Characterization of the concentration and distribution of urban submicron (PM1) aerosol particles

Concentrations of ambient particulate matter mass were measured in terms of PM1 and PM1–10 for 8 months between 2000 and 2001, at a sampling site in the urban area of the city Kaohsiung, Taiwan. The data from 20 samples were closely studied for any seasonal phenomena that affected air pollution patterns. The PM1 and PM1–10 concentration variations differed in the examined patterns. This seemed to indicate that the ambient coarse (PM1–10) and submicron (PM1) particles were being contributed by different sources. On average for the 8-month samples, 52±20% of the PM10 was made up of PM1. The PM1-to-PM10 ratio was observed to vary between summer and winter, it being higher in the summer (approximately 62% in summer and 48% in winter). The correlation (r2) between the PM1/PM10 ratio and the parameters showed that there was no significant correlation between the PM1/PM10 ratio, PM concentrations, and the average and maximum wind speeds. Both emission activities and meteorological conditions are important when considering airborne pollutant concentrations. Based on the evaluation of the data obtained in this study, the contribution to the concentration level of the PM and the ratio at the sampling site could have depended upon meteorological parameters and also the formation of PM, i.e. the formation of secondary aerosols. Results from recent studies (J. Air Waste Manage. Assoc. 51 (2001) 489; Atmos. Environ. 36 (2002) 1911) at this same study site supported that combustion sources and secondary aerosols played significant roles in the formation of ambient submicron (PM1) aerosol particles in the urban area.