A photochemical/diffusion simulation model is employed to evaluate four control strategies for reducing air pollution in Los Angeles. Three previously tested, representative air trajectories serve as baseline cases using 1969 emission levels. Transportation controls are emulated by reducing source emissions in accordance with hypothetical plans worked out with the Division of Meteorology of the Environmental Protection Agency. Straight reductions of vehicle miles traveled do not give ozone reduction percentages that are as large as the emission reduction percentages. Strong influence of initial pollutant load of the air in the morning is noted. Day-to-day pollution carryover must be carefully adjusted through the initial conditions to account for continous strategies in contrast with intermittent strategies. Ratios of nitrogen oxides to reactive hydrocarbon affect the ozone buildup markedly. It is found that control of the mixture ratio can be more important than straight reduction in emissions. (Author)