Sensitivity of ozone production to increasing temperature and reduction of precursors estimated from observation data

Abstract

The sensitivity of ozone production to increasing temperature and a decreasing concentration of precursors, namely nitrogen oxides and non-methane hydrocarbon, has been estimated with probability theory using observation data for 2004–2015 for the Kanto region, Japan. The sensitivity of ozone, in terms of the number of high ozone concentration days, to temperature was higher at the beginning of the observation period when precursor concentrations were high but lower in more recent years when the precursor concentrations were lower. Analysis of the high ozone concentration days showed that a 10-percent reduction of both precursor concentrations yields a reduction in the number of high concentration ozone days of approximately 4 days per year, whereas a 0.2 °C temperature increase leads to less than a 1-day increase per year. This indicates that precursor concentration is more important than temperature for determining ozone concentration.