhu 2021), the reduction of per capita carbon emissions (Wang et al 2021), and the decreasing of haze pollutions (Han and Cao 2022) are mainly deemed significantly associated with the increase in the level of new-type urbanization. And there are studies focus on the spatial correlation of newtype urbanization.…”

The Direct and Spillover Effect of Multi-Dimensional Urbanization on PM2.5 Concentrations: A Case Study from the Chengdu-Chongqing Urban Agglomeration in China

“…Aside from urbanization, the accumulation and dispersion of PM 2.5 are affected by factors, such as land-use types, meteorological conditions and degree of forest coverage [14,35]. For example, Duan et al [36] found that the PM 2.5 concentrations of Lushan Mountain in China vary due to the altitude and slope.…”