TY - JOUR
T1 - Characteristics of tyre dust in polluted air
T2 - Studies by single particle mass spectrometry (ATOFMS)
AU - Dall'Osto, Manuel
AU - Beddows, David C S
AU - Gietl, Johanna K.
AU - Olatunbosun, Oluremi A.
AU - Yang, Xiaoguang
AU - Harrison, Roy M.
PY - 2014/9/1
Y1 - 2014/9/1
N2 - There is a paucity of quantitative knowledge on the contributions of non-exhaust (abrasion and re-suspension) sources to traffic emissions. Abrasive emissions can be broadly categorised as tyre wear, brake wear and road dust/road surface wear. Current research often considers road dust and tyre dust as externally mixed particles, the former mainly composed of mineral matter and the latter solely composed of mainly organic matter and some trace elements. The aim of this work was to characterise tyre wear from both laboratory and field studies by using Aerosol Time-Of-Flight Mass Spectrometry (ATOFMS). Real-time single particle chemical composition was obtained from a set of rubber tyres rotating on a metal surface. Bimodal particle number size distributions peaking at 35nm and 85nm were obtained from SMPS/APS measurements over the range 6-20,000nm. ATOFMS mass spectra of tyre wear in the particle size range 200-3000nm diameter show peaks due to exo-sulphur compounds, nitrate, Zn and ions of high molecular weight (m/z>100) attributed to organic polymers. Two large ATOFMS datasets collected from a number of outdoor studies were examined. The former was constituted of 48 road dust samples collected on the roads of London. The latter consisted of ATOFMS ambient air field studies from Europe, overall composed of more than 2,000,000 single particle mass spectra. The majority (95%) of tyre wear particles present in the road dust samples and atmospheric samples are internally mixed with metals (Li, Na, Ca, Fe, Ti), as well as phosphate. It is concluded that the interaction of tyres with the road surface creates particles internally mixed from two sources: tyre rubber and road surface materials. Measurements of the tyre rubber component alone may underestimate the contribution of tyre wear to concentrations of airborne particulate matter. The results presented are especially relevant for urban aerosol source apportionment and PM2.5 exposure assessment.
AB - There is a paucity of quantitative knowledge on the contributions of non-exhaust (abrasion and re-suspension) sources to traffic emissions. Abrasive emissions can be broadly categorised as tyre wear, brake wear and road dust/road surface wear. Current research often considers road dust and tyre dust as externally mixed particles, the former mainly composed of mineral matter and the latter solely composed of mainly organic matter and some trace elements. The aim of this work was to characterise tyre wear from both laboratory and field studies by using Aerosol Time-Of-Flight Mass Spectrometry (ATOFMS). Real-time single particle chemical composition was obtained from a set of rubber tyres rotating on a metal surface. Bimodal particle number size distributions peaking at 35nm and 85nm were obtained from SMPS/APS measurements over the range 6-20,000nm. ATOFMS mass spectra of tyre wear in the particle size range 200-3000nm diameter show peaks due to exo-sulphur compounds, nitrate, Zn and ions of high molecular weight (m/z>100) attributed to organic polymers. Two large ATOFMS datasets collected from a number of outdoor studies were examined. The former was constituted of 48 road dust samples collected on the roads of London. The latter consisted of ATOFMS ambient air field studies from Europe, overall composed of more than 2,000,000 single particle mass spectra. The majority (95%) of tyre wear particles present in the road dust samples and atmospheric samples are internally mixed with metals (Li, Na, Ca, Fe, Ti), as well as phosphate. It is concluded that the interaction of tyres with the road surface creates particles internally mixed from two sources: tyre rubber and road surface materials. Measurements of the tyre rubber component alone may underestimate the contribution of tyre wear to concentrations of airborne particulate matter. The results presented are especially relevant for urban aerosol source apportionment and PM2.5 exposure assessment.
KW - ATOFMS
KW - Non-exhaust emissions
KW - Road surface wear
KW - Road traffic
KW - Tyre dust
UR - http://www.scopus.com/inward/record.url?scp=84901301237&partnerID=8YFLogxK
U2 - 10.1016/j.atmosenv.2014.05.026
DO - 10.1016/j.atmosenv.2014.05.026
M3 - Article
AN - SCOPUS:84901301237
SN - 1352-2310
VL - 94
SP - 224
EP - 230
JO - Atmospheric Environment
JF - Atmospheric Environment
ER -