When riding bikes in an urban environment, especially in global locations where smog is not regulated as heavily as in the United States, the health benefits of an air pollution face mask are important to your long term health. This insightful video gives a first hand example of using a face mask in Thailand.
Look at the difference between the new mask and mask being used after two weeks of cycling! The difference is disgusting. If the mask were not trapping the black particles of dust in the air they would end up in your lungs. Very insightful video for cyclists looking for ways to improve their overall health in polluted urban environments.