Increased lung deposition of charged particles

There has been much concern about the health effects of air pollution, with particular interest in the nano-aerosols, size range 20 � 200 nm. In this size range, lung deposition on inhalation can be as low as 30%. High voltage powerlines frequently emit corona ions which can attach to these pollutant aerosols, thereby increasing their charge state. The addition of such electric charge increases the likelihood of lung deposition of inhaled aerosols by mirror charge effects. A mechanical lung has been developed to measure deposition of environmental particles. The initial aim is to measure the deposition of aerosols in the lung model near powerlines where significant corona ion emission is present. This should serve to investigate the effect of electric charge on deposition in the lung in an outdoor atmosphere.

The mechanical model is based on Weibel�s (1963) symmetric adult lung model. The first four branches of the bronchial tree are made from metal piping at the correct size and branching angle. After the fourth generation, which has 128 tubes, this technique is no longer a viable engineering option and the lower generations are represented by wire meshes. Sample air is drawn either through the lung or through the control tube into a TSI 3010 condensation particle counter.

The model is portable and it is intended to measure deposition upwind and downwind of high voltage powerlines. The measurements will be carried out in a variety of weather conditions, in both urban and rural environments. These then could be extended to other sources of charged aerosols in the atmosphere, including vehicle exhaust emissions.

Click here for a more detailed description of the lung model and the latest experimental results.