Multi-element analysis of tyre rubber for metal tracers

Area of Science:

• Environmental Chemistry
• Atmospheric Science
• Materials Science

Background:

• Zinc is currently used as a tracer for tyre wear in atmospheric studies, but this approach has limitations.
• Existing tyre wear source profiles in databases are outdated and lack comprehensive coverage of current tyre models.

Purpose of the Study:

• To establish a characteristic elemental fingerprint for tyre wear particles.
• To improve the accuracy of atmospheric source apportionment calculations for tyre wear.
• To provide updated elemental composition data for contemporary European tyres.

Main Methods:

• Digestion and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis of tyre tread for 25 elements.
• Thermogravimetric analysis (TGA) to determine inert filler content.
• Comparative analysis of passenger car vs. heavy goods vehicle tyres, and tread vs. sidewall composition.

Main Results:

• 19 of 25 elements were detected, with zinc being the most abundant (mean mass fraction 11.17 g/kg).
• Aluminium, iron, and magnesium were identified as the next most abundant elements.
• Elemental profiles differed between tyre types and sampled parts (tread vs. sidewall).

Conclusions:

• A multielemental approach offers a more robust fingerprint for tyre wear particles than single-element tracers.
• Updated elemental composition data for current tyres are crucial for accurate atmospheric source apportionment.
• This research provides relevant data for ongoing urban air quality studies on tyre wear particle levels.