Oxidative potential of PM2.5 and PM10 in an urban background site in Lecce: influence of combustion sources and Saharan dust advection


  • Daniele Contini Istituto di Scienze dell’Atmosfera e del Clima, CNR - Lecce
  • Daniela Chirizzi Istituto Zooprofilattico Sperimentale di Puglia e Basilicata - Foggia
  • Maria Rachele Guascito Istituto di Scienze dell’Atmosfera e del Clima, CNR - Lecce
  • Adelaide Dinoi Istituto di Scienze dell’Atmosfera e del Clima, CNR - Lecce
  • Livia Giotta Dipartimento di Scienze e Tecnologie Biologiche e Ambientali, Università del Salento - Lecce
  • Antonio Donateo Istituto di Scienze dell’Atmosfera e del Clima, CNR - Lecce
  • Fabio Massimo Grasso Istituto di Scienze dell’Atmosfera e del Clima, CNR - Lecce
  • Daniela Cesari Istituto di Scienze dell’Atmosfera e del Clima, CNR - Lecce




Oxidative potential, PM 2.5, PM 10, Saharan dust, health risks


Exposure to atmospheric particulate matter (PM) leads to adverse health effects and the exact mechanisms of toxicity are still not completely understood. Recent studies suggested that a large number of PM health effects could be due to the oxidative potential (OP) of ambient particles leading to high concentrations of reactive oxygen species (ROS). However, information about the OP of natural sources are scarce and no data is available regarding the OP during Saharan dust outbreaks (SDO) in Mediterranean regions. This work uses the a-cellular DTT (dithiothreitol) assay to evaluate OP of the water-soluble fraction of PM2.5 and PM10 collected at an urban background site in Southern Italy. DTT activity normalised by sampled air volume (DTTV), representative of personal exposure, and normalised by collected aerosol mass (DTTM), representing source-specific characteristics, were investigated. DTTV was larger for high carbon content samples but during SDO events was statistically comparable with that of samples representative of typical conditions for this area. DTTM was larger for PM2.5 compared to PM10 and the relative difference between the two size fractions was maximised during SDO events. This suggests that Saharan dust is a natural source of particles with low OP and that DTTV could be a useful indicator in epidemiological studies, especially in regions frequently affected by Saharan dust advection.


Bates, J.T., Weber, R.J., Abrams, J., Verma, V., Fang, T., Klein, M., Strickland, M.J., Sarnat, S.E., Chang, H.H., Mulholland, J.A., Tolbert, P.E., Russell, A.G., 2015. Reactive oxygen species generation linked to sources of atmospheric particulate matter and cardiorespiratory effects. Environ. Sci. Technol. 49, 13605-13612.

Cesari D., De Benedetto G.E., Bonasoni P., Busetto M., Dinoi A., Merico E., Chirizzi D., Cristofanelli P., Donateo A., Grasso F.M., Marinoni A., Pennetta A., Contini D., 2018. Seasonal variability of PM2.5 and PM10 composition and sources in an urban background site in Southern Italy. Science of the Total Environment 612, 202–213.

Chirizzi D., Cesari D., Guascito M.R., Dinoi A., Giotta L., Donateo A., Contini D., 2017. Influence of Saharan dust outbreaks and carbon content on oxidative potential of water-soluble fractions of PM2.5 and PM10. Atmospheric Environment 163, 1-8.

Cho, A.K., Sioutas, C., Miguel, A.H., Kumagai, Y., Schmitz, D.A., Singh, M., Eiguren-Fernandez, A., Froines, J.R., 2005. Redox activity of airborne particulate matter at different sites in the Los Angeles Basin. Environ. Res. 99, 40-47.

Contini, D., Cesari, D., Donateo, A., Chirizzi, D., Belosi, F., 2014. Characterization of PM10 and PM2.5 and their metals content in different typologies of sites in South-Eastern Italy. Atmosphere 5, 435–453.

Delfino, R.J., Sioutas, C., Malik, S., 2005. Potential role of ultrafine particles in associations between airborne particle mass and cardiovascular health. Environ. Health Perspect. 113, 934-946.

Delfino, R.J., Staimer, N., Tjoa, T., Gillen, D.L., Schauer, J.J., Shafer, M.M., 2013. Airway inflammation and oxidative potential of air pollutant particles in a pediatric asthma panel. J. Expo. Sci. Environ. Epidemiol. 23, 466-473.

Dinoi, A., Donateo, A., Belosi, F., Conte, M., Contini, D. 2017. Comparison of atmospheric particle concentration measurements using different optical detectors: Potentiality and limits for air quality applications. Measurement 106, 274–282.

Li, N., Sioutas, C., Cho, A., Schmitz, D., Misra, C., Sempf, J., Wang, M., Oberley, T., Froines, J., Nel, A., 2003. Ultrafine particulate pollutants induce oxidative stress and mitochondrial damage. Environ. Health Perspect. 111, 455-460.

Li, N., Wang, M., Bramble, L.A., Schmitz, D.A., Schauer, J.J., Sioutas, C., Harkema, J.R., Nel, A.E., 2009. The adjuvant effect of ambient particulate matter is closely reflected by the particulate oxidant potential. Environ. Health Perspect. 117, 1116-1123.

Pope, C.A., Burnett, R.T., Thurston, G.D., Thun, M.J., Calle, E.E., Krewski, D., Godleski, J.J., 2004. Cardiovascular mortality and long-term exposure to particulate air pollution epidemiological evidence of general pathophysiological pathways of disease. Circulation 109, 71-77.

Saffari, A., Daher, N., Shafer, M.M., Schauer, J.J., Sioutas, C., 2014. Seasonal and spatial variation in dithiothreitol (DTT) activity of quasi-ultrafine particles in the Los Angeles Basin and its association with chemical species. J. Environ. Sci. Health 49 (Part A), 441-451.

Verma, V., Fang, T., Guo, H., King, L., Bates, J.T., Peltier, R.E., Edgerton, E., Russell, A.G., Weber1, R.J., 2014. Reactive oxygen species associated with water-soluble PM2.5 in the southeastern United States: spatiotemporal trends and source apportionment. Atmos. Chem. Phys. 14, 12915-12930.