Black smoke as a surrogate for PM10 in health studies?

There is a rapidly growing interest in health implications of airborne fine particles. The focus of attention is on particulate matter less than 10 μm aerodynamic diameter (PM10). In the U.K. there are few PM10 measurements and this is potentially hampering health effect studies. There is however a wide body of black smoke data using the British Standard smoke stain method. Black smoke may indeed be a better indicator of health impacts. It is therefore timely to examine the relationship between black smoke and PM10. This has been done using recent monitoring results for Bristol, a moderate sized U.K. city. Daily average black smoke (averaged over six urban background sites) is shown to be a reasonable predictor of daily average PM10 and of daily peak 1 h PM10. However, different relationships apply to winter and summer periods showing that these methods are measuring different components of fine airborne particles.