Road Traffic is the Bane of Our Existence
Written by Joanne Liu
Edited by Srinidhi Viswanathan
April 5, 2024
Edited by Srinidhi Viswanathan
April 5, 2024
Health and Wellness
Commonly associated with car accidents and heavy air pollution, motor vehicle traffic is a notorious safety hazard. In fact, in 2020, there were nearly 40,000 fatalities and over 2 million injuries on US roadways (Stewart, 2022). However, the dangers of traffic exposure are not just limited to commuters; local residents also share these risks.
Firstly, traffic exposure could have devastating consequences for bone health (Chen et al., 2015). To illustrate, proximity to traffic exposure was linked with lower bone mineral density (BMD) among Mexican American adults (Chen et al., 2015). Namely, the total body BMD of adults who lived within 500 meters of the nearest freeway was 0.02 g/cm2 lower than the total body BMD of adults who lived over 1,500 meters away from the nearest freeway (Chen et al., 2015). Thus, the adults who lived closer to freeways had a higher risk for osteoporosis, which increases the chance of fractures and permanent disability (Porter & Varacallo, 2018).
The association between proximity to traffic exposure and BMD has two possible explanations. Firstly, automotive exhaust contains polycyclic aromatic hydrocarbons, which have been shown to decrease bone mass and strength in rats (Chen et al., 2015; Lee et al., 2002). Additionally, living near traffic tends to discourage outdoor activity, thereby reducing sun exposure and vitamin D intake (Frank et al., 2003). Because vitamin D aids in the absorption of dietary calcium, which is stored in bones, people who live near traffic may be more susceptible to lower BMD (Chen et al., 2015; Møller & Loft, 2010).
Secondly, heavy traffic could harm cognitive and neurological health (Chen et al., 2017). For instance, in Ontario, Canada, individuals living closer to heavy traffic tended to have a higher risk for dementia than those living farther away (Chen et al., 2017). Notably, people who lived within 50 meters of a major road had a 7% higher risk of dementia than those who lived between 201 and 300 meters from a major road (Chen et al., 2017). Therefore, individuals who lived closer to major roads had a greater risk of functional impairment, which can result in complications that can lead to death (Volicer et al., 2001).
Two mechanisms underlie the correlation between distance to traffic exposure and the incidence of dementia. Firstly, traffic-related pollutants have been correlated with cognitive impairment (Power et al., 2011). In addition, high-traffic areas tend to be filled with impulse noise, which are single bursts of noise like hammering that are louder than background noise (Cui et al., 2012). In rats, exposure to impulse noise directly hindered spatial memory (Cui et al., 2012). Moreover, impulse noise exposure in high-traffic areas could fragment sleep, consequently obstructing optimal cognitive function (Baumgart et al., 2015).
Private transportation’s reigning popularity among commuters will only exacerbate road traffic, magnifying health concerns for both commuters and residents near major roadways. To address these issues, city officials will need to improve public infrastructure and transportation to mitigate traffic congestion and its harmful effects.
Works Cited
Baumgart, M., Snyder, H. M., Carrillo, M. C., Fazio, S., Kim, H., & Johns, H. (2015). Summary of the evidence on modifiable risk factors for cognitive decline and dementia: A population-based perspective. Alzheimer’s & Dementia, 11(6), 718-726. https://doi.org/10.1016/j.jalz.2015.05.016
Chen, H., Kwong, J. C., Copes, R., Tu, K., Villeneuve, P. J., von Donkelaar, A., Hystad, P., Martin, R. V., Murray, B. J., Jessiman, B., Wilton, A. S., Kopp, A., & Burnett, R. T. (2017). Living near major roads and the incidence of dementia, Parkinson's disease, and multiple sclerosis: a population-based cohort study. The Lancet, 389(10070), 18-24. https://doi.org/10.1016/S0140-6736(16)32399-6
Chen, Z., Salam, M. T., Karim, R., Toledo-Corral, C. M., Watanabe, R. M., Xiang, A. H., Buchanan, T. A., Habre, R., Bastain, T. M., Lurmann, F., Taher, M., Wilson, J. P., Trigo, E., & Gilliland, F. D. (2015). Living near a freeway is associated with lower bone mineral density among Mexican Americans. Osteoporosis International, 26, 1713-1721. https://doi.org/10.1007/s00198-015-3051-z
Cui, B., Wu, M., She, X., & Liu, H. (2012). Impulse noise exposure in rats causes cognitive deficits and changes in hippocampal neurotransmitter signaling and tau phosphorylation. Brain Research, 1427, 35-43. https://doi.org/10.1016/j.brainres.2011.08.035
Frank, L., Engelke, P., & Schmid, T. (2003). Health and community design: The impact of the built environment on physical activity. Island Press.
Lee, L. L., Lee, J. S. C., Waldman, S. D., Casper, R. F., & Grynpas, M. D. (2002). Polycyclic aromatic hydrocarbons present in cigarette smoke cause bone loss in an ovariectomized rat model. Bone, 30(6), 917-923. https://doi.org/10.1016/S8756-3282(02)00726-3
Møller, P., & Loft, S. (2010). Oxidative Damage to DNA and Lipids as Biomarkers of Exposure to Air Pollution. Environmental Health Perspectives, 118(8), 1126-1136. https://doi.org/10.1289/ehp.0901725
Porter, A. L., & Varacallo, M. (2018). Osteoporosis. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK441901/
Power, M. C., Weisskopf, M. G., Alexeeff, S. E., Coull, B. A., Spiro III, A., & Schwartz, J. (2011). Traffic-Related Air Pollution and Cognitive Function in a Cohort of Older Men. Environmental Health Perspectives, 119(5), 682-687. https://doi.org/10.1289/ehp.1002767
Stewart, T. (2022, March). Overview of motor vehicle crashes in 2020 (Report No. DOT HS 813266). National Highway Traffic Safety Administration.
Volicer, L., McKee, A., & Hewitt, S. (2001). Dementia. Neurologic Clinics, 19(4), 867-885. https://doi.org/10.1016/S0733-8619(05)70051-7
Firstly, traffic exposure could have devastating consequences for bone health (Chen et al., 2015). To illustrate, proximity to traffic exposure was linked with lower bone mineral density (BMD) among Mexican American adults (Chen et al., 2015). Namely, the total body BMD of adults who lived within 500 meters of the nearest freeway was 0.02 g/cm2 lower than the total body BMD of adults who lived over 1,500 meters away from the nearest freeway (Chen et al., 2015). Thus, the adults who lived closer to freeways had a higher risk for osteoporosis, which increases the chance of fractures and permanent disability (Porter & Varacallo, 2018).
The association between proximity to traffic exposure and BMD has two possible explanations. Firstly, automotive exhaust contains polycyclic aromatic hydrocarbons, which have been shown to decrease bone mass and strength in rats (Chen et al., 2015; Lee et al., 2002). Additionally, living near traffic tends to discourage outdoor activity, thereby reducing sun exposure and vitamin D intake (Frank et al., 2003). Because vitamin D aids in the absorption of dietary calcium, which is stored in bones, people who live near traffic may be more susceptible to lower BMD (Chen et al., 2015; Møller & Loft, 2010).
Secondly, heavy traffic could harm cognitive and neurological health (Chen et al., 2017). For instance, in Ontario, Canada, individuals living closer to heavy traffic tended to have a higher risk for dementia than those living farther away (Chen et al., 2017). Notably, people who lived within 50 meters of a major road had a 7% higher risk of dementia than those who lived between 201 and 300 meters from a major road (Chen et al., 2017). Therefore, individuals who lived closer to major roads had a greater risk of functional impairment, which can result in complications that can lead to death (Volicer et al., 2001).
Two mechanisms underlie the correlation between distance to traffic exposure and the incidence of dementia. Firstly, traffic-related pollutants have been correlated with cognitive impairment (Power et al., 2011). In addition, high-traffic areas tend to be filled with impulse noise, which are single bursts of noise like hammering that are louder than background noise (Cui et al., 2012). In rats, exposure to impulse noise directly hindered spatial memory (Cui et al., 2012). Moreover, impulse noise exposure in high-traffic areas could fragment sleep, consequently obstructing optimal cognitive function (Baumgart et al., 2015).
Private transportation’s reigning popularity among commuters will only exacerbate road traffic, magnifying health concerns for both commuters and residents near major roadways. To address these issues, city officials will need to improve public infrastructure and transportation to mitigate traffic congestion and its harmful effects.
Works Cited
Baumgart, M., Snyder, H. M., Carrillo, M. C., Fazio, S., Kim, H., & Johns, H. (2015). Summary of the evidence on modifiable risk factors for cognitive decline and dementia: A population-based perspective. Alzheimer’s & Dementia, 11(6), 718-726. https://doi.org/10.1016/j.jalz.2015.05.016
Chen, H., Kwong, J. C., Copes, R., Tu, K., Villeneuve, P. J., von Donkelaar, A., Hystad, P., Martin, R. V., Murray, B. J., Jessiman, B., Wilton, A. S., Kopp, A., & Burnett, R. T. (2017). Living near major roads and the incidence of dementia, Parkinson's disease, and multiple sclerosis: a population-based cohort study. The Lancet, 389(10070), 18-24. https://doi.org/10.1016/S0140-6736(16)32399-6
Chen, Z., Salam, M. T., Karim, R., Toledo-Corral, C. M., Watanabe, R. M., Xiang, A. H., Buchanan, T. A., Habre, R., Bastain, T. M., Lurmann, F., Taher, M., Wilson, J. P., Trigo, E., & Gilliland, F. D. (2015). Living near a freeway is associated with lower bone mineral density among Mexican Americans. Osteoporosis International, 26, 1713-1721. https://doi.org/10.1007/s00198-015-3051-z
Cui, B., Wu, M., She, X., & Liu, H. (2012). Impulse noise exposure in rats causes cognitive deficits and changes in hippocampal neurotransmitter signaling and tau phosphorylation. Brain Research, 1427, 35-43. https://doi.org/10.1016/j.brainres.2011.08.035
Frank, L., Engelke, P., & Schmid, T. (2003). Health and community design: The impact of the built environment on physical activity. Island Press.
Lee, L. L., Lee, J. S. C., Waldman, S. D., Casper, R. F., & Grynpas, M. D. (2002). Polycyclic aromatic hydrocarbons present in cigarette smoke cause bone loss in an ovariectomized rat model. Bone, 30(6), 917-923. https://doi.org/10.1016/S8756-3282(02)00726-3
Møller, P., & Loft, S. (2010). Oxidative Damage to DNA and Lipids as Biomarkers of Exposure to Air Pollution. Environmental Health Perspectives, 118(8), 1126-1136. https://doi.org/10.1289/ehp.0901725
Porter, A. L., & Varacallo, M. (2018). Osteoporosis. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK441901/
Power, M. C., Weisskopf, M. G., Alexeeff, S. E., Coull, B. A., Spiro III, A., & Schwartz, J. (2011). Traffic-Related Air Pollution and Cognitive Function in a Cohort of Older Men. Environmental Health Perspectives, 119(5), 682-687. https://doi.org/10.1289/ehp.1002767
Stewart, T. (2022, March). Overview of motor vehicle crashes in 2020 (Report No. DOT HS 813266). National Highway Traffic Safety Administration.
Volicer, L., McKee, A., & Hewitt, S. (2001). Dementia. Neurologic Clinics, 19(4), 867-885. https://doi.org/10.1016/S0733-8619(05)70051-7
Image Source: "Parked Gray Car" by Kaique Rocha licensed under Pexels License