LA

• LA has had a serious problem with photochemical smog for decades because of its high density of vehicles, frequent sunshine and basin topography that traps photo-oxidant gases at low levels. Peroxyacetyl nitrate has been linked to vehicle emissions, and has been deemed particularly hazardous and linked to the LA 'eye-sting'.
• Numerous attempts have been made to improve public transport in the city, but LA is a large, sprawling city and it is much easier to get around with a car. Consequently more recent strategies have included stricter city vehicle emission standards and the Clean Air Action Plan for the port of LA.