The short video below shows that the highest concentration of air pollutants exists along the main roads and peaks at the junctions, mainly due to the slow moving or stagnant vehicles stuck in traffic. Areas that are further away from the main roads are clearly better.
According to WHO (World Health Organization), the negative health effects of different pollutants are different. Ultrafine Particles, such as the 0.1-0.3Microns, can travel deep into our lungs and reside there longer than their older brothers, the PM10, >10microns and PM2.5microns.
Some 3.7 million premature deaths annually are attributed to outdoor air pollution. About 80% of those deaths are due to heart disease and stroke, while another 20% are from respiratory illnesses and cancers related to exposure to fine particulate matter (PM2.5), the most health-harmful air pollutant.
It has been proven long ago that ultra fine particles reduces the health benefits of physical exercises. Increased evidences have showed that these ultra fine particles are the culprits of respiratory and cardiovascular illnesses. According to UCLA, the smaller the particles, the more toxic chemicals they are able to carry. These ultra fine particles are capable of traveling deep into our lungs, they stick to our lungs and releases the chemicals they have brought along with them which damages our blood vessels and causes our blood to solidify, forming blood plaques. Places such as traffic junction and busy roads have the worst exposure to these pollutants. Therefore, it isn’t a silly idea to be wearing a filter mask while cycling through the busy traffic. However, you’ll have to make sure that the mask you own forms a good seal on your face and that the filters are able to filtrate the ultra fine particles (0.1micron and PM2.5).
Totobobo filter test against ultrafine particles (0.1 microns) Test report Shop for Totobobo Mask!