Investigation of geographical and temporal distribution of tropospheric ozone in Catalonia (North-East Spain) during the period 2000–2004 using multivariate data analysis methods

Multivariate data analysis methods were applied to study the geographical and temporal distribution of tropospheric ozone in Catalonia (North-East Spain). Ozone data were collected during the period 2000–2004 in 41 sampling stations. Data analysis by multivariate curve resolution alternating least squares (MCR-ALS) allowed the recognition of three sub-regions within Catalonia according to their ozone variation patterns. Representation of loadings by means of geographical information systems (GIS) allowed a better visualisation of these areas. Daily, weekly and annual ozone profiles were determined for each sub-region. Principal component analysis (PCA) was applied within each sub-region to unravel the relationship between ozone variation and some other parameters, such as atmospheric pollutants (SO2, H2S, NO, NO2, CO and particulate matter), as well as meteorological variables (temperature, relative humidity, solar radiation, pressure, precipitation and wind speed).