The effect of hosting international mega-events on urban haze pollution in China:Based on a quasi-natural experiment

With the rapid economic and social development of China,more and more Chinese cities are hosting important international events.However,the long-term effects of hosting international events on urban haze pollution are rarely discussed in existing literature.Based on the quasi-natural experiment of China hosting the G20 Hangzhou Summit in 2016,this paper applies the synthetic control method (SCM) for the first time to evaluate the impact of the G20 Hangzhou Summit on urban haze pollution in China.Compared with the traditional method,SCM measures the long-term impact of hosting the G20 Summit on haze pollution more scientifically.The results show that hosting the G20 Summit did improve the haze pollution in Hangzhou.The effectiveness and robustness of the above conclusions are objectively confirmed by multi-dimensional tests such as placebo test,permutation test,iterative test and difference-in-differences model.Further mechanism analysis shows that foreign direct investment and technological innovation are important channels for the G20 Summit to curb haze pollution in Hangzhou.At the same time,this paper employs a series of methods to systematically evaluate the impact of the G20 Hangzhou Summit on haze pollution in both time and space dimensions.This paper provides a credible basis and empirical support for the impact of international mega-events on air pollution in China.

G20 Hangzhou Summit:New Turning Point of Global Economic Governance

The G20 Hangzhou Summit has come to a conclusion.With the G20 state leaders as well as the leaders of seven major international agencies and eight guest states gathering together,having enthusiastic and effective in-depth discussions and reaching extensive consensus,the one-and-half-day meeting has been a complete success.The Summit

Characteristics and source attribution of PM2.5 during 2016 G20 Summit in Hangzhou: Efficacy of radical measures to reduce source emissions

A field campaign was conducted to study the PM2.5 and atmospheric gases and aerosol’s components to evaluate the efficacy of radical measures implemented by the Chinese government to improve air quality during the 2016 G20 Summit in Hangzhou China.The lower level of PM2.5(32.48±11.03μg/m3)observed during the control period compared to precontrol and post-control periods showed that PM2.5 was alleviated by control policies.Based on the mass concentrations of particulate components,the emissions of PM2.5 from local sources including fossil fuel,coal combustion,industry and construction were effectively reduced,but non-exhaust emission was not reduced as effectively as expected.The accumulation of SNA(SO42-,NO3-,NH4+)was observed during the control period,due to the favourable synoptic weather conditions for photochemical reactions and heterogeneous hydrolysis.Because of transboundary transport during the control period,air masses from remote areas contributed significantly to local PM2.5.Although,secondary organic carbon(OCsec)exhibited more sensitivity than primary organic carbon(OCpri)to control measures,and the increased nitrogen oxidation ratio(NOR)implied the regional transport of aged sec-ondary aerosols to the study area.Overall,the results from various approaches revealed that local pollution sources were kept under control,indicating that the implementation of mitigation measures were helpful in improving the air quality of Hangzhou during G20 summit.To reduce ambient levels of PM2.5 further in Hangzhou,regional control policies may have to be taken so as to reduce the impact of long-range transport of air masses from inland China.

G20 Hangzhou Summit Points the Way for the World Economy

The 2016 G20 Summit was successfully held in Hangzhou,China on Sept 4 and 5.This fruitful meeting has set the course for the world in such respects as economic growth,response to global challenges and global governance system reform.The world economy again