pollutants imp.

• What toxic gas is produced from incomplete combustion?

  Carbon monoxide
• What environmental issue does sulfur dioxide cause?

  Acid rain
• Where does sulfur dioxide come from?

  Sulfur impurities in fossil fuels
• What forms when sulfur dioxide mixes with clouds?

  Dilute sulfuric acid
• What happens when dilute sulfuric acid falls as rain?

  It causes acid rain
• What are the effects of acid rain on lakes?

  Lakes become acidic, harming plants and animals
• How does acid rain affect trees?

  It causes trees to die
• What materials are damaged by acid rain?

  Limestone buildings and some metals
• What are nitrogen oxides?

  Pollutants created from nitrogen and oxygen
• What harmful effects do nitrogen oxides have?

  They cause photochemical smog and acid rain
• What is photochemical smog?

  A type of air pollution causing breathing difficulties
• What can hydrogen be used as?

  A renewable fuel
• What is the main waste product of hydrogen fuel?

  Water
• How is hydrogen obtained?

  From water, a renewable resource
• What is a disadvantage of using hydrogen as fuel?

  It requires a special expensive engine
• What is a challenge in storing hydrogen gas?

  Hydrogen is difficult to store