At 204060 km per hour...
Acceleration in vehicles increases ultrafine particles
when vehicles accelerate after stopping at a traffic light or a bus stop, the concentration of ultrafine particles increases, says a Hong Kong-based study. Ultrafine particles, less than 0.1 micron in diameter, are a fraction of particulate matter. It is considered as a significant human health concern because of its small size, large numbers and their ability to enter the respiratory tract and the circulatory system. The study aimed to evaluate the exposure of pedestrians to vehicular emissions of ultrafine particles while walking near several high volume pedestrian walkways. The findings were published in Aerosol and Air Quality Research (Vol 8, No 1).
Researchers chose three locations around a busy intersection in the city. They found the highest particle count in one of the locations and superimposed traffic patterns on the particle count versus time data for that location. Explains Hamilton Tsang, one of the lead researchers,