How people travel daily from one place to another has significant consequences on their health and the health of their community. Most people travel by themselves in cars and trucks, and these vehicles are major contributors of environmental pollutants that cause both short- and long-term health impacts. Passenger vehicles are also significant emitters of greenhouse gases, which contribute to climate change. On the other hand, active modes of transportation such as walking, cycling, or using public transit can lessen harmful emissions to the environment and improve the health of commuters through increased physical activity.

Passenger vehicle emissions include particulate matter, nitrogen oxides, and volatile organic compounds,[1] together described as transport-related air pollution (TRAP). The components of TRAP have clearly established health effects.[2] These include upper respiratory tract irritation, exacerbation of chronic respiratory illness, increased risk of cardiovascular disease, and impaired lung and nervous system development in children, as well as neurodegenerative diseases, and premature mortality in adults.[3,4] A clear gradient exists for these pollutants, with the highest levels occurring near major roadways.

In addition, an inactive lifestyle contributes to many chronic diseases, and commuting by car is specifically associated with obesity, poor sleep, stress, and poor self-reported health.[5,6]

Finally, the negative health effects of climate change are also serious. The transportation sector is second behind the oil and gas industry as a source of climate-changing greenhouse gas in Canada (26% and 24% of all greenhouse gas emissions, respectively). Passenger vehicles are the largest sources of emissions within the transportation sector.[7]

An alternative to the passenger vehicle is active transport—going to places by walking, biking, or taking public transit. At the individual level, trials have shown that active commuting decreases BMI, improves cardiovascular health, and reduces the incidence of diabetes.[8,9] At the community level, active transport (in most cases) emits fewer pollutants and greenhouse gases per passenger-kilometre traveled and is a key component to mitigating climate change.

Physicians already recommend physical exercise to treat and prevent chronic illness, and this can prompt a discussion about commuting. Because of patients’ busy schedules, active commuting, whether taking the bus, walking, or biking, may be a more realistic goal than a dedicated exercise regimen. Some patients may also be motivated by being made aware that active commuting benefits the climate. Moreover, physicians can lead by example by using active transportation themselves.

Unfortunately, in many areas of BC active transportation may not always be practical. Some communities have limited public transit options and insufficient pedestrian- and cycling-friendly infrastructure. Research suggests that the negative health impacts of unhealthy built environments are particularly felt by vulnerable populations such as children, the elderly, and low-income residents.[10] As medical experts, physicians can play an influential role in advocating for transportation and planning policies that promote active transportation and improve the health of their patients and community.
—David McVea, MD
—Emily Peterson, MPH
—James Lu, MD
Environmental Health Committee

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This article is the opinion of the Environmental Health Committee, a subcommittee of Doctors of BC’s Council on Health Promotion, and is not necessarily the opinion of Doctors of BC. This article has not been peer reviewed by the BCMJ Editorial Board.

References

1.    Environment and Climate Change Canada. Cars, trucks, vans and sport utility vehicles (SUVs). Accessed 15 August 2017. www.ec.gc.ca/air/default.asp?lang=En&n=EC8E75D0-1 [11].
2.    Kim KH, Kumar P, Szulejko JE, et al. Toward a better understanding of the impact of mass transit air pollutants on human health. Chemosphere 2017;174:268-279.
3.    Xu X, Ha SU, Basnet R. A review of epidemiological research on adverse neurological effects of exposure to ambient air pollution. Front Public Health 2016;4:157.
4.    Goldizen FC, Sly PD, Knibbs LD. Respiratory effects of air pollution on children. Pediatr Pulmonol 2016;51:94-108.
5.    Booth FW, Roberts CK, Laye MJ. Lack of exercise is a major cause of chronic diseases. Compr Physiol 2012;2:1143-1211.
6.    King DM, Jacobson SH. What is driving obesity? A review on the connections between obesity and motorized transportation. Curr Obes Rep 2017;6:3-9.
7.    Environment and Climate Change Canada. Greenhouse gas emissions by Canadian economic sector. Accessed 15 August 2017. www.ec.gc.ca/indicateurs-indicators/default.asp?lang=en&n=F60DB708-1 [12].
8.    Panter J, Ogilvie D. Cycling and diabetes prevention: Practice-based evidence for public health action. PLoS Med 2016;13:e1002077.
9.    Flint E, Webb E, Cummins S. Change in commute mode and body-mass index: Prospective, longitudinal evidence from UK Biobank. Lancet Public Health 2016;1:e46-e55.
10.   Canadian Medical Association. Policy on the built environment and health. 7 December 2013. Accessed 3 October 2017. http://policybase.cma.ca/dbtw-wpd/Policypdf/PD14-05.pdf [13].