Tropospheric ozone and nitrogen dioxide measurements in urban and rural regions as seen by IASI and GOME‐2

Tropospheric ozone (O 3 ) columns in urban and rural regions as seen by the Infrared Atmospheric Sounding Interferometer (IASI) are analyzed along with the Global Ozone Monitoring Experiment (GOME‐2) tropospheric nitrogen dioxide (NO 2 ) columns. Results over nine cities of the Northern Hemisphere for the period 2008–2011 show a typical seasonal behavior of tropospheric O 3 , with a first maximum reached in late spring because of stratospheric intrusion mainly and a continuous rise till the summer because of the anthropogenic‐based ozone production. Over the East Asian cities, a decrease in the O 3 tropospheric column is detected during the monsoon period. Seasonal cycling of tropospheric NO 2 shows consistent higher values during winter because of the higher anthropogenic sources and longer lifetime. In rural regions, a complex relation between the O 3 and NO 2 columns is found, with good correlation in summer and winter. O 3 concentrations in rural sites are found to be comparable to those closest to the anthropogenic emission sources, with peak values in spring and summer. Furthermore, the effect of the reduction of pollutant emissions in the Beijing region during the Olympic Games of 2008 compared to the same summer period in the following 3 years is studied. GOME‐2 NO 2 measurements show a reduction up to 54% above Beijing during this period compared to the following 3 years. IASI O 3 measurements show an increase of 12% during July 2008 followed by a decrease of 5–6% during the months of August and September.