Influence of an enhanced traffic volume around beaches in the short period of summer on ozone

The impact of pollutant emissions by the significant amount of road traffic around beaches on the ozone (O3) concentrations in the surrounding regions were evaluated using a numerical modeling approach during 6 days (29 July through 3 August) of the beach opening period (BOP) in 2010. On-road mobile emissions at several roads close to beaches in Busan, Korea during the study period were estimated from the emission factors, vehicle kilometers traveled, and deterioration factors. The emission data was then applied to the 3-D chemical transport model. A process analysis (PA) was also used to assess the contributions of the individual physical and chemical processes to the production or loss of O3 in the study area. The model study suggested the possibility that road traffic emissions near the beach area can have a significant impact on the O3 concentrations in the source regions as well as their surrounding/downwind regions. The maximum negative impact of mobile emissions on the O3 concentrations was predicted near the beach areas: by −9 ppb during the day due to both the high NOx emissions with the high NOx/VOC ratio and meteorological conditions and −9 ppb at night due to the fast titration of O3 by NO. The PA showed that the contribution of chemical process to the decrease in O3 concentrations (up to −5.5 ppb h−1) due to mobile emissions near the beach areas was the most dominant compared to the other physical processes.