Masking Out City Smog

20 February 2007, source edie newsroom

Wearing a mask can send a powerful message about pollution to motorists

Cyclists are not the only commuters exposed to cancer-causing pollutants in city air

Pollution masks may not be the ultimate answer to the dirty air and disease-causing particles we breathe in every day, but they are the solution more and more people are turning to in smoggy cities like London. So are we heading for an urban future where leaving the house without protection becomes too much of a risk? Here, Elaine Curtin from pollution mask makers Respro sets out the horrors of what urban dwellers are already breathing in each day - and how a mask can help.

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Although pollution masks are not just for cyclists, they certainly have roots in the world of cycling and it was cyclists who first embraced the pollution-filtering technology, prompting the name "cycle masks."

In fact Harry Cole, product designer for Respro, the UK's top producer of cycle masks, is an ex-London cycle courier who had "in your face" experience of exhaust fumes and city smog while working as a courier in the 1990s - a problem we still have today.

In 1990 Respro launched the City mask, the first cyclist pollution mask that remains in great demand. Over the last decade awareness of air pollution has grown, and now consumers can choose from a wider range of styles and filters to accommodate more individual needs.

Air pollution is a killer - four times as many people die from PM10 pollutants as traffic accidents in London. Ken Livingstone recognises this in his foreword to the Best Practice Guidance on the control of dust and emissions from construction and demolition, published by the Mayor of London and the London Councils in November 2006. The document emphasises that London suffers from high levels of air pollution and that "poor air quality damages peoples' health and affects their quality of life."

In 2005 it was estimated that approximately 1,000 accelerated deaths and 1,000 extra respiratory hospital admissions occurred in London as a result of PM10 air pollution.

In truth, Londoners only have to see what lorries and buses are kicking out to be sold into the concept of protecting their health. Masks provide the only way to block out lung irritants and other pollutants, many of which are carcinogens.

Pollution particulates can be classed as "inhalable" and "respirable." Inhalable particulates are the particles big enough to be trapped within the nasal hairs and the mucous membranes at the back of the throat. These are greater than one micron in size (1mm is equal to 1,000 microns; 0.1 micron is one thousandth of a millimetre in size).

Respirable particulates are the particles that pass beyond the nasal hairs and the mucous membranes of the throat and pass into the lung sacs and subsequent blood barrier. These are less than one micron in size. These particulates can carry carcinogenic chemicals used in petrol (benzene, pyrene, etc) to the blood barrier.

So what can an anti-pollution mask do to help? Masks help prevent lung irritation and cancer. Many different pollutants - when mixed together - can cause irritation to respiratory systems. Wearing a mask helps to prevent cancer as there are known carcinogenic agents such as pyrene and benzene present in petrol fumes.

There are also less weighty reasons for wearing a mask. The masks are an awareness statement to the other road users in cleaning up the environment. And as the mask covers part of the face, people feel their gender isn't evident, which can be an issue for cyclists.

The performance test data for Respro Masks' particulate filter media show that 99% of all particles over 0.3 micron in size will be trapped in the filter media.

It is believed that most airborne particluates are in the range of 0.1- 10 microns in size. The fitration performance for particulates are less than 0.3 microns would reduce at a linear rate which suggests that effective filtration greater that 50% would still occur at sizes well below 0.3 microns.

When particles reduce to the molecular (nano size) level they then get trapped by the attractive forces of the pore structure of the Dynamic Activated Charcoal Cloth element that is situated behind the particle filter. The combination of particle and activated charcaol filters in some of Respro's masks really does afford effective filtration at all levels of particulate size. To consider wearing a mask useless and suggest that people should not bother is irresponsible advice.

As for bigger particles, Respro masks block out everything - including pollen, grit, dust, brake lining dust, building dust, clay dust, diesel particulates etc.

Respro develops their masks from the technology used in the industrial market, including the Defence Establishment for the protection of military personnel. The masks are made with materials used in the industrial market for the protection of workers who would be putting their health at risk in their work environments if they failed to wear adequate protection.

The company uses the same testing procedures for its products to ensure that they do work. Detailed analysis of filtration and performance are measured to decide the ability of the product.

The masks are fitted with dynamic activated charcoal cloth (DACC), the filter media, plus micron level or "Hepa-type" particle filters in some masks. DACC was originally developed by the UK Ministry of Defence for use in the protection against chemical and bacteria warfare situations. Respro uses DACC to effectively filter out Primary pollutants associated with vehicle exhaust emissions such as gases and vapours, including nitrogen oxides, sulphur dioxide, carbon monoxide, low level ozone, and hydrocarbon chemicals.

While cyclists are particularly exposed to air pollution, there are many other groups and situations that make wearing a mask is particularly important. Daily commuters travelling in or out of rush hour periods are a group particularly vulnerable to lung damage from air pollution. Other high-risk situations include environments when there is low air velocity i.e. still air and not much wind. Sunny days can also be particularly dangerous for the lungs - photochemical smog produces low level ozone which can cause irritation to those with asthmatic tendencies or susceptible lungs.