Fine particle mass, number, surface, area concentration metrics and their correlation in outdoor environments
Exposure to fine particles is measured using metrics such as mass concentration (MC), number concentration (NC) and surface area concentration (SAC). This study aims to find correlation between the three metrics in outdoor environments of a city – city periphery, city centre and on-road. Simultaneous real-time mass, number and surface area concentration measurements were conducted in these environments. Arithmetic means, peak concentration values, and regression coefficients were determined to find relation between the three metrics. Results indicate remarkable high indoor number, mass and surface area concentrations. For ambient sampling sites, good correlation coefficient r2 = 0.80 between MC and NC, and r2 = 0.69 between NC and SAC metrics were observed. However, traffic-influenced on-road measurements showed little weaker correlations of r2 = 0.45 and r2 = 0.30 respectively.