The role of a peri-urban forest on air quality improvement in the Mexico City megalopolis

2012 ◽  
Vol 163 ◽  
pp. 174-183 ◽  
Author(s):  
Darrel Baumgardner ◽  
Sebastian Varela ◽  
Francisco J. Escobedo ◽  
Alicia Chacalo ◽  
Carlos Ochoa
2020 ◽  
Vol 12 (8) ◽  
pp. 3316 ◽  
Author(s):  
Fang Xu ◽  
Meng Tian ◽  
Jie Yang ◽  
Guohu Xu

The severe air pollution in China has imperiled public health and resulted in substantial economic loss. To tackle the unprecedented pollution challenges, China has launched a campaign-based environmental inspection over all regions to impel local governments’ actual pollution abatement. At the same time, with the public’s awakening awareness about environmental protection, the public has also played a particularly vital role in this inspection. Under this circumstance, the study tries to reveal the impact of Environmental Inspection led by the Central Government (EICG) on air quality improvement, and to examine the role of public engagement in their relationship. Specifically, utilizing daily data covering 249 prefecture-level cities in China from 1 June 2015 to 31 May 2018, this study employed multiple regression models and then found that due to the implementation of EICG, the concentrations of PM2.5, PM10, SO2 and NO2 decline by 2.642 μg/m3, 6.088 μg/m3, 1.357 μg/m3 and 1.443 μg/m3, respectively, and the air quality index decreases by 2.4 in total, which implies that EICG can improve the air quality to a great extent. However, the coefficients for major variables change from negative to positive, suggesting that an attenuation effect of EICG on air quality improvement exists in Chinese institutional background. Meanwhile, public engagement is shown to enhance the positive association between EICG and air quality improvement. Additionally, further analysis demonstrates that EICG promotes the improvement in air quality up to three months after the inspection in cities during the heating period, while the positive effect has existed during one month before the inspection in cities during the non-heating period. Additionally, in contrast to the instant effect in cities not specially monitored, there is a lagged effect of EICG in controlling the air pollution in cities specially monitored.


2020 ◽  
Vol 46 (2) ◽  
pp. 109-134
Author(s):  
Po Ying Lai ◽  
C.Y. Jim ◽  
Hao Zhang

Older trees in good health are expected to provide more ecosystem services and equivalent economic values due to their large size. The relationship of tree dimensions, respective tree height, crown area, diameter at breast height (dbh), and total leaf area vis-a-vis age were studied for 790 heritage trees ≥ 100 years old in Macau; 50 genera and 63 species were represented. Seven out of ten common genera showed no significant increase for all tested parameters except increase of dbh with age. Other factors, such as condition and geometry of growing spaces, controlled the performance of heritage trees, as well as the realization of their biological potential size, with implications on the provision of ecosystem services. The effects of these heritage trees on air-quality improvement and gross carbon sequestration were quantified by the i-Tree Eco model. Overall, 806.8 kg of air pollutants were removed annually, with benefits valued at US $8,091. The heritage trees stored 3,041 t carbon in total and sequestered 842 kg carbon/yr, equivalent to US $601 in annual benefits. The values were much higher than ordinary urban forest trees. Ten common heritage tree genera were ranked by their capacities for air quality improvement, carbon storage, and sequestration. The findings can serve as a decision tool for heritage tree management and conservation and to estimate potential ecosystem services of established trees


2019 ◽  
Vol 48 ◽  
pp. 101548 ◽  
Author(s):  
Vahid Amini Parsa ◽  
Esmail Salehi ◽  
Ahmad Reza Yavari ◽  
Peter M. van Bodegom

2017 ◽  
Vol 17 (1) ◽  
pp. 31-46 ◽  
Author(s):  
Wen Xu ◽  
Wei Song ◽  
Yangyang Zhang ◽  
Xuejun Liu ◽  
Lin Zhang ◽  
...  

Abstract. The implementation of strict emission control measures in Beijing and surrounding regions during the 2015 China Victory Day Parade provided a valuable opportunity to investigate related air quality improvements in a megacity. We measured NH3, NO2 and PM2.5 at multiple sites in and outside Beijing and summarized concentrations of PM2.5, PM10, NO2, SO2 and CO in 291 cities across China from a national urban air quality monitoring network between August and September 2015. Consistently significant reductions of 12–35 % for NH3 and 33–59 % for NO2 in different areas of Beijing during the emission control period (referred to as the Parade Blue period) were observed compared with measurements in the pre- and post-Parade Blue periods without emission controls. Average NH3 and NO2 concentrations at sites near traffic were strongly correlated and showed positive and significant responses to traffic reduction measures, suggesting that traffic is an important source of both NH3 and NOx in urban Beijing. Daily concentrations of PM2.5 and secondary inorganic aerosol (sulfate, ammonium and nitrate) at the urban and rural sites both decreased during the Parade Blue period. During (after) the emission control period, concentrations of PM2.5, PM10, NO2, SO2 and CO from the national city-monitoring network showed the largest decrease (increase) of 34–72 % (50–214 %) in Beijing, a smaller decrease (a moderate increase) of 1–32 % (16–44 %) in emission control regions outside Beijing and an increase (decrease) of 6–16 % (−2–7 %) in non-emission-control regions of China. Integrated analysis of modelling and monitoring results demonstrated that emission control measures made a major contribution to air quality improvement in Beijing compared with a minor contribution from favourable meteorological conditions during the Parade Blue period. These results show that controls of secondary aerosol precursors (NH3, SO2 and NOx) locally and regionally are key to curbing air pollution in Beijing and probably in other mega cities worldwide.


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