A psychophysical measurement on subjective well-being and air pollution

Although the physical effects of air pollution on humans are well documented, there may be even greater impacts on the emotional state and health. Surveys have traditionally been used to explore the impact of air pollution on people’s subjective well-being (SWB). However, the survey techniques usually take long periods to properly match the air pollution characteristics from monitoring stations to each respondent’s SWB at both disaggregated spatial and temporal levels. Here, we used air pollution data to simulate fixed-scene images and psychophysical process to examine the impact from only air pollution on SWB. Findings suggest that under the atmospheric conditions in Beijing, negative emotions occur when PM2.5 (particulate matter with a diameter less than 2.5 µm) increases to approximately 150 AQI (air quality index). The British observers have a stronger negative response under severe air pollution compared with Chinese observers. People from different social groups appear to have different sensitivities to SWB when air quality index exceeds approximately 200 AQI.


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Study description
This research focus on the effect of air pollution on people's emotions.We simulate a set of air pollution images of Beijing by building a model to explain the relationship between colour information from colour-managed fixed-scene digital images and collected hourly air pollution data and weather/climate data in Beijing. Then, in laboratory-based psychophysical visual experiments, observers from the UK and China will be asked to judge simulated image samples exhibiting various air pollution levels in terms of their SWB to quantify positive and negative emotions. Thus, the personal SWB data and air pollution data with fixed locations/scenes, times, weather and climate conditions could be perfectly matched.

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Students and employees of University in the UK (e.g. UEA) and Peking University Sampling strategy UK participants was recruited through a process of advertisement. We advertised participants via email and poster in common area. Potential participants responded to the advertisement via email and, following a short email discussion, will be screened for colour blindness. Participants who pass the colour-blindness test will be invited to take part in the study. The potential participants could refuse to take part in this experiment at any time.
Chinese participants were recruited through a similar process, such as advertisement in the College of Urban Environment, Peking University. There are over 900 students and 200 staffs working for the college. We put posters in common areas and email to students and staffs. Potential participants responded to the advertisement via email and, following a short email discussion, will be screened for colour blindness in an academic visitor office. Participants who pass the colour-blindness test will be invited to take part in the study. The potential participants could refuse to take part in this experiment at any time.

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Categorical judgement was used to collect data during both experiments. In total, 18 images of different air quality conditions were examined, and 6 emotions were evaluated. During the experiment, one image (24 cm × 16 cm) was presented at a time in the centre of the display (see Figure S4), and the image was viewed from approximately 80 cm. The observers were presented with 7 buttons underneath each image that they could click to select one of the 6 emotions. Then, the air quality image disappeared and was replaced by a new image. This process continued until all 6 emotions were judged. Before the experiment started, some basic information on the observers was collected, including gender, age, and attitudes regarding the necessity to wear a mask and the impact of air pollution on health, the average number of hours spent outside and whether they had children. Then, the observers were asked to imagine that in the next 5 to 10 years, they would live for approximately 2 months in the air quality conditions shown on the display. All answers were recorded automatically in an electronic file.

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The experiment was implemented in January 2019.

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No data was excluded Non-participation None Randomization Two large groups were assigned based on one experiment was carried out in China, the other one in the UK.

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