Ch3ooh ch2o hcooh ch3cooh so2

SO4 and CRESOL are assumed to be 5 days (Logan et al., 1981). Results of the layer of 16 m height, at which most surface measurements were made, are used to make a comparison with measurements at surface stations and the OBM results.

The emission rates of O3 precursors are based on the Taiwan Emission Data System (TEDS 5.0, 2000) published by the TEPA ( Area and line sources in the KaoPing area are averaged to obtain the average emission rates. The emission rates of NOx, CO and SO2 are calculated to be 3.4 • 1016, 5.0 • 1016 and 3.0 • 1015 molecules m-2 s-1, respectively. The emission rates of ethane, propane, butane, ethane, propene and toluene are assumed to be 3.4 • 1015, 2.5 • 1015, 2.7 • 1015, 5.9 • 1015, 8.4 • 1015 and 2.6 • 1015 molecules m~2 s_1, respectively. The iso-prene emission rate is fixed at 3.6 • 1015 molecules m~2 s_1. The solar zenith angle is set to be that of September 30, at 22.5°N. A few weeks' difference in the zenith angle is negligible for photodissociation rates. The photodissociation rate constants are generated by the Tro-pospheric Ultra-Violet (TUV) radiation model (TUV 4.2; Madronich and Flocke, 1998). The climatological values of total ozone observed by the Brewer ozone meter at Chengkung station (121.3°E, 23.1°N, close to the latitude of northern Kaohsiung County) and an aerosol optical depth of 0.4 at 550 nm are used. The model calculation is carried out for 3 days to reach a quasi-steady state condition. Atmospheric concentrations at 11 a.m.-12 noon of the day 4 simulation are used to make a comparision with the OBM results.

2.3. Observation-based method/model

Following the approach developed by Liu et al. (1987) and Trainer et al. (2000), the net production rate of O3, P(Ox), can be expressed as

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