A woman protects herself from the sun

De Middel

© Cristina de Middel (in collaboration with Bruno Morais) / Magnum Photos


An umbrella full of holes: are acid raindrops falling on our heads? Of course, we’re not talking about acids that could quickly eat hoes in objects like we might see in horror or science fiction films, but nitrogen oxides (NOx) and sulphur oxides (SOx) that are released into the atmosphere where they combine with water vapour to form acids (nitric acid and sulphuric acid) that then fall to the ground in the form of acid rain. Although these oxides can have a natural origin as a result of volcanic activity, they are primarily the result of fuel combustion in vehicles and industrial activities.
Acid rain can have a variety of effects depending on the surface with which it comes into contact: while normal rain has a pH of 5.6, acid rain has a pH of between 4.2 and 4.4. If acid rain accumulates in lakes, streams or swamps, it raises the water’s acidity level, increasing the absorption of aluminium and other heavy metals, and making the water more toxic for all of the living beings that depend on it. Woods and forests also suffer similar dangerous effects: when acids deposit in the soil, they allow aluminium and calcium to be released, making it difficult for the plants’ roots to absorb water.
The phenomenon affects us as well since acid rain can cause damage to our buildings, cars and monuments.  It also has toxic effects on human health, irritating the eyes and causing respiratory issues when it mixes with fog.
This problem can be moderated in many ways: by replacing fossil fuels with renewable energy sources, reducing our use of cars in favour of public transport or bicycle use, and increasing the use of catalytic converters and instruments to absorb oxides. While options exist, they're not sufficient to change the situation: what is still missing is a strong will for change.

Andrea Pozzobon