Multi-angle absorption photometry—a new method for the measurement of aerosol light absorption and atmospheric black carbon

Contribution from indoor sources to particle number and mass concentrations in residential houses

Transmission electron microscopical and aerosol dynamical characterization of soot aerosols

Humans and their activities are known to generate considerable amounts of particulate matter indoors. Some of the activities are cooking, smoking and cleaning. In this study 13 different particle sources were for the first time examined in a 32 m3 full-scale chamber with an air change rate of 1.7 ± 0.1/h. Two different instruments, a condensation particle counter (CPC) and an optical particle counter (OPC) were used to quantitatively determine ultrafine and fine particle emissions, respectively. The CPC measures particles from 0.02 μm to larger than 1.0 μm. The OPC was adjusted to measure particle concentrations in eight fractions between 0.3 and 1.0 μm. The sources were cigarette side-stream smoke, pure wax candles, scented candles, a vacuum cleaner, an air-freshener spray, a flat iron (with and without steam) on a cotton sheet, electric radiators, an electric stove, a gas stove, and frying meat. The cigarette burning, frying meat, air freshener spray and gas stove showed a particle size distribution that changed over time towards larger particles. In most of the experiments the maximum concentration was reached within a few minutes. Typically, the increase of the particle concentration immediately after activation of the source was more rapid than the decay of the concentration observed after deactivation of the source. The highest observed concentration of ultrafine particles was approximately 241,000 particles/cm 3 and originated from the combustion of pure wax candles. The weakest generation of ultrafine particles (1.17 × 107 particles per second) was observed when ironing without steam on a cotton sheet, which resulted in a concentration of 550 particles/cm3 in the chamber air. The highest generation rate (1.47 × 1010 particles per second) was observed in the radiator test.

Characterization of indoor sources of fine and ultrafine particles: a study conducted in a full-scale chamber.

The interaction of ozone and water vapor with spark discharge soot particles coated with the five-ring polycyclic aromatic hydrocarbon benzo[a]pyrene (BaP) has been investigated in aerosol flow tube experiments at ambient temperature and pressure (296 K, 1 atm). The investigated range of ozone volume mixing ratio (VMR) and relative humidity (RH) was 0−1 ppm and 0−25%, respectively. The observed gas-phase ozone losses and pseudo-first-order BaP decay rate coefficients exhibited Langmuir-type dependencies on gas-phase ozone concentration and were reduced in the presence of water vapor, which indicates rapid, reversible and competitive adsorption of O3 and H2O on the particles followed by a slower surface reaction between adsorbed O3 and BaP. At low ozone VMR and RH, the half-life of surface BaP molecules was found to be shorter than previously reported (∼ 5 min at 30 ppb O3 under dry conditions). At higher RH and for multilayer BaP surface coverage, however, a strong increase of BaP half-life was observed a...

Interaction of Ozone and Water Vapor with Spark Discharge Soot Aerosol Particles Coated with Benzo[a]pyrene: O3 and H2O Adsorption, Benzo[a]pyrene Degradation, and Atmospheric Implications

C. Wadenpohl

Papers

Investigations of a new aerosol generator for the production of carbon aggregate particles