Tuesday, June 4, 2013

When it comes to air quality, bicycling is really healthy?

Bicycling is encouraged to use as the sustainable alternative of an automobile. On individual level, it gives health benefits by increasing physical activities and reduces transportation cost. On social level, it improves air quality, public health, congestion, and gas consumption.  In spite of promoting a bicycling is advantageous  in terms of a social cost, there has been debates on health benefits of bicycling.

According to  Weichenthal et al., gas emission from vehicles likely affect on heart rate variability. In their experiment, high frequency power of heart was decreased after cycling in congested routes compared to indoor bicycling. Rojas-Rueda et al. examined the health benefits and hazards of bicycling. They concluded that the benefits of bicycling were greater than the risks of it after comparing mortality of road traffic crashes and deaths caused by polluted air with the number of mortality avoided due to the increase in physical activities. Furthermore, annual carbon dioxide emissions were dropped because of the shift of mode choice from automobile to bicycle.

It seems that there has been no consensus on the health effects by bicycling as alternative of driving. When it comes to the main source of adverse health effects of bicycling, it is caused not by bicycles but by vehicles. Polluted gas emission from vehicles directly affects on bicyclists who contribute to improving air quality by not driving like other drivers. Are there any ways to reduce the negative influence of vehicles on the health of bicyclist? One clue could be found from a research by Weichenthal et al.

In their research, the intensity of polluted air which participated bicyclists inhaled was monitored. The results showed that high-traffic routes had greater air pollutants including UFP, BC, and PM2.5 concentrations compared to low-traffic routes.  It indicates that the greater expose to gas emission makes adverse health impacts to bicyclists getting worse.

For all registered vehicles in Oregon, department of Environmental Quality(DEQ) operates vehicle emission test. Depending on a vehicle year, type of test is determined. Basic emissions test monitors the level of carbon monoxide and hydrocarbon in gas emission from vehicles. For newer vehicles, on-board diagnostics test is performed to check emission systems working properly. Air quality of Oregon seems to be good in terms of air quality index, since all areas in Oregon meet federal health standards for air pollution. Clean air strategies including vehicle emission tests which are administrated by DEQ have created positive results. For a reference, in 1980, only 30 percent of Oregon area was in a satisfactory air quality condition. On the other sides, there are still concerns in air quality of Oregon. Air toxic is that distress.

 Air toxics are polluted air which triggers cancers and other serious health problems related to nerve damage and respiratory irritation. Vehicles are one of major sources of air toxics. Air toxics generated from vehicle include benzene, 1,3-butadiene, formaldehyde, acetaldehyde, acrolein, polycyclic organic matter, naphthalene, and diesel particulate matter. These air toxics directly affect neurological, cardiovascular, liver, kidney, and respiratory, immune and reproductive systems. There are no national health standards for air toxics. In the meanwhile, the level of several air toxics in Oregon area exceeds clean air health goals, and Portland region has the highest air toxic concentrations.

There will be various approaches to make bicycling in Oregon as a safer activity for the perspective of air quality. One of it would be the inclusion of  air toxics as criteria in vehicle inspection program. Reminding that the greater exposes result in the greater adverse health effects for bicyclists. Prior to modify a current gas emission test program, it is also required to set standards for air toxics generated from vehicles. Bicyclists often share roads with vehicles. For the case, bicyclists take higher health risks at the intersection where vehicles are idling so that  they inhale directly air toxics of vehicles. It is known that vehicles generate much air pollutants while vehicles idle. By regulating air toxics through vehicle inspection program,  the amount of exposed air toxics to bicyclists in a densely developed area such as Portland would be decreased.   

One of good programs for providing a less polluted environment for cyclists would be voluntary accelerated vehicle retirement program which is implemented in California. California provides monetary incentives to promote a voluntary retirement of vehicles when vehicles fails to pass gas  emission test.  At local level, even vehicles passing gas emission test are eligible to apply to get monetary incentives for the sake of scrapping their vehicles. The implementation of the program in Oregon will reduce the use of old vehicles which tend to  produce more polluted air. It would improve not only public air quality but also provide a safer environment of bicycling.  

*Academic References
1. de Nazelle, A. et al. (2011). Improving Health Through Policies That Promote Active Travel: A Review of Evidence to Support Integrated Health Impact Assessment. Environment International. 37. 766-777.
2. Rojas-Rueda, D., Nazelle, A.D., Tainio, M., Nieuwenjuijsen, M.J, 2011. "The health risks and benefits of cycling in urban environments compared with car use: health impact assessment study", British Medical Journal . 343. 

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