Abstract:On the basis of data collected at Lin′an station during October/early November,we analyze the ozone and its precursor′s (NOx*,CO,NMHC) characteristics and their relations to meteorological parameters.CO and NOx* levels are related closely to macroscale synoptic system.On account of abundant ozone precursors at Lin′an station, the high O3 will occur on a sunshine day.The aromatic is the largest part of NMHCs by carbon atom concentration,followed by alkane,alkene,alkyne and biogenic hydrocarbons.As a case study,we simulate photochemical ozone production rate P(O3),depletion rate L(O3) and the relative contributions of chemical reactions to ozone genesis/lysis by an observation-based photochemical box model.The results show that P(O3) is one order of magnitude larger than L(O3) in a clear autumn day of Lin′an.The net ozone production rate can reach up to 14.8×10-9h-1 in the noontime.The sensitive experiments reveal that Lin′an net photochemical ozone production rate is highly sensitive to NMHCs.