CO residence times on urban roads in the Naples area using air quality monitoring data

Typical day patterns of CO measured at four different stations in the Naples urban area were studied in order to evaluate the average residence time of passive vehicular pollutants on urban roads. The mass balance equation was written under the assumption that each road would act as a completely mixed volume. Average hourly concentration data of CO measured between 0:00 and 5:00 a.m. on working days (Monday–Friday) from 1/1/2001 to 31/12/2002 were regressed with the model equation. Average residence time is in the range 2.5–4.4 h.