Learning objectives: To be able to describe the causes, consequences and responses to a transboundary pollution event Key terminology Transboundary International Point source Diffuse source

Acid rain – What is it? Any form of precipitation with high levels of nitric and sulfuric acids Two forms, wet deposition and dry deposition. Wet deposition - pollutants mix with rain water and fall to the ground as acidic precipitation. Dry deposition - pollutants and particulates fall to the ground without mixing with rain water. Some acid rain has had pH levels as low as 2

Why is acid rain transboundary? Describe the distribution of the ‘acid rain problem’

Main contributors to acid rain Sulphur dioxide and nitrous oxides = two main chemicals that react with water to make acid rain. The chemicals are commonly released from power stations, factories and transport. 

Sulfur dioxide and nitrogen oxides react with water, oxygen and other substances to form mild solutions of sulfuric and nitric acid. Winds spread acidic solutions across the atmosphere and over hundreds of miles When acid reaches Earth it flows across water surface in runoff and enters water systems and sinks into the soil.

Impacts of acid rain Damage to buildings Metals (iron, aluminum, etc.) dissolved by acid rain can be washed into water courses Vegetation can be damaged and growth reduced Lakes and rivers can become acidic harming the ecosystem and aquatic life Soil acidity increases

Impacts of acid rain http://www.conserve-energy-future.com/causes-and-effects-of-acid- rain.php Make summary notes on: Aquatic environment Forests Soil Vegetation and plant cover Buildings Health

Acid rain in China What are the causes and effects of acid rain in China? http://news.bbc.co.uk/2/hi/asia-pacific/5290236.stm

Responses to acid rain http://www.scientificamerican.com/article/soils-start-comeback- after-acid-rain-damage/ http://news.bbc.co.uk/2/hi/uk_news/4436910.stm What were the responses and how successful were they?