Light-duty passenger cars and large ocean-going vessels represent two particle emission sources that have the ability to affect human health, climate change and air quality in local communities and worldwide. Driving speed and engine technology are two factors that can affect vehicle emissions. In California, drivers can drive upwards of 70% at speeds above the posted limits. This can cause high uncertainty when modeling vehicle emissions. The first part of this thesis examines both high-speed driving and direct-injection effects on particle concentration and composition while the second part examines the effectiveness of a scrubber technology to remove particulate matter (PM) from large ocean-going vessel emissions. The results show that high-speed driving can affect both total particle count and composition significantly as well as direct-injection technology. Ocean-going vessels equipped with a scrubber are effective at removing gaseous SO2, however, they are not as effective at removing PM or black carbon (BC).