Behavior of total peroxy and total organic nitrate concentrations at Suzu on the Noto Peninsula, Japan: Long-range transport and local photochemical production

Abstract

We performed continuous observations (2012–2015) of total peroxy nitrates (PNs) and total organic nitrates (ONs) at Suzu on the Noto peninsula, Japan. It was found that PNs and ONs showed similar seasonal variations with maximum concentrations in spring and minimum concentrations in summer. Concentrations of PNs and ONs were high for air masses originating from the Asian continent from winter to spring, whereas they were independent of air mass origin from spring to summer. In summer, PNs and ONs indicated similar diurnal variations with maximum concentrations during daytime and minimum concentrations during nighttime. Such diurnal variations of PNs and ONs were small in winter. Diurnal variations of PNs in spring were similar to those in summer, whereas such diurnal variations were not observed for ONs in spring. In the cold season, PNs and ONs have long atmospheric lifetimes and local photochemical production rates of PNs and ONs are slow, whereas the converse is true in the warm season. Therefore, concentration variations of PNs and ONs are governed primarily by long-range transport in the cold season and by local photochemical production in the warm season.