Three-dimensional air quality simulation study on low-emission vehicles in Southern California

The effect of low-emission vehicles on improving air quality in Southern California was analyzed using a three-dimensional simulation model. Simulations were performed using 1987 emission data and meteorological data released by the California Air Resources Board. Exhaust emission data at TLEV, LEV and ZEV levels were used in the analysis. The results show that a reduction in reactive organic gases (ROG) has a large effect on reducing the ozone concentration. The ozone reduction effects of alternative fuels like methanol or compressed natural gas can also be analyzed at the same stage as exhaust emissions from conventional gasoline vehicles by applying the maximum incremental reactivity index to correct measured ROG data. The ROG/NOx ratio at the time of peak ozone concentration correlates well with the ozone level, suggesting that a reduction in NOx emissions does not always lower the ozone concentration.