Archives par mot-clé : air pollution

Car free days and sustainable physical activity.

A systematic review examined the health benefits associated with car free events and health outcomes (e.g., air pollution, physical activity, noise) (1). Among 23 included papers, one collected device-measured physical activity data (2), two estimated the physical activity levels of population with surveys (3,4).

Ciclovia is a weekly event created in Bogota, Colombia. Every Sunday, about 121 kilometers (70 miles) of roads are closed to motorized traffic. I can easily understand this impact with the following video.

The Ciclovia initiative was associated with a moderate and vigorous physical activity increase of 6 minutes and a sedentary behaviour reduction of 19 minutes among children participating (2). Most Ciclovia participants (adults) reported had low-to-middle educational attainment, and did not own cars. This event was associated with a possible 13% rate of people attaining international guidelines.

Another initiative was examined. Brownville, Texas, USA closes 3 miles (ca. 5 km) of town center streets (4 to 6 times per year). During this car-free event, 17.3% of attendees met weekly recommended physical activity levels.

This low number of included paper is surprising. Authors included papers or reports from grey literature but (maybe) they did not include the papers published in Spanish. Another explanation may be the lack of resources to measure physical activity behaviors (5). For instance, 17 countries of Latin America had a Ciclovia program between 1974 and 2016 (6). Only two articles (in English) was found on this initiative.

Two US studies (not included in this review) investigated the physical activity related behaviours during a Ciclovia program carried out in San Diego and Los Angeles, respectively.

Direct observations were performed in San Diego. It indicated that 85% of attendees were bicycling and 15% were walking. Study participants reported an average of 144 minutes of physical activity during the Ciclovia event. 39% of participated met the physical activity recommendations. Moreover, no significant differences were found between gender, ethnicity, income (7).

The Clovia program was named CicLAvia in Los Angeles (8). This initiative was initiated in 2010, and repeated 4 times per year for 6 miles (ca. 10 km). Physical activity data were collected with video cameras (at 1-mile intervals along the CicLAvia route), GPS “wore” by volunteers following the participants, and questionnaires. The GPS data showed an average traveling distance of 8.68 miles. At a speed of 6 miles/h, it would take 1.45 h to traverse this distance. Authors estimated that a total of 163,000 to 245,000 MET hours was expended by cyclists and a total of 13,500 to 18,000 MET hours was expended by pedestrians. 50% of respondents met the national guidelines of 150 min per week. Nearly 27% of participants said they if they had not been at CicLAvia, they would have stayed home while another 18% said they would have been sedentary.

In health and climate change perspective (9), these events may be a useful temporary solution to:

  • decrease the air/noise pollution exposition,
  • increase the physical activity level of local population,
  • offer a safe experimentation of active transport for all,
  • experiment a city with lower car traffic.
  • 1. Glazener A, Wylie J, van Waas W, Khreis H. The Impacts of Car-Free Days and Events on the Environment and Human Health. Curr Envir Health Rpt. 1 juin 2022;9(2):165‑82.
  • 2. Triana CA, Sarmiento OL, Bravo-Balado A, González SA, Bolívar MA, Lemoine P, et al. Active streets for children: The case of the Bogotá Ciclovía. PLOS ONE. 15 mai 2019;14(5):e0207791.
  • 3. Salazar-Collier CL, Reininger B, Gowen R, Rodriguez A, Wilkinson A. Evaluation of Event Physical Activity Engagement at an Open Streets Initiative Within a Texas-Mexico Border Town. J Phys Act Health. 1 août 2018;15(8):605‑12.
  • 4. Torres A, Sarmiento OL, Stauber C, Zarama R. The Ciclovia and Cicloruta programs: promising interventions to promote physical activity and social capital in Bogotá, Colombia. Am J Public Health. févr 2013;103(2):e23-30.
  • 5. O’Donovan G. Accuracy and inequalities in physical activity research. The Lancet Global Health. 1 févr 2019;7(2):e186.
  • 6. Sarmiento OL, Díaz del Castillo A, Triana CA, Acevedo MJ, Gonzalez SA, Pratt M. Reclaiming the streets for people: Insights from Ciclovías Recreativas in Latin America. Preventive Medicine. 1 oct 2017;103:S34‑40.
  • 7. Engelberg JK, Carlson JA, Black ML, Ryan S, Sallis JF. Ciclovía participation and impacts in San Diego, CA: The first CicloSDias. Preventive Medicine. déc 2014;69:S66‑73.
  • 8. Cohen D, Han B, Derose KP, Williamson S, Paley A, Batteate C. CicLAvia: Evaluation of participation, physical activity and cost of an open streets event in Los Angeles. Preventive Medicine. 1 sept 2016;90:26‑33.
  • 9. Bernard P, Chevance G, Kingsbury C, Baillot A, Romain AJ, Molinier V, et al. Climate Change, Physical Activity and Sport: A Systematic Review. Sports Med. 1 mai 2021;51(5):1041‑59.

Gendered inequalities, health and climate change

In climate change perspectives, three inequalities have been well-documented: inequalities between (1) and within countries (2), and inequalities between generations (3). However, the gendered inequalities are and will be exacerbated by climate change consequences (4). An open-access chapter presents the most important issues of this question (4). Authors add a health perspective combined with climate change gendered inequalities.

A set of key points:

  • Deaths related to natural disasters are higher among women. Their motor skills are generally lower than men (e.g., running, swimming, climbing). Also, they have a poor access to climate-related information.
  • Women may be more “biologically vulnerable” during heat waves. High temperatures also are associated with complications in pregnancy and poor neonatal outcomes.
  • Women are more exposed to indoor pollution (from fuel-wood stoves) and have higher burden to outdoor air pollution.
  • Women are the worst affected by food insecurity because they are (most of time) responsible for cooking, feeding caring…. and they eat less.
  • During dry seasons, women spend time and energy to collect water. It increases their risk of heat illness

You can find an interactive map displaying 130 studies that investigate how men and women are affected by climate change here .


  • 1. Guivarch C, Taconet N. Global inequalities and climate change. In: The Routledge Handbook of the Political Economy of the Environment. Routledge; 2021.
  • 2. United Nations Environment Programme. The emissions gap report 2020. 2020.
  • 3. Thiery W, Lange S, Rogelj J, Schleussner C-F, Gudmundsson L, Seneviratne SI, et al. Intergenerational inequities in exposure to climate extremes. Science [Internet]. 8 oct 2021 [cité 27 déc 2021]; Disponible sur:
  • 4. Kommu V, Alexander D, Lingam L. Gendered vulnerabilities and health inequities. In: Climate Change and the Health Sector [Internet]. 1re éd. London: Routledge India; 2021. p. 90‑7.

Complex associations between air pollution, insomnia symptoms and physical activity

In a preprint co-authored with G. Chevance et al. (1), we examined the associations between climate change consequences and health behaviors. We identified a set of (bi)directional associations between natural hazards, rising sea level, greenhouse gas emission, temperature increase and the following behaviors : alcohol consumption, cigarette smoking, water consumption, preventive behaviors, sleep, food related behaviors and physical activity (PA) domains. We synthesized these associations with this figure.

This system map offers a “meta” and simplified perspective of previous studied associations. However, we did not include the potential associations between health behaviors. Indeed, these associations are not well identified and may be different in function of the time scale (i.e., daily associations vs long term association), study participant characteristics and assessment tools (see e.g., see the following reviews for PA sleep associations at short and long term (2,3)).
A recent cross-sectional study investigated the associations of long-term exposure to ambient air pollution with insomnia symptoms in a large Chinese sample. Furthermore, the authors examined whether PA domains had a potential “buffering effect”.
In the perspective of our review, it’s particularly relevant because we could improve the subsection about sleep, PA domains, and air pollution (4). Also, China is one of the most polluted countries in the world.

Strengths of this study:

  • -residents >3 years in their current residence
  • relative good measure of insomnia symptoms
  • good control of indoor air pollution and environmental factors (e.g., temperature)

I synthesized Xu et al. findings with the following slides (4). A buffering effect of physical activity was found for leisure PA and moderate PA “doses”. High levels of total and occupational PA accentuated the air pollution – insomnia association. In brief, the potential positive role of PA varied in term of domain, dose and air pollution measures.



This study is a good illustration of health behaviors associations complexity. In a climate change perspective (i.e., higher level of air pollution in cities around the world in next decades), physical activity promotion and insomnia prevention/treatment strategies should be revised.

  • 1. Chevance G, Fresán U, Hekler E, Edmondson D, Lloyd S j, Ballester J, et al. Thinking health-related behaviors in a climate change context: A narrative review [Internet]. OSF Preprints; 2021 [cited 2021 May 19]. Available from:
  • 2. Kredlow MA, Capozzoli MC, Hearon BA, Calkins AW, Otto MW. The effects of physical activity on sleep: a meta-analytic review. J Behav Med. 2015 Jun;38(3):427–49.
  • 3. Atoui S, Chevance G, Romain A-J, Kingsbury C, Lachance J-P, Bernard P. Daily associations between sleep and physical activity: A systematic review and meta-analysis. Sleep Medicine Reviews. 2021 Jun;57:101426.
  • 4. Xu J, Zhou J, Luo P, Mao D, Xu W, Nima Q, et al. Associations of long-term exposure to ambient air pollution and physical activity with insomnia in Chinese adults. Science of The Total Environment. 2021 Oct;792:148197.