When the air outside is polluted, office workers are more likely to order food delivery than go out for lunch, which in turn increases plastic waste from food packaging, according to a study by researchers from the National University of Singapore (NUS).
The new study focused on China, which is among the world’s largest users of online food delivery platforms, with 350 million registered users. An estimated 65 million meal containers are discarded each day across China, with office workers contributing over one-half of demand, according to a statement.
The study surveyed the lunch choices of 251 office workers repeatedly over time (each worker for 11 workdays) in three often smog-filled Chinese cities – Beijing, Shenyang and Shijiazhuang – between January and June 2018.
To complement the office-worker survey, the researchers also accessed the 2016 Beijing order book of an online food delivery platform, which broadly represented all market segments served by the food delivery industry—collecting observational data on 3.5 million food delivery orders from about 350,000 users.
Data from the survey and order book were then compared with PM2.5 measurements (fine particles less than 2.5 micrometers in diameter) during lunchtime periods from the air-monitoring network in all three cities.
It was observed that PM2.5 levels during these periods were often well above the 24-hour US National Ambient Air Quality Standard of 35 μg/m³, making pollution highly visible. The researchers were careful to control for confounding factors such as economic activity.
Both data sources indicated a strong link between PM2.5 (haze) pollution and food delivery consumption. Correcting for weather and seasonal influences, the firm’s order book revealed that a 100 μg/m³ increase in PM2.5 raised food delivery consumption by 7.2 percent. The impact of a 100 μg/m³ PM2.5 shift on office workers’ propensity to order delivery was six times larger, at 43 percent.
The researchers estimated that a 100 μg/m³ PM2.5 increase raised a meal’s disposable plastic use by 10 grams on average – equivalent to about one-third the mass of a plastic container.
Based on the order book, the researchers also estimated that on a given day, if all of China were exposed to a 100 μg/m³ PM2.5 increase in dose as is routinely observed in Beijing, 2.5 million more meals would be delivered, requiring an additional 2.5 million plastic bags and 2.5 million plastic containers.
Image credit: Lei Han, flickr/Creative Commons