The application of forest classification from Landsat data as a basis for natural hydrocarbon emission estimation and photochemical oxidant model simulations in southeastern Virginia

The possible contribution by natural hydrocarbon emissions to the total ozone budget recorded in the tidewater region of southeastern Virginia during the height of the summer period was examined. Natural sources investigated were limited to the primary HC emitters and most prevalent natural vegetation, the forests. Three forest types and their areal coverage were determine for Region VI of the Virgina State Air Pollution Control Board using remotely sensed data from Landsat, a NASA experimental earth resources satellite. Emission factors appropriate to the specific types (coniferous 0.24 x 10/sup 13/, mixed 0.63 x 10/sup 13/, deciduous 1.92 x 10/sup 13/ ..mu..g/h), derived from contemporary procedures, were applied to produce an overall regional emission rate of 2.79 x 10/sup 13/ ..mu..g/h for natural non-methane hydrocarbons (NMHC). This rate was used with estimates of the anthropogenic NO/sub x/ and NMHC loading, as input into a photochemical box model. Additional HC loading on the order of that estimated to be produced by the natural forest communities was required in order to reach certain measured summer peak ozone levels as the computer simulation was unable to account for these measured episodic levels on the basis of the anthropogenic inventory alone.