A friend of yours has seen each of the following items i newspaper articles and would like an explanation: \((\mathbf{a}\) acid rain, \((\mathbf{b})\) greenhouse gas, \((\mathbf{c})\) photochemical smog (d) ozone depletion. Give a brief explanation of each term an identify one or two of the chemicals associated with each.

1. Acid rain is caused by the release of sulfur dioxide (SO₂) and nitrogen oxides (NOx) into the atmosphere, where they react to form strong acids that damage the environment and human health. 2. Greenhouse gases, such as carbon dioxide (CO₂), methane (CH₄), and water vapor (H₂O), absorb and emit radiation within the thermal infrared range, causing the greenhouse effect and global warming. 3. Photochemical smog is a toxic mixture of chemicals, including ground-level ozone (O₃), formed when sunlight reacts with nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the atmosphere. 4. Ozone depletion refers to the thinning of the ozone layer, primarily caused by the release of chlorofluorocarbons (CFCs) and other ozone-depleting substances (ODS), which break apart ozone molecules in Earth's stratosphere.