Acid rain, once a major issue, has diminished due to strict regulations and cleaner technologies.

NORFOLK, Va. — Acid rain is a serious environmental problem caused by air pollution. It forms when sulfur dioxide and nitrogen oxides are released into the atmosphere, mainly from burning fossil fuels like coal, oil, and gas in power plants, factories, and vehicles.

These gases mix with water vapor and turn into sulfuric and nitric acid, which fall to Earth during rain, snow or fog. Normal rain has a pH level of around 5.6, which is slightly acidic, compared to acid rain, which has a pH level between 4.2 and 4.4.

When acid rain reaches the ground, it can have harmful effects on the environment. It lowers the pH of soil and water, making it difficult for plants to grow and often deadly for fish and other aquatic life. Acid rain also damages forests, especially at higher altitudes, by leaching nutrients from the soil and harming tree leaves and bark. In addition, it corrodes buildings and monuments, particularly those made of limestone or marble.

Acid rain was a major environmental issue in North America and Europe during the 1970s and 1980s. Lakes were dying, forests were suffering, and historic buildings were eroding. However, significant progress has been made. The introduction of strong environmental regulations, such as the U.S. Clean Air Act Amendments of 1990, helped reduce the emissions that cause acid rain. Technologies like scrubbers in smokestacks and cleaner vehicle engines also played a major role.