Evolution of Ozone & Carbon Monoxide over the North Atlantic

Tropospheric ozone (O3) and carbon monoxide (CO) are important air pollutants and are affected by anthropogenic emissions. The relatively long atmospheric lifetimes of O3 and CO enable them to be transported over long distances from source to receptor regions. There have been significant emission reductions in North America and Europe for the past decade while the emissions from Asia have increased for the same period, with contrasting implications for the intercontinental transport of O3 and CO. In-situ measurements of O3 and CO for the period of 2001-2011 at the remote Pico mountain observatory located in the North Atlantic are analyzed and combined with global atmospheric chemical transport model simulations to examine the evolution of tropospheric O3 and CO over the North Atlantic for this period. Possible trends in tropospheric O3 and CO over the North Atlantic are identified with statistical analysis and the contributions from various source regions are calculated with extensive model simulations.