Classification, analysis and interaction of solid airborne particles in urban environments

An analysis was made of airborne solid particulate matter in Córdoba, a city in the southwestern Iberian Peninsula with a Mediterranean climate. The detection and analysis techniques used enabled solid particles to be classified by size, by biogenic or non-biogenic origin, and by natural source of emission, e.g. pollen grains released by vascular plants during the pollen season, or particles attributable to human activity. Airborne particles of biogenic origin were predominant in the spectrum of the air in Córdoba. Intradiurnal variations in solid-particle counts closely reflected human activities, especially traffic. Peak biogenic-particle counts at times coincided with peak non-biogenic particle counts, suggesting that in certain weather conditions, particulate matter is not dispersed due to the high degree of atmospheric stability, and also that there may be interactions between the two types of particle, mediated by the presence of very small allergenic particles. This joint action may prompt a worsening of symptoms in pollen-allergy sufferers, as well as a deterioration in biological air quality.