We present a regional analysis of CH3OH and (CH3)2CO in the New England continental and coastal marine atmospheres. Vegetative emissions over land comprise 60–80% of the daily peak-to-peak differences in the diurnal cycles of these oxygenated hydrocarbons. In the morning downward mixing of remnant boundary layer air over land provides an additional source equal to more than half of the vegetative emission strength. The ocean is both a sink and a source of CH3OH and (CH3)2CO, with dry depositional losses 2-fold greater than their source counterparts of 0.35 and 0.17 ppbv d−1 respectively. Anthropogenic emissions compensate for 59% and 52% of CH3OH and (CH3)2CO oceanic sink respectively, whereas over land this source is relatively small compared to substantial vegetative sources. Direct measurements of ocean- and land-air fluxes of CH3OH and (CH3)2CO and boundary layer height are needed to better constrain their regional budgets.