Anticipating one of the worst ozone densities in years, South Korea's Environment Ministry has put forth a list of measures to reduce the pollutant, which is largely due to nitrogen oxides and other volatile organic compounds (VOC) emitted from cars and aerosol spray cans. The ministry said that an ozone alert was issued 35 times over the 14 days leading up to Aug. 13. It expects this year's levels exceed last year's, when the alert had been issued 38 times over the entire year.