Scorching days may bring heavy smog, which can damage the lungs. Everyone is affected by smog, but children and the elderly are the most vulnerable. The following tips help reduce smog and protect health. (a) Heed air quality warnings on news broadcasts. (b) Use public transportation, bicycle, walk or carpool. (c) Keep your car tuned and your tires properly inflated. (d) Make sure your car's air conditioner is not leaking coolant. (e) Do not top off the gas tank; this releases smog-forming pollutants into the air. (f) Try to avoid filling the tank on heavy smog days, or fill up during the cooler morning and evening hours. (g) Avoid aggressive driving. Jackrabbit accelerations (flooring the gas pedal), excessive speed and hauling heavy loads increase emissions and decrease fuel efficiency.In 1999, the European Commission submitted two proposals for combating ozone pollution. The first of them set ceilings on harmful emissions of several chemical substances which contributed to the formation of ozone, while the second sought to introduce binding threshold values for ground level concentrations of ozone.