We have assessed the physical and dynamic characteristics of 23 home jet nebulizer/compressor combinations currently available in the UK and Europe. The combinations were evaluated in terms of pressure-flow characteristics, aerosol mass distribution, volume output, electrical costs, and sound level. In addition, we determined the effect of nebulizer fill volume on aerosol mass distribution and volume output. One nebulizer was used with six different compressors, and four compressors were tested with three different nebulizers. The pressure-flow relationships showed a wide variation between models, as did flow-rate at the nebulizer (range 3.0-8.0 L.min-1). The mean +/- SD volume nebulized after 10 min using an initial fill volume of 2.5 and 5.0 mL was 46 +/- 9 and 34 +/- 12%, respectively. The mass median aerodynamic diameter (MMAD) over a 5 min nebulization ranged 2.6 to 10.2 microns. Nine of the nebulizations produced an MMAD of less than 5 microns at both fill volumes. Changing nebulizer/compressor combinations affected flow rate, MMAD and volume output. Sound levels varied between models. Running costs were low, with all using less than 74 kilowatt hours of energy per year. We conclude that there is a wide variation in performance of nebulizer/compressor combinations for use with nebulized bronchodilators. Correct matching of the nebulizer/compressor is seen to be important to ensure optimum performance.(ABSTRACT TRUNCATED AT 250 WORDS)