Cycling, air pollution exposure & health An overview of research findings

Transcription

1 Cycling, air pollution exposure & health An overview of research findings Michael Brauer, Christie Cole The University of British Columbia School of Population and Public Health VeloCity 2012 June 27, 2012 Vancouver

2 cycling in cities cyclingincities.spph.ubc.ca The cycling near market survey Adults Metro Vancouver 2,149 completed telephone interview 1,402 completed web/mail questionnaire regular cyclists: cycle at least weekly 2.4% of population, ~40,000 adults frequent cyclists: cycle at least monthly 9.9% of population, ~160,000 adults occasional cyclists: cycle at least yearly 12.7% of population, ~200,000 adults potential cyclists: cycle at least weekly 6.2% of population, ~100,000 adults other adults, 68.8% of population ~1,100,000 Winters M, Davidson G, Kao D, Teschke K. Motivators and deterrents of bicycling: comparing influences on decisions to ride. Transportation DOI /s y

3 cycling in cities most positive influences on decisions to cycle (top 15 of 73) LIKELIHOOD OF CYCLING 1= much m ore likely 0= no influence -1 = much less likely all participants regular cycl ists occasional cycl ists potential cycl ists The route is awa y from traffic noise & air pol lution The route has bicycle paths separated from traffic for the entire distance The route has beautiful scenery Cycling to the destination takes less time than traveling by other modes The route is flat The distance to my destination is less than 5 km Secure indoor bike storage I can take my bike on the SkyTrain at any time A 2-way off-street bike pat h has a reflective centre line for night & poor weather cycling I can make the trip in daylight hours Covered bike racks, to protect from rain Informat ion about cycling routes to the destination is available The route has bike signage, pave ment markings & bike activated signals on residential streets The bus has racks that carry bike s A web-based trip-planning tool is available Winters M, Davidson G, Kao D, Teschke K. Motivators and deterrents of bicycling: comparing influences on decisions to ride. Transportation DOI /s y

4 Air pollution and health Air pollution individual risk is small but large exposed population = large population impact no threshold On days with worse air quality, more people die In more polluted cities, people die earlier than in less polluted cities and, in the most polluted areas of cities, there is an increased risk of dying Brauer et al Crouse et al

5 Karner et al. (2010) Environ. Sci. Technol. 44, 5334 Pollution gradients

6 Henderson et al. 2007; Brauer et al Traffic proximity N Legend Freeways Major Roads Annual NO (ppb) Traffic influence zones 32% of Canadian population 36% of primary schools in large Canadian cities

7 Methods Large databases searched (PubMED, Web Of Science, EMBASE, Google Scholar, etc.) Search initiated using terms from known relevant articles Multiple key words searched using AND statements ex. bicycl* AND physical activity AND risk; distinct search terms used to address specific topics Cycling/bicycl*/cyclist AND air pollution, travel mode, inhalation/environmental/commuter/personal exposure, commuter/urban transport, environmental monitoring, active transportation, microenvironment, traffic, exposure assessment, particulate matter, health response/effects, acute, vehicle, emissions, toxicity, exercise, cost, injury, benefit, physical activity, risk, life expectancy, non-motorized transportation, risk assessment, health behaviour, built environment, health policy, public health, accidents, mortality, Scanned papers for additional references & new search terms added iteratively

8 Three major types of studies i) Measuring air pollution exposures of cyclists comparing route type or to other travel modes (N=18) ii) Assessing changes in health responses following cycling in proximity to traffic (N= 7 + 1) iii) Estimating health impacts and benefits of related to cycling under different scenarios, while considering air pollution (and sometimes physical activity and injuries) (N=6)

9 Three major types of studies i) Measuring air pollution exposures of cyclists comparing route type or to other travel modes (N=18) ii) Assessing changes in health responses following cycling in proximity to traffic (N= 7 + 1) iii) Estimating health impacts and benefits of related to cycling under different scenarios, while considering air pollution (and sometimes physical activity and injuries) (N=6)

10 Exposure & Intake EXPOSURE = CONCENTRATION x DURATION INTAKE = EXPOSURE x INHALATION Travel mode Route type Inhalation

11 Zuurbier et al. (2010) Environ Health Perspect. 118:783-9 Travel Mode

12 Ultrafine particles (UFP) & travel mode Knibbs et al. (2011) Atmos. Environ

13 Travel mode Authors Pollutant Location Car:Cycle Ratio Boogard et al, 2009 UFP 11 Dutch cities 1.0 Int Panis et al, 2010 UFP 3 Belgian cities ~1.0 Zuurbier et al, 2010 UFP Arnhem 0.9 Kaur et al, 2007 UFP London 1.1 Knibbs et al, 2011 UFP Summary 1.3 Adams et al, 2002 Black Carbon London 1.7 Summer 1.8 Winter Kingham et al, 1998 Black Carbon London 1.2 Gegisian et al, 2003 Black Carbon London 1.6 Zuurbier et al, 2010 Black Carbon Arnhem ~1.5 Dons et al, 2012 Black Carbon 3 Belgian cities 1.8

14 Travel mode Authors Pollutant Location Car:Cycle Ratio Adams et al, 2001 PM 2.5 London 1.1 Summer 1.4 Winter Kaur et al, 2007 PM 2.5 London 1.1 O'Donoghue et al, 2007 PM 2.5 Dublin 0.9 Zuurbier et al, 2010 PM 2.5 Arnhem ~1.2 Boogard et al, 2009 PM Dutch cities 1.1 Huang et al, 2012 PM 2.5 Beijing 0.6 (Taxi:Cycle) Zuurbier et al, 2010 PM 10 Arnhem 1.2 Huang et al, 2012 CO Beijing 2.7 (Taxi:Cycle) Van Wijnen et al, 1995 CO Amsterdam MacKay et al, 2004 CO Leeds 0.9 Kaur et al, 2007 CO London 1.2

15 Cycling routes and air pollutant exposure *Thai A, McKendry I, Brauer M. Particulate Matter Exposure along Designated Bicycle Routes in Vancouver, British Columbia. Science of the Total Environment, 2008.

16 Route Type (traffic level) Authors Pollutant Location High:Low traffic Route Ratio Strak et al, 2009 UFP Utrecht, Netherlands 1.6 Zuurbier et al, 2010 UFP Arnhem, Netherlands 1.4 Kaur et al, 2007 UFP London, UK 1.4 Knibbs et al, 2011 UFP Summary ~1.3 Kingham et al, 1998 Black Carbon London 2.3 Strak et al, 2009 Black Carbon Utrecht 1.4 Zuurbier et al, 2010 Black Carbon Arnhem 1.3 Adams et al, 2001 PM 2.5 London Zuurbier et al, 2010 PM 2.5 Arnhem 1.0 Strak et al, 2009 PM 2.5 Utrecht 1.0 Zuurbier et al, 2010 PM 10 Arnhem 1.0 Bevan et al, 1991 CO Southampton, UK 1.6 Bevan et al, 1991 VOCs Southampton ~2.0

17 Determinants of increased UFP peaks Activity Percent increase Passing mopeds 58 Passing cars 4 Intersections 8 10 Waiting for a traffic light Average waiting time for a traffic light was 25 seconds 10 Cycling on a marked bicycle lane (separated from vehicles by line marking only) 11 Cycling on adjacent, separated bike lane 8 Boogard et al. Atmos Environ. 2009

18 Barriers and separation Displacement of cycling paths 1-2 meters away from roads (e.g. small cement barriers or planters) reduced exposures of cyclists by 8 38%. Noise barriers (5 m high, 0.3 m thick) reduced roadside UFP levels 12-84% along adjacent bicycle/pedestrian pathway. Kendrick CM, Moore A, Haire A, Bigazzi A, Figliozzi M, Monsere CM, George L. The impact of bicycle lane characteristics on bicyclists exposure to traffic-related particulate matter. Transportation Research Record, # : Moore A, Kendrick C, Bigazzi A, Haire A, George L, Figliozzi M, Monsere C. Assessing Bicyclist and Pedestrian Exposure to Ultrafine 1 Particles: Passive Shielding with Noise Barriers TRB 2011 Paper Transportation Research Board Annual Meeting 2011 Paper #

19 Photo: BBC Author Inhalation Cyclist:Car ratio van Wijnen et al, O Donoghue et al, Zuurbier et al, Int Panis et al, males 4.5 females

20 Three major types of studies i) Measuring air pollution exposures of cyclists comparing route type or to other travel modes (N=18) ii) Assessing changes in health responses following cycling in proximity to traffic (N= 7 + 1) iii) Estimating health impacts and benefits of related to cycling under different scenarios, while considering air pollution (and sometimes physical activity and injuries) (N=6)

21 Authors Design Air pollution (UFP pt/cc) Jacobs et al, 2010; Bos et al, 2012 (Antwerp) Vinzents et al, 2005 (Copenhagen) Weichenthal et al, 2011 (Ottawa) Strak et al, 2010 (Utrecht) Zuurbier et al, 2011ab (Utrecht) Cole et al, 2012 (Vancouver) N=38, 20 min cycle in traffic vs filtered air in lab N=15, 90 min cycle in traffic (6 days) vs in lab N=42, 60 min cycle in high vs low traffic vs in lab N=12, 60 min cycle high vs low traffic routes N=34, 2 hr cycle vs car, bus commute (5-12 days) Dose: Bus: Car: Cycle High traffic: 59 Cycle Low traffic: 50 N=38, 1 hr cycle in high vs low traffic 29, ,400 (not measured in lab) 20,000 11,000 1,200 44,000 28,000 Bus: 32,00-45,000 Car: 35,00-39,000 High traffic cycle: 42,000 Low traffic cycle: 36,000 16,000 10,000 Outcomes 3.9 % increase in blood neutrophils No associations for exhaled NO, platelet function, Clara cell protein, Serum brain derived neurotrophic factor 4-fold increase in level of oxidative DNA base damage No association with DNA strand breaks. 4 hrs post ride: Decreased heart rate variability No associations with lung functions, exhaled NO 0 hrs post-ride: increased lung function 6 hrs post: (non-significant) decreased lung function, increased exhaled NO. UFP dose associated with increased CRP No association for blood cell counts, markers of lung epithelial damage, coagulation or inflammation. UFP dose associated with decreased airflow and increased airway resistance No association with exhaled NO (effects not specific to cycling)

22 Vinzents et al, 2005 DNA oxidative damage

23 Three major types of studies i) Measuring air pollution exposures of cyclists comparing route type or to other travel modes (N=18) ii) Assessing changes in health responses following cycling in proximity to traffic (N= 7 + 1) iii) Estimating health impacts and benefits of related to cycling under different scenarios, while considering air pollution (and sometimes physical activity and injuries) (N=6)

24 Authors Location Change Risk Benefit Balance Grabow et al, % shift of car round trips of 8 km to cycling. None evaluated Physical activity Reduced air pollution Lindsay et al, 2010 Woodcock et al., 2009 de Hartog et al., 2010 Rabl & de Nazelle, 2012 Rojas- Rueda et al., 2011 Midwest USA, 11 metro areas New Zealand London, England Netherlan ds Europe Barcelona, Spain 5% shift in Vkmt for trips < 7km, adults. Increased active transportation: 2X walking & 8X cycling. 500,000 adults switch from car to bicycle for trips < 7.5 km. Driver who switches to 5 km of cycling for work commute 181,982 public bike share users, compared to car use. Traffic crashes Traffic crashes Traffic crashes Air pollution Traffic crashes Air pollution Traffic crashes Air pollution Physical activity Reduced air pollution Physical activity Reduced air pollution Physical activity Physical activity Reduced air pollution (reduced noise and congestion) Physical activity Reduced air pollution Combined effect: 1,129 fewer deaths/ 31.9 million population = 35 fewer deaths/million population / year. Benefit to risk ratio: no risks considered. Combined effect: 117 fewer deaths / 2.7 million population = 43 fewer deaths/million population/year. Benefit to risk ratio ~ 24:1 (deaths) Combined effect: 530 fewer premature deaths and 7,332 more disability-adjusted life-years per million population per year. Benefit to risk ratio: ~ 49:1 (deaths); ~ 15:1 (DALYs) Combined effect: gain of 7 months of life per person = 583,333 years/million population over life course. Benefit to risk ratio: ~ 9:1 Combined effect: gain of 1,271 Euros/yr per car driver who switches to cycling = 1.3 billion Euros/yr per million car drivers who switch. Benefit to risk ratio: ~ 19:1 Combined effect: 12.3 fewer deaths per year = 67 fewer deaths per million population per year. Benefit to risk ratio: ~ 96:1

25 Cycling benefits outweigh risks The Netherlands: Modal shift (Cars Bikes), N=500,000 (short trips) 1 Physical activity: life-day increase Air pollution: life-day decrease Traffic accidents 5-9 life-day decrease Barcelona Bicing bike share (181,982 users) 2 Physical activity: 12 deaths avoided Air pollution: 0.13 increased deaths Traffic accidents: 0.03 increased deaths 1 De Hartog et al. 2010, 2 Rojas-Rueda et al., 2011

26 Summary Compared to other travel modes, cyclists experience similar or slightly lower pollutant CONCENTRATIONS, however cyclists receive increased pollution INTAKE due to increased inhalation Travel duration: pedestrians > cyclists > motor car Concentrations of primary traffic pollutants can differ dramatically based on route type Some evidence of subtle health impacts amongst cyclists in traffic compared to low/no traffic routes Overall cycling health benefits clearly greater than impacts of increased air pollution dose

27 Implications Cycling is beneficial, but some negative impacts due to traffic pollutant exposures Negative impacts can be reduced by increased separation Barriers Residential routes (1 block displacement) Alternate bike and car friendly roads. Bike paths Route planner ( Cyclists willing to detour 400 m (~2 blocks) to bike route Su J et al. Designing a route planner to facilitate and promote cycling in Metro Vancouver, Canada. Transportation Research Part A: Policy and Practice, 2010, 44: ; Winters M et al. How far out of the way will we travel? Built environment influences on route selection for bicycle and car travel. Transportation Research Record. 2190:

28 Thank you!

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30 Cycling route planner Su J, Brauer M, Winters M, Nunes M. Designing a route planner to facilitate and promote cycling in Metro Vancouver, Canada. In press, Transportation Research Part A: Policy and Practice, 2010, 44:

31 UFP: Passing mopeds (58%) and to a lesser extent passing cars (4%), Intersections (8-10%) with a right-of-way road, Waiting for a traffic light (10%). Average waiting time for a traffic light was 25 Cycling on a marked bicycle lane (separated from vehicles by line marking only) (11%) Boogard et Cycling al. Atmos adjacent, Environ. separated 2009 bike lane (8%)