Hydrogen peroxide in air during winter over the south‐central United States

Hydrogen peroxide and other atmospheric trace gases were measured along the 91°30′ meridian from near the Iowa border to the Gulf of Mexico during February 1987. The measured H 2 O 2 values were within the range of <0.1 to 1.0 ppbv and an increase in concentration from north to south of 0.04‐0.05 ppbv per degree of latitude was observed on five of six flights. The concentration of H 2 O 2 appeared to be primarily dependent upon air mass history; concentration discontinuities were observed when the aircraft flew across air mass boundaries. H 2 O 2 measurements during flights in air masses of similar histories during daylight and night showed no significant difference in concentration. Neither was there a consistent dependence of the H 2 O 2 concentration upon altitude.