When and where to exercise: An assessment of personal exposure to urban tropical ambient airborne pollutants in Singapore

Xin Yin; Bao Ngoc Thai; Yue Qian Tan; Santo V Salinas; Liya E Yu; Wei Jie Seow

doi:10.1016/j.scitotenv.2023.167086

When and where to exercise: An assessment of personal exposure to urban tropical ambient airborne pollutants in Singapore

Sci Total Environ. 2024 Jan 1:906:167086. doi: 10.1016/j.scitotenv.2023.167086. Epub 2023 Sep 15.

Authors

Xin Yin¹, Bao Ngoc Thai², Yue Qian Tan¹, Santo V Salinas³, Liya E Yu⁴, Wei Jie Seow⁵

Affiliations

¹ Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore.
² NUS Environmental Research Institute (NERI), National University of Singapore, Singapore.
³ Center for Remote Imaging, Sensing and Processing (CRISP), National University of Singapore, Singapore.
⁴ NUS Environmental Research Institute (NERI), National University of Singapore, Singapore; Department of Civil and Environmental Engineering, National University of Singapore, Singapore.
⁵ Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore. Electronic address: ephswj@nus.edu.sg.

PMID: 37716686
DOI: 10.1016/j.scitotenv.2023.167086

Abstract

Background: Physical activity is associated with health benefits and has been shown to reduce mortality risk. However, exposure to high levels of ambient fine particulate matter (PM_2.5) during exercise can potentially reduce the health benefits of physical activity. This study aims to assess and compare the PM_2.5 concentrations of different exercise venues in Singapore by their location attributes and time of day.

Methods: Personal PM_2.5 exposures (μg/m³) at 24 common outdoor exercise venues in Singapore over 49 sampling days were collected using real-time personal sensors from September 2017 to January 2020. Wilcoxon rank-sum test and Kruskal-Wallis test were used to compare PM_2.5 concentrations between different timings (peak (0700-0900; 1800-2000) vs. non-peak (0600-0700; 0900-1800; 2000-2300); weekend vs. weekday), and location attributes (near major roads (<50 m) vs. away from major roads (≥50 m)). Multivariable linear regression models were used to assess the associations between location attributes, timings and ambient PM_2.5 with personal PM_2.5 concentration, adjusting for potential confounders.

Results: Compared with peak hours, exercising during non-peak hours was associated with a significantly lower PM_2.5 exposure (median, 17.8 μg/m³ during peak vs. 14.5 μg/m³ during non-peak; P = 0.006). Exercise venues away from major roads have significantly lower PM_2.5 concentrations as compared to those located next to major roads (median, 14.4 μg/m³ away from major roads vs. 18.5 μg/m³ next to major roads; P < 0.001). Individuals who exercised in parks experienced the highest PM_2.5 exposure (median, 55.0 μg/m³) levels in the afternoon during 1400-1500. Furthermore, ambient PM_2.5 concentration was significantly and positively associated with personal PM_2.5 exposure (β = 0.85, P < 0.001).

Conclusions: Our findings suggest that exercising outdoors in the urban environment exposes individuals to differential levels of PM_2.5 at different times of the day. Further research should investigate a wider variety of outdoor exercise venues, explore different types of air pollutants, and consider the varying activity patterns of individuals.

Keywords: Exercise location; Major roads; PM(2.5) exposure; Park; Peak hours.

MeSH terms

Air Pollutants* / analysis
Air Pollution* / analysis
Environmental Exposure / analysis
Environmental Monitoring
Environmental Pollutants*
Humans
Particulate Matter / analysis
Singapore

Substances

Environmental Pollutants
Air Pollutants
Particulate Matter