Acid rain Acid rain Acid rain is a rain or any other form of precipitation that is unusually acidic, meaning that it has elevated levels of hydrogen ions (low pH). It can have harmful effects on plants, aquatic animals and infrastructure. Acid rain is caused by emissions of sulphur dioxide and nitrogen oxide, which react with the water molecules in the atmosphere to produce acids. Some governments have made efforts since the 1970s to reduce the release of sulphur dioxide and nitrogen oxide into the atmosphere with positive results. Nitrogen oxides can also be produced naturally by lightning strikes, and sulphur dioxide
Nitrogen dioxide poisoning likely to develop within the alveolar ducts, tiny ducts that connect the respiratory bronchioles to alveolar sacs, each of which contains a collection of alveoli (small mucus-lined pouches made of flattened epithelial cells). The overall reaction may cause an obstructive lung disease. Meanwhile, proliferative bronchiolitis is a secondary effect of nitrogen dioxide poisoning. The EPA have some regulations and guidelines for monitoring nitrogen dioxide levels. Historically, some states in the U.S including Chicago, Northeast corridor and L.A have had high levels of nitrogen dioxide. In 2006, the WHO estimated that over 2 million deaths result annually from air pollution in