Search results

The aim of the paper is to present the results of investigations of fine particle generation by small biomass combustion and the possibility of reducing the emissions by electrostatic precipitation.

The grains, wood‐logs, wood‐, mixed‐ and straw‐pellets were combusted in two stoves and two boilers. The set‐ups were operated according to DIN‐4702. Particle number concentration in the gas flow was measured by Scanning Mobility Particle Sizer and particle mass concentration was measured according to the Guidelines VDI‐2066 upstream and downstream a novel space charge electrostatic precipitator (ESP). The ESP consists of an ioniser and a grounded brush inside of a tube form grounded collector electrode.

The ESP ensures stable operation at gas temperatures up to 350°C. The use of sharp‐points high voltage electrode ensures effective particle charging at high particle number concentrations. The combustion of wood‐pellets is characterized by lower particle mass concentrations. The highest particle mass concentrations were observed by the straw‐pellets combustion. The ESP ensures particle collection with mass collection efficiency 87±3% for wood‐logs and 82±2% for wood‐pellets combustion.

The novel ESP is recommended for exhaust gas cleaning from small scale biomass combustion facilities and domestic heating units. The use of the ESP would reduce the emissions of fine aerosol into the atmosphere and improve the air quality.

The paper presents the comparative analysis of particle size distribution and particle mass concentrations in the exhaust gas from small‐scale combustion units for different types of biomass. The study confirms the possibility to reduce particle emissions by electrostatic precipitation. The originality of the technology and apparatus is patently protected.

The purpose of this paper is to investigate competitive effect of source strength and coagulation on the evolution of aerosol size distribution with a continuous source.

A theoretical model was proposed in which the nanoparticle population balance equation with respect to particle size was solved by the sectional method.

It was found two modes appear when a nanoparticle system was injected by a continuous source.

Through tracing the evolution of particle size distribution with different source strength, the characteristics of two modes as well as their lag-time to approach steady state were deeply investigated.

Describes the development and application of an aerosol model for regional air quality simulations. The aerosol model MADE is based on a modal concept and describes the chemical composition and the size distribution of atmospheric particulate matter. Primary as well as secondary aerosol components are considered in the model, which is fully integrated into the photochemical transport model EURAD. The model system has been applied to a European domain with different resolutions, using a one‐way nesting procedure. Simulations show the potential importance of secondary organics of anthropogenic and biogenic origin for the tropospheric particle loading. In addition it is shown that a reduction in precursor emissions for the inorganic ion fraction of PM (sulphate, nitrate and ammonium) does not necessarily lead to an equivalent reduction in PM2.5 mass concentrations, as for example a reduction in sulphate aerosol caused by reduced SO₂ emissions might be compensated by enhanced formation of nitrate aerosols in certain regions.

The purpose of this paper is to discuss the light scattering of nonspherical particles that is very important for the research on the aerosol optical properties.

In this paper, the authors use the spheroid model as the characteristic particle shape to study the single scattering albedo of real nonspherical particles. Meanwhile, the extinction and scattering cross section of spheroids are calculated with the T matrix method combined with the improved geometric optics approximation method (IGOM).

Through this combination, the extinction and scattering cross section of spheroids can be obtained in the larger size range and aspect ratio range. Furthermore, the comparison of the single scattering albedo for the spheroids and their equivalent spheres is conducted in order to investigate the difference of the spherical and nonspherical particles.

Simulation experiments indicate that the single scattering albedo of spheroids can be calculated well with this combination, and it has some obvious influence on the variation of the aspect ratio, incident wavelength, and complex refractive index of spheroid particles.

A multi wavelength optical sensing technique has been tested for monitoring a smoke or aerosol polydispersion so as to allow positive discrimination between types of aerosols or particles. It uses a polychromatic LED and spectral analysis in real‐time via the technique of chromatic modulation which allows a three‐parameter description to characterise spectral interactions due to scattering.

Among others, the resuspension of fine and ultrafine particulate matters (PMs) on air due by land take effect is an uncovered issue. The relation between land use change and fluxes of PM is not systematically observed even if the common classification of ecosystem services (ESs) clearly shows relationship between soil and aerosol concentrations. Soil does not act only as carbon pool, but it is also a crucial variable for the resuspension dynamic of particulates. If key policies of sustainable urban development is focused on “quality of life,” it is necessary to map and evaluate the effect of land take on airborne fluxes in metropolitan areas. The paper aims to discuss these issues.

The paper allows to introduce pioneer studies on air quality in large urban areas outling a methodology of particulate field measurement. It introduces newer quantitative/qualitative assessment of environmental effect due to urbanization ensuring a major efficiency on ES degradation.

Expected results are the estimation of resuspension dynamics of aerosol for typical land cover pattern.

Implications are mainly destinated to increase significant knowledge and general awareness of the environmental effect caused by urban growth: urban areas act as a hotspot for health risk as both particle sources and human population are concentrated in these areas.

Considering that cardiovascular diseases are significantly caused by air quality, the paper aims to support sustainable planning policies aimed to achieve a better quality of environment on urban areas.

Aerosols play an important role in the radiative balance of the atmosphere. While sulphate aerosols are recognized as the dominant contributor of tropospheric aerosols over and near industrialized regions, smoke aerosols containing soot or elemental carbon are regarded with increasing importance on a global basis. The fate of carbonaceous aerosols is at present poorly understood as a result of various atmospheric processes. This paper examines the effect of morphology on the physical and chemical properties of atmospheric aerosols, in the context of fractal theory. The use of a fractal dimension to describe aggregate morphology enables more accurate modelling of sedimentation and optical characteristics.

The purpose of this paper is to study the soot formation and evolution by using this newly developed Lagrangian particle tracking with weighted fraction Monte Carlo (LPT-WFMC) method.

The weighted soot particles are used in this MC framework and is tracked using Lagrangian approach. A detailed soot model based on the LPT-WFMC method is used to study the soot formation and evolution in ethylene laminar premixed flames.

The LPT-WFMC method is validated by both experimental and numerical results of the direct simulation Monte Carlo (DSMC) and Multi-Monte Carlo (MMC) methods. Compared with DSMC and MMC methods, the stochastic error analysis shows this new LPT-WFMC method could further extend the particle size distributions (PSDs) and improve the accuracy for predicting soot PSDs at larger particle size regime.

Compared with conventional weighted particle schemes, the weight distributions in LPT-WFMC method are adjustable by adopting different fraction functions. As a result, the number of numerical soot particles in each size interval could be also adjustable. The stochastic error of PSDs in larger particle size regime can also be minimized by increasing the number of numerical soot particles at larger size interval.

In this paper, a light-weight, low-power atmospheric multi-parameter sensor (AMPS), which could be mounted on small flying platforms such as a tethered balloon, a quad-rotor unmanned aerial vehicle (UAV), a UAV helicopter, etc., is implemented and integrated to sample vertical distribution of aerosols with integrated parameters of aerosol particle concentration, temperature, relative humidity and atmospheric pressure.

The AMPS integrates three kinds of probes in an embedded system. A synchronous method based on GPS is proposed to drive the laser aerosol particle sensor, the temperature and humidity probe and the pressure probe to sample four channels approximately simultaneously. Different kinds of housing are designed to accommodate various flying platforms, and the weight is controlled to adapt the payload of each platform.

A series of validation tests show that while the AMPS achieves high precision, its power consumption is less than 1.3 W, which is essential for light flying platforms. The AMPS was mounted on different flying platforms and the difference was evaluated. For three times every five days, vertical profiles of PM2.5 and PM10 concentrations were observed by the AMPS mounted on a quad-rotor UAV, which revealed the significant correlation between the aerosol particle concentration and atmospheric parameters.

A new light-weight and low-power AMPS for small flying platforms is designed and tested, which provides an effective way to explore the properties of aerosol vertical distribution, and to monitor pollutants flexibly.