The acidity or alkalinity of precipitation is quantified by its pH, a scale ranging from 0 to 14. A value of 7 is neutral; values below 7 indicate acidity, while values above 7 indicate alkalinity. Naturally occurring atmospheric carbon dioxide dissolves in atmospheric moisture, forming carbonic acid, which contributes to the slight acidity of uncontaminated precipitation. This process results in a typical pH level for clean precipitation.
Understanding the acidity of precipitation is crucial for assessing its impact on ecosystems, infrastructure, and human health. Lower pH levels can accelerate the weathering of stone and metal structures, negatively affect aquatic life in lakes and streams, and impact soil chemistry. Monitoring and analyzing precipitation pH provides valuable data for environmental protection and pollution control efforts. Historically, significant alterations in precipitation chemistry have been linked to industrial emissions and other anthropogenic activities, highlighting the importance of continued monitoring and mitigation strategies.
