Natural ventilation potential for residential buildings in a densely built-up and highly polluted environment. A case study

The application of Natural Ventilation (NV) as a measure to improve comfort conditions in transition and summer periods has been a topic of research on the spotlight for years. However, there is a lack of knowledge about how the combined effect of a dense urban layout with high pollutant concentrations may affect its potential. This paper addresses this gap by running detailed thermal simulations for a typical apartment flat located in the Yuzhong district of Chongqing city (China) using a holistic approach that makes use of: i) wind pressure coefficients on building facades from urban-scale CFD simulations, ii) hourly measured values of PM2.5 concentrations and weather variables and iii) indoor environment measurements for validation purposes. Scenario analysis revealed the average amount of air change rates achievable in a year varies from 8 to 15 ACH according to the windows orientation. These figures drop down to around 2 ACH when taking into account reduced windows opening time when outdoor PM2.5 concentrations are too high. The resulting natural ventilation potential of the case study decreases from 4234 h when outdoor pollution is neglected to 2707 and 529 h when considering the exposure thresholds set by the Chinese government and the WHO respectively

Elephant poaching and the ivory trade: The impact of demand reduction and enforcement efforts by China from 2005 – 2017

African elephants are iconic species threatened by poaching and China was considered as one of the main destinations for illegally sourced ivory. In this article we combine two surveys of ivory carving enterprises with other data sets, including Chinese government seizure statistics, market prices for illegal ivory and substitute goods, to understand the impact of enforcement and demand reduction measures on ivory prices and poaching. Our analysis indicates the strong enforcement measures to combat ivory smuggling temporarily suppressed the tendency of illegal trade while stimulating a steep rise in illegal ivory prices thereafter. Peaking in 2012–2013, prices thereafter fell due to government measures to reduce demand under China's ‘Ecological Civilization’ programme and the announcement of ‘The Eight-point Regulation of the Centre’. Our survey suggests that most Chinese carving enterprises were intending to close or to diversify their business activities away from ivory carving as a result of the total ban on domestic ivory trading by 31st December 2017. And China had banned domestic ivory trade for over half a year and all ivory carving enterprises closed their ivory business activities since this domestic ban. In order to prevent ivory demand in other countries that may undermine Chinese efforts, we argue that other countries now also need to adopt multifaceted actions to curtail their domestic ivory trade