The popularity of cycling in London continues to rise: according to statistics published by Transport for London (TfL), the number of journeys made by bicycle in London grew by 5 per cent in 2018. The transport agency has attributed the upwards trend in cycling to its investment in cycling infrastructure, not least the seven Cycle Superhighways and 12 Cycle Quietways the city now boasts.
Cycling is widely reported to result in health benefits for participants, and cyclists can expect to achieve improvements in both their physical and mental health as a result of switching from public transport or car to a bike. But with air pollution levels remaining stubbornly high across London, should cyclists be concerned that the health benefits they achieve as a result of cycling are actually being outweighed by the dangers posed by increased exposure to air pollution?
Unlike during the Great Smog of 1952, air pollution today is often invisible to the naked eye. Nonetheless, London breached the European and UK air quality annual limit on 18 March when, for the 36 time this year, levels of pollution particles recorded at a measuring post exceeded the agreed limit. (EU rules allow 35 breaches a year.) Whilst this is a marked improvement on 2018 when the annual limit was broken on the 5 January, it reminds us of the risk that air pollution continues to pose to Londoners today.
The rise of respirator masks
Anyone who has cycled or walked along one of London's cycle paths in recent years is likely to have seen someone resembling Darth Vader cycling towards them. Protection masks, which are becoming increasingly popular amongst the cycling community, range from cotton surgical masks to respirators with in-built air filtration systems that cover a significant part of the cyclist’s face.
But do masks actually work and are they worth the investment?
Cotton masks categorically do not protect wearers against the inhalation of airborne particles. Whilst they can be somewhat effective in protecting against the spread of illnesses, they will not protect a cyclist from air pollution.
Respirator cycling masks, which range in price from £25 to over £50, are a more sophisticated option. “N99” respirators are said to remove up to 99 per cent of airborne particles from inhaled air. But the particles that cause air pollution today are extremely small, which makes it particularly challenging for respirators to effectively block them from entering the human body.
Another complicating factor is the fit of the respirator against the human face. Studies have concluded that under “perfect” conditions respirators do effectively filter pollution out of inhaled air. However, when actually fitted to a human face, respirators are often not able to form an effective seal against skin, which ultimately renders them useless. Features such as facial hair and short noses make is particularly challenging for a seal to form.
The findings of studies into the effectiveness of respirator cycling masks are somewhat mixed – but point to the ineffectiveness of current designs.
So what can cyclists do to protect themselves?
The best intervention a cyclist can make to reduce their exposure to air pollution is to avoid the most polluted streets and roads. TfL’s Quietways are an easy way for cyclists to identify the less busy and less polluted roads (although TfL has announced it will be merging the Quietway and Cycle Superhighway networks into a single Cycleways cycle network during summer 2019).
Cyclists may also consider reducing their cycling speed to reduce their inhalation of airborne particles. The faster and deeper we breathe in polluted air, the more pollutants are delivered to our lungs. Therefore slowing down and reducing their amount of exertion will go some way to protecting cyclists from air pollution.
Finally, cyclists should check air quality forecasts and make informed decisions regarding their chosen mode of transport on a particular day. TfL provides daily forecasts on its website.
So should cyclists stop cycling all together? In a word, no. Although there is currently not an effective way to stop yourself from inhaling air pollution whilst cycling, scientists have concluded that the physical and mental health benefits of cycling continue to outweigh the dangers posed by exposure to air pollution. Cycling remains a healthy method of transport for Londoners.
If you are a cyclist who is concerned about your exposure to air pollution and you are considering investing in a respirator mask, be aware that research suggests they will not protect you effectively. Instead you may want to consider donating the money you would have spent on a respirator to a charity such as Trees for Cities, whose mission is to transform urban areas by creating Urban Forests.