In view of this, in this paper we examine satellite measurements of tropospheric
ozone, carbon monoxide (CO) and NO2on a global scale, to identify the area sources,
seasonal variation and long-range transport of air pollutants in the northern and
southern hemisphere. In recent decades a number of satellite sensors have started to
measure composition in the troposphere. Here, we have used the satellite-borne
tropospheric ozone measurements obtained from the tropospheric ozone residual
(TOR) method (Fishman et al. 2003), CO measurements from MOPITT and NO2
measurements from SCIAMACHY for the three-year period 2003–2005, which pro-
vide the information on a global scale.