Influence of Traffic on the PM sub(10) and PM sub(2.5) Urban Aerosol Fractions in Madrid (Spain)

Data from the air-quality network in Madrid, Spain, were used to analyze the average PM sub(10) values and their seasonal evolution. The data pertained to the chemical composition of PM sub(10) and PM sub(2.5) fractions sampled during a study conducted at a representative traffic-influenced site. Results showed that PM sub(10) and nitrogen dioxide, which was used as an indicator of traffic emissions, displayed different seasonal patterns, with NO sub(2) concentrations decreasing in spring summer and PM sub(10) concentrations being relatively evenly distributed throughout the year. The major component of the PM fractions was non-mineral carbon generated by combustion processes, while crustal components were found mostly in the PM sub(10) fraction. The most-abundant heavy metal present in both fractions was lead. Traffic emissions appeared to concentrate mostly on the finer fraction.