Transactions in Urban Data,Science,and Technology

The average salt intake of Chinese residents far exceeds the recommended standard. As food delivery becomes increasingly popular among the Chinese public, salt reduction for takeaways is important to reduce salt intake of Chinese residents. However, studies related to salt reduction of takeaways are still very few; especially, no study has explored consumers’ attitudes towards salt level in takeaway meals. The purpose of the study was to objectively measure consumers’ request for reduced-salt options when ordering meals online, from real takeaway orders. Consumer messages from 718 restaurants on a meal delivery app called ELEME in China were collected between July and December 2020. Reduced-salt messages from all consumer messages placed by consumers when ordering meals were extracted to determine the extent of customized salt reduction requests and to analyze the content of those requests. Feature words from messages identified through AI machine learning (Term Frequency and Term Frequency-Inverse Document Frequency method) were extracted and analyzed. Out of 25,982 consumer messages, 10,549 (40.6%) were reduced-salt messages. Consumers, in general, had the demand to customize dishes with less salt – “less salt” was the most frequently mentioned word for taste preference. Populations with special health and nutritional needs may have a higher demand for reduced-salt meals according to these messages. The study showed definite patterns of demand in a sizable minority of orders and identified the feature words and concepts that could feed into future efforts to create an effective choice architecture in online meal delivery platforms.

With China’s remarkable progress in smart city and Information and Communication Technologies (ICTs), novel technologies have gradually permeated through research on micro-scale environmental exposure research. Consequently, the research has undergone a series of transitions and seen new progress. This article reviews and summarizes three transitions of micro-scale environmental monitoring, exposure, and individual response in Chinese literature:(1) the micro-scale transition in individual-level environment monitoring, including technologies such as mobile particulate monitors, portable physiological monitors, and virtual reality for micro-scale environmental monitoring; (2) the real-time transition towards individual environmental exposure measurement; (3) the individual response to environmental exposure. In this context, environmental exposure research intersects with many disciplines and contributes practical value in the fields of micro-spatial governance, healthy spatiotemporal behavior, and targeted pollution prevention.

During COVID-19, people needed to travel and meet as a group physically to gain benefits such as overcoming loneliness. Using multiday continuous smartcard data, we can identify intentional travel groups (ITGs) in cities. Using the 2020 smartcard data of the Hong Kong metro system, we first construct a dataset of probable ITG trips (PIGTs) where two riders swiped in and out at the same stations within one minute during weekends—we choose weekends because there are fewer co-presenting metro commuters entering and/or exiting the same station. Assuming that ITGs would have more PIGTs and smaller exit time difference than those co-presenting by coincidence, we then identified ITGs as those with at least four PIGTs in a month. To see whether and how the pandemic impacted ITGs, we geo-visualize the quantity of the identified ITGs by metro station and between metro stations on three different Sundays before and during the pandemic. The results indicate that ITGs’ distribution by metro station and between metro stations changed notably after the outbreak of COVID-19.

Trip chains, consisting of multiple interconnected trips serving different functions and/or purposes, occur commonly among urban residents. Non-metro trips (NMTs) between a pair of metro stations as parts of trip chains predominantly carried by metro systems have received little attention in the existing scholarship and practice. They contribute, however, to “Life between Stations” (LbS)—various activities engaged in by metro riders and other urban residents around or between stations. LbS affects residents’ level of satisfaction for trip chains, sense of belonging, and even overall quality of life. But for a given city, where do those NMTs occur more frequently and how long are the durations? Using the 12-weekend metro smartcard swipe records in 2019 in Hong Kong, we defined, quantified, and visualized NMTs and associated metro station pairs in a real-world setting. We found that (a) the NMTs and LbS occurred between as many as 179 metro station pairs, involving 84 out of the 95 local metro stations, (b) the NMTs and LbS varied across the station pairs and/or metro lines, and (c) commercial and densely populated areas saw more than elsewhere. These findings shed light on efforts undertaken to better understand and improve LbS of metro riders.