Nanoaerosols including radon decay products in outdoor and indoor air at a suburban site.

Mateja Smerajec,Janja Vaupotič

doi:10.1155/2012/510876

Mateja Smerajec, Janja Vaupotič

Open Access

https://doi.org/10.1155/2012/510876

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Abstract

Nanoaerosols have been monitored inside a kitchen and in the courtyard of a suburban farmhouse. Total number concentration and number size distribution (5–1000 nm) of general aerosol particles, as measured with a Grimm Aerosol SMPS+C 5.400 instrument outdoors, were mainly influenced by solar radiation and use of farming equipment, while, indoors, they were drastically changed by human activity in the kitchen. In contrast, activity concentrations of the short-lived radon decay products 218Po, 214Pb, and 214Bi, both those attached to aerosol particles and those not attached, measured with a Sarad EQF3020-2 device, did not appear to be dependent on these activities, except on opening and closing of the kitchen window. Neither did a large increase in concentration of aerosol particles smaller than 10 or 20 nm, with which the unattached radon products are associated, augment the fraction of the unattached decay products significantly.

Highlights

Air is an aerosol with suspended particulate matter
The particle size ranges from several nm for molecular clusters to about 100 μm for fog droplets and dust particles
The particle size, structure, and chemical composition of aerosols are of key importance for climate and environmental health and are of great interest to aerosol scientists, atmospheric chemists and physicists, and toxicologists and are of serious concern to the regulatory bodies responsible for public health

Summary

Introduction

Air is an aerosol with suspended particulate matter. The particle size ranges from several nm for molecular clusters to about 100 μm for fog droplets and dust particles. Radon travels through the medium either by diffusion or, more effectively and over longer distances, carried by gas or water [20] On its way, it accumulates in underground rooms (mines, karst caves, fissures, basements) and eventually enters the atmosphere and appears in the air of living and working environments. Birchall et al [38, 39] elaborated the procedure for calculating dose conversion factor (DCF-D ), which is used mainly for research purposes They showed that the parameter most affecting DCF-D , and the calculated effective dose, is the fraction ( f un ) of the unattached RnDP, defined as [19]. Knowledge of the number concentration and size distribution of aerosol particles, to which RnDP are associated, is a prerequisite to better understanding the f un values and their temporal variation in an environment [50]. In the present paper, monitoring of nano-aerosols including radon decay products in outdoor and indoor air at a suburban site is described, and results are presented and commented on

Measuring Techniques

Results and Discussion

Conclusion