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 Nitrogen dioxide poisoning Nitrogen dioxide poisoning is the illness resulting from the toxic effect of nitrogen dioxide (). It usually occurs after the inhalation of the gas beyond the threshold limit value. Nitrogen dioxide is reddish-brown with very harsh smell at high concentrations. It is colorless and odorless at lower concentration but still harmful. Nitrogen dioxide poisoning depends on the duration, frequency, and intensity of exposure. Nitrogen dioxide is an irritant of the mucous membrane linked with another air pollutant that causes pulmonary diseases such as OLD, asthma, chronic obstructive pulmonary disease and sometimes acute exacerbation of COPD and in