Diesel and wood combustion are major sources of carbonaceous particles in the atmosphere. It is very hard to distinguish between the two sources by looking at soot particle morphology, but clear differences in the chemical structure of single particles are revealed by C(1s) NEXAFS (near edge X-ray absorption fine structure) microspectroscopy. Soot from diesel combustion has a dominant spectral ...

Recently, particulate matter from diesel engines has become an important topic in environmental, scientific, and political discussions. European legislation on particulate matter (PM) emissions has made significant advancement with the adoption of limit value standards up to and including Euro IV for heavy-duty (HD) engines. Efforts to reduce soot particulate from automotive engine exhaust have...

Soot sensors are required for on-board diagnostics (OBD) of automotive diesel particulate filters (DPF) to detect filter failures. Widely used for this purpose are conductometric sensors, measuring an electrical current or resistance between two electrodes. Soot particles deposit on the electrodes, which leads to an increase in current or decrease in resistance. If installed upstream of a DPF, ...

The particle size distribution plays an important role in environmental pollution detection and human health protection, such as fog, haze, and soot. In this study, the attractive and repulsive particle swarm optimization algorithm and the basic particle swarm optimization were applied to retrieve the particle size distribution. The spectral extinction technique coupled with the anomalous diffr...

A major source of particle number emissions is road traffic. However, scientific knowledge concerning secondary particle formation and growth of ultrafine particles within vehicle exhaust plumes is still very limited. Volatile nanoparticle formation and subsequent growth conditions were analyzed here to gain a better understanding of "real-world" dilution conditions. Coupled computational fluid...

Laser interaction with nanoscale particles is distinct and different from laser-bulk material interaction, where a hot plasma is normally created. Here, we review our studies on 193 nm laser ablation of various nanoscale particles including NaCl, soot, polystyrene, and gold. The 20 ns laser beam with fluences up to 0.3 J/cm irradiates nanoparticles in a gas stream at laser repetition rates from...

Soot formation was studied within laminar premixed ethylene/air flames (C/O ratios of 0.78-0.98) stabilized on a flat-flame burner operating at atmospheric pressure. Measurements included soot volume fractions by both laser extinction and gravimetric methods, temperatures by multiline emission, soot structure by thermophoretic sampling and transmission electron microscopy, major gas species con...

A sooting, ethylene coflow diffusion flame has been studied both experimentally and computationally. The fuel is diluted with nitrogen and the flame is slightly lifted to minimize the effects of the burner. Both probe (thermocouple and gas-sampling techniques) and optical diagnostic methods (Rayleigh scattering and laser-induced incandescence) are used to measure the temperature, gas species, a...

To calculate soot source terms a new detailed kinetic soot model is applied to study the formation and oxidation of soot particles in turbulent flames. The model is based on a detailed description of the chemical and physical processes leading to the formation of soot. It can be subdivided into the growth of polycyclic aromatic hydrocarbons (PAHs) in the gas phase reactions and the processes of...

The role of soot and volatile aerosol in controlling ice particle formation in cirrus clouds is of global importance for climate. In particular, contrail studies may help to better understand the role of various aerosols in ice formation. Recent results suggest that contrails may contribute a large share to the climate impact of aviation. Hence, better knowledge on contrails is needed for devel...