Qihang Chen

  Waste classification bins in the neighbourhood (Kong 2021) Since 2015, Hangzhou has had a specific regulation for domestic waste (Department of Hangzhou Law Administration 2015). This regulation details the scope of household waste, classification standards, collection and transportation methods, disposal options, controls, and penalties. However, based on my observations from 2017 to 2021, Hangzhou's performance on waste classification and recycling during this period could have been better. This was mainly reflected in residents' failure to classify waste. Most residents in Hangzhou needed a detailed understanding of the criteria for rubbish classification previously, thus requiring time and effort to organise waste before they could throw it away. In this case, some individuals will simply drop off their trash without classifying it to save time. Although there are penalties in the rules for this, only a few people were punished due to the lack of monitoring capacity. To m...

  Distribution of land surface temperature and surface urban heat island in the Hangzhou metropolitan area  ( Sheng, Lu & Huang 2015) Prolonged extreme heat is one of the leading extreme climate events that Hangzhou regularly suffers from in summer. The Hangzhou News (2022) reported that in August 2022, the temperature in Hangzhou reached 41.8 °C, a record high since 1951, and the high temperature remained for up to 26 days. Based on my personal experience of living and studying in Hangzhou, extreme heat for weeks will not only decrease the mobility of residents and businesses in the city, which will significantly depress tourism and entertainment, but also adversely affect the sustainability of the city: more air conditioners will be turned on by residents or companies; more private cars will be on the roads, and less public transport will be used because nobody wants to walk on the streets. The Hangzhou government has tried several approaches to cool the city, including ...

  Unusable paper straw (Feilu 2021) In Hangzhou, there has been a lot of controversy over an initiative to achieve the Sustainable Development Goals: replacing traditional plastic straws with paper straws. The amount of plastic straws used in China is quite large. According to China's National Bureau of Statistics (2020), nearly 46 billion plastic straws were produced in 2019, weighing around 30,000 tonnes. These straws can potentially cause significant environmental damage due to their small size and difficulty in degradation. Moreover, the production and burning process of plastic straws generates enormous amounts of pollution and carbon emissions. In contrast, paper straws are recyclable, naturally degradable and made from renewable materials. Using paper straws as an alternative to plastic straws then becomes a reasonable approach to achieving sustainable development goals. However, neither consumers nor food companies are satisfied with this initiative. Firstly, paper straws a...

  Rooftop garden of the Hangzhou International Expo Centre (Yadong 2016) The rooftop garden of the Hangzhou International Expo Centre, the main venue for the 11th G20 Summit in Hangzhou in 2016, was very impressive. Apart from discussing the garden's architectural style, its sustainability is also worthy of attention. Firstly, the greenery will reduce the exposure of the roof to direct sunlight or rain, thus extending the life of the building. Secondly, the vegetation on the top could serve to regulate the temperature. Compared to concrete roofs, green roofs have a significant cooling effect in summer (Kim, Lee, & Kang 2020). While in winter, the indoor temperature is instead increased due to the plants' respiratory effect and thermal insulation capacity. This can all contribute to energy savings. Therefore, some communities are considering building green rooftops on a large scale on their buildings. However, I do not think green rooftops will be popular in Hangzhou's r...

  Solar PV roof retrofit for office buildings (Hangzhou Urban and Rural Construction Committee 2021) By retrofitting existing buildings, Hangzhou has reached its goal of reducing carbon emissions. According to the Hangzhou Urban and Rural Construction Committee (2021), Hangzhou has reduced 38,722 tonnes of carbon emissions and saved energy equivalent to 14,893 tonnes of coal through retrofitting public buildings. The public facilities that have been upgraded include municipal government offices, universities, secondary schools and social houses. The transformation consisted of installing photovoltaic power on the roofs, upgrading lighting systems, modifying air conditioning systems, installing energy monitoring systems and more. The challenge remains how such retrofits can be extended to private and commercial buildings. For the non-public sector, undertaking energy efficiency retrofits is not always profitable. Firstly, the owner must pay the cost of retrofitting, and it may be im...

Manual concrete mixing (Tenglong 2015)  Week 8's lecture on 'Embodied carbon' in buildings brought a new perspective to my understanding of carbon emissions. In daily life, when discussing how to reduce greenhouse gas emissions, people are always more concerned with the efficiency of energy use on the road or inside the house rather than the carbon emissions generated by architecture before they are used. This is not unusual, as the public may be more interested in matters close to their real lives, and embodied carbon in buildings is an issue for developers to consider. However, as a student of urban planning and sustainability, and a former civil engineering student, I know this issue deserves attention and consideration. The impact of buildings on the environment is not limited to the encroachment on natural land and the energy consumed to maintain their function. The adverse effects on sustainability starts with the materials used in the construction of buildings. For i...