Table 1.

Data coverage at the measurement sites for each sensor system. Number of hours with valid hourly averaged sensor output as a percentage of the total number of hours in the measurement period (one year).

Station/Sensor No.	%
Botlek 01	91
Botlek 02	55
Veldhoven 03	59
Veldhoven 04	54
Breukelen 05	38
Breukelen 06	78
Utrecht 07	100
Utrecht 08	71
Average	68