Characteristics and Causes of Ozone Pollution in 16 Cities of Yunnan Plateau

In order to study the characteristics and causes of ozone (O3) pollution in 16 cities of Yunnan Plateau, the methods of COD, backward trajectory and potential source contribution function (PSCF) were used to analyze the O3 concentrations from 2015 to 2020 of all state-controlled environmental monitoring stations in 16 cities of Yunnan. The results show that the O3 concentrations in Yunnan gradually increased from 2015 to 2019, and the concentration in 2020 was the lowest due to the COVID-19 pandemic. The peak O3 concentration appears in spring. The daily change trend is a typical single peak shape, the lowest value appears around 8: 00, and the highest value is between 15:00 and 16:00. High concentrations of O3 are from the cities of Zhaotong and Kunming in northeastern Yunnan, while low concentrations of O3 mainly occur in the southwest and northwest border areas. Temperature and relative humidity are two meteorological parameters that have significant effect on O3 concentration. Temperature has the best correlation with O3 in winter, and relative humidity has a better correlation with O3 in autumn and winter than in spring and summer. Finally, source analysis of O3 showed that local ozone precursor emission sources and long-distance transmission from South and Southeast Asia constituted the major contributions of O3 in Yunnan.

Spillover effects of the United States economic slowdown induced by COVID-19 pandemic on energy, economy, and environment in other countries.

The United States has become the country hardest hit by the COVID-19 pandemic. This pandemic has not only led to the largest decline in economic output but also caused a sharp decline in carbon emissions and energy consumption in the United States after World War II. This study aims to evaluate how to spillover effects of the US economic slowdown caused by the COVID-19 pandemic on the 3E (Energy Economy Environment) in other countries. To this end, the international 3E for 2000 and 2014, and nine indicators based on network analysis to dynamically study the changes in the degree of 3E impact between countries. And then, we analyzed the impact of the epidemic on the 3E of various countries, with focusing on the interaction between the United States and other countries. The results show that the internal carbon emission density and internal energy consumption density of the United States declined during 2010-2014, whereas the internal carbon emission density and internal energy consumption density of developing countries increased. Next, changes in US carbon emissions induced by the epidemic have a more significant impact on Canada, China, Mexico, the European Union, and Russia. Finally, the internal and external carbon emission indexes of most countries have decreased, which indicates that most countries are affected by the carbon reduction and energy consumption caused by the pandemic in the US. This information provides a new perspective for assessing the impact of 3E between countries suffered from the COVID-19 Pandemic.