Winter Maintenance
During the winter months, most countries will undertake winter maintenance practices. This involves spraying brine or grit (rock salt) across the road in order to prevent ice forming upon the surface, thereby helping to reduce accidents. Some countries also allow the use of studded tires but this is slowly being phased out due to the increase in road surface wear caused by the studs breaking up the road surface. Measurements carried out in the UK also show a large increase in particle concentrations after the application of grit to the road surface. Patra et al., (2008) noted the levels of particles in the atmosphere increased by a factor of 15.
The majority of grit used within the UK is rock salt, spread over the road surface using gritting lorries with a metal trailer, which stores the grit ready for spreading. The majority of grit is sodium chloride but contamination can occur. Legret and Pagotto (1999) found de-icing agents used within France contained quantities of lead (3.3 mg/kg), copper and zinc (0.5 mg/kg) and cadmium (0.2 mg/kg). Due to these issues and their ability to significantly increase particle concentrations, winter maintenance practices should also be considered as a source of non-exhaust emissions and regulated accordingly.
Find out how you could reduce your non-exhaust emissions