Stable carbon isotope ratio measurements in aerosol particles, generated from various internal combustion engines

Abstract

Aerosol particles play important role in the global climate change. The indirect effect of aerosols is their impact on the size and number of cloud droplets. A second indirect effect of aerosols on clouds, namely their effect on cloud lifetime also lead to a negative temperature forcing. Establishing aerosol particle sources is an important task. One of the methods which allows “fingerprinting” carbon origin in aerosol particles is measurement of the carbon isotope ratio. Discrimination among isotopes occurs in internal combustion engines due incomplete combustion. Fuel and combustion products (CO2, aerosol particles) have a different isotopic signature. For determination anthropogenic carbon part in aerosol particles it is necessary to know what changes in the isotope ratio occur during combustion. In our study we used petrol, diesel and gas driven vehicles to generate aerosol particles. The aerosol particle carbon isotopic signature differs depending on the fuel used and presence of a catalytic converter in a car. We have shown that in internal combustion engines generated aerosol particles the carbon isotope ratio is overlapping with particles of natural origin and solely cannot be used for estimating carbon amount from fossil fuel combustion. Combination of stable and radioactive carbon isotope ratio measurements would be a promising tool for aerosols sources characterization.