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A new method for determination of relative contribution of aerosol sources to the oxidative potential of PM

A new method for determination of relative contribution of aerosol sources to the oxidative potential of PM

Exposure to combustion-derived air pollution aerosols has been shown to have many adverse effects on human health, including the impact of cellular oxidative stress. In this toxicological study we developed a new method to assess the contribution of different sources of ambient aerosols to the oxidative potential (OP) of particulate mass (PM), using a long time series of PM10 samples.

The OP was measured on filter samples collected over a full year in the Alpine valley city of Chamonix (France), using two OP protocols: ascorbic acid (AA) and dithiothreitol (DTT) assays. We used PMF analysis from an advanced source-receptor model to obtain source apportionment, and inverted the OP measurements in order to attribute both an intrinsic OP to the sources and the evolution of the source contributions to OPs over the year.

Our results highlight the importance of both biomass burning and vehicular sources as the major contributors to OP in both assay methods. Significant differences were observed between the DTT and AA protocols. This emphasizes the chemical specificities of these tests and the need for a standardized approach for future studies of the epidemiology or toxicology of PM.

The article was published in Atmospheric Chemistry and Physics:
An apportionment method for the oxidative potential of atmospheric particulate matter sources: application to a one-year study in Chamonix, France

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Comparison of a traffic emissions model with measurements in a European city

Comparison of a traffic emissions model with measurements in a European city

Dr. Irena Ježek of the Aerosol R&D team just published a scientific paper in the prestigious journal Atmospheric Environment titled: “The traffic emission-dispersion model for a Central-European city agrees with measured black carbon apportioned to traffic”. This scientific paper presents a simple methodology for modeling traffic emissions using real world emission factors. Using real-world emission factors in the model is essential, to make the emissions representative of the actual in-use fleet. This is the only way in which emission reduction strategies can be planned, that target vehicles that pollute the most.

The research shows how an improved understanding of traffic emissions and impacts, can lead to improved management and legislative controls. The model’s results were verified with in-situ measurements of Black Carbon apportioned to traffic with the Aethalometer model, and showed excellent agreement. The most efficient emission reduction scenarios were those where the highest polluting vehicles were targeted. Removing 10% of the highest polluting vehicles would reduce BC concentrations in the city center by 39%, and NOx by 33%.

We would like to thank Suzana Pranjc and the Office of Utility, Transport and Spatial Planning of the Municipality of Maribor; the Slovenian Ministry of Infrastructure; the Slovenian Environment Agency; and the Slovenian National Laboratory of Health, Environment and Food; for contributing data to the analyses presented in this pubclication.

This research was supported by the European Social Foundation, (SPIRIT), contract no. P-MR-10/04.

The traffic emission-dispersion model for a Central-European city agrees with measured black carbon apportioned to traffic
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Heating Rate of Light Absorbing Aerosols

Heating Rate of Light Absorbing Aerosols

Scientific paper published in Environmental Science & Technology journal presents a novel methodology for experimental quantification of heating rate induced by light absorbing aerosols (LAA) (Black Crabon – BC and Brown Carbon – BrC) into an atmospheric layer.

Multiwavelength aerosol absorption measurements, performed by the Aethalometer, were coupled with spectral measurements of the direct, diffuse and surface reflected radiation to obtain highly time-resolved measurements of heating rate apportioned in the context of LAA species (BC, BrC, dust), sources (fossil fuel, biomass burning), and as a function of cloudiness.

One year of continuous and time-resolved measurements of heating rate were performed in the Po Valley, which allowed experimental determination of its seasonal behavior and daily cycle.

Heating Rate of Light Absorbing Aerosols: Time-Resolved Measurements, the Role of Clouds, and Source Identification

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EXPOSURE TO BLACK CARBON DURING CYCLING

EXPOSURE TO BLACK CARBON DURING CYCLING

In the 2017 winter-spring period we performed static and mobile measurements of Black Carbon using our Aethalometers at different sites and cycling routes in Celje, Slovenia.
The results show that street intersections along the cycling routes influence the cyclists’ exposure to Black Carbon and should be as few as possible when planning cycling routes in urban areas.
Exposure can be greatly reduced by moving the cycling route away from busy roads, hence we proposed an alternative route and show that traffic planning and management should include all modes of transport.

Exposure to Black Carbon during Bicycle Commuting–Alternative Route Selection

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