Acid rain

What is acid rain

Rain, fog and snow are normal atmospheric phenomena and, as long as they do not become cataclysms, they make our life nicer or unpleasant whereas globally they regulate the water balance of our planet. Clean rain has a salutary influence on flora, soil irrigation, it purifies the air with dust - such rain, due to the content of carbonic acid witch is characterized by a slightly acidic reaction (ph 5.6). The existence of carbonic acid in rain is the result of the reaction between carbon dioxide, which is emitted, among others, by us in the process of breathing, and water molecules accumulated in the atmosphere; it is weak and impermanent acid and its trace the amount in atmospheric fall is the consequence of natural life processes. The ph of acid rain is much lower, it is polluted not only by carbonic acid but also other, much more dangerous acids, such as sulfuric, nitric and hydrochloric acid.

Contrary to carbonic acid, they are highly caustic substances: sulfuric acid burns human skin and all organic compounds (carbon compounds), nitric acid causes serious burns and hydrochloric acid, that is found in our digestive juices in low concentration, dissolves metals (after mixing with nitric acid it dissolves even gold and platinum).

In acid fall these acids occur in low concentrations and it would be difficult to observe their immediate effects, unfortunately, due to the constant emission of nitrogen oxide, sulfur dioxide, hydrogen sulphid or hydrogen chloride - a substance which quickly reacts with water and other compounds which are found there - acid rain, owing to gradual, consistent influence becomes an atmospheric phenomenon that wreaks havoc on the surface of the Earth.

How is acid rain formed

Acid rain is the effect of the polluted air with chemical substances which, as the result of reactions which take place in the air, create acids which, accordingly, combine with water vapour and pollute the air.

Some of the chemical substances (about 50% of sulfur and nitrogen compounds) get into the atmosphere as the result of natural processes such as volcanic eruptions and the processes of the decay of organic matter; in and of themselves these natural processes are not such a huge problem.

However, as the result of industrialization which develops very fats, human activity has become the main generator of compounds acidifying rainfall. The majority of sulfur and nitrogen compounds emitted to the atmosphere is the effect of using, in various types of processes, fossil fuels such as coal, petroleum and natural gas. Additional factor which acidifies is organic and inorganic compounds contained in exhaust fumes.

Acid rain in the form of dust, gases and rain is the effect of removing molecules which are in the air, on the surface of the Earth. It is called aggravation in a dry form (dusts and gases) or wet (rain, fog, snow etc.). Dry fall is mainly a local threat. Acid dusts usually fall near the sources of pollution. On the other hand, wet fall is more mobile - acid rain may fall even 1000km from the source which emitted the pollution. Moreover, the harmfulness of wet fall is caused by the fact that acids absorb water very well and cause its condensation and accordingly they speed up the process of cloud creation. Acidified clouds are inasmuch as dangerous that pollutions which accumulate in them undergo constant chemical reactions due to which new, harmful substances arise.

Acid rain effects

Acid rain influences nearly everything: environment, infrastructure, us.

Let us start from the environment. Acids contained in rain get to soil, settle on plants and get in them damaging seriously their structure - they leach calcium and magnet from them which consequently leads to the death of leaves and needles. Plants become unable to function properly, their water balance and photosynthesis are disturbed and they gradually die. Acidified soil poisons roots which hinders supplying with nutritional substances. The plant becomes weaker, it is more subject to diseases, it gives up in the fight for survival. It dies.

All over Europe forests die because of acid rain at an alarmingly fast rate - in 1985 in more than a half of forests in RFN there were damages, to a bit smaller degree forests were also damaged in Netherlands, one third of forest area in Switzerland, Czech Republic and Slovakia also dies due to the influence of acid rain, what is more, it is estimated that from 200 thousand to 300 thousand hectares of forests are completely dead in our southern neighbors.

Acid rain has a destructive influence on whole ecosystems (an ecosystem is a distinguished unit within the environment which consists of inanimate matter and living organisms and they all function within one cohesive entirety and closely depend on each other).

One of the most important problems is the pollution of water ecosystems; scientists raise the alarm that soon only in North America about 50 thousand lakes will die biologically. Waters polluted with acid become barren, they lack food for organisms which live there. Not only do lakes die but also all organism which depend on the given water body - birds nesting nearby stop reproducing, animals in forest degraded by acid are subject to the loss of food.

Another issue - the areas of arable land become smaller, as the result of acidifying, the land becomes unfit for farming, they need to be fertilized, usually with soil lime.

Acid rain has also considerable impact on our health: first of all on respiratory and vascular system - and accordingly on the whole organism. A particularly drastic example is acid fog, so-called London smog (the mixture of fog, acid and soot) due to which, in 1952, 4000 people died in London. Acid pollution causes problems with respiratory system (cough, asthma, bronchitis), headaches, eye aches, sore throat, problems with breathing - in case of ill people, the symptoms may worsen so much that they may lead to death. Acids are also the reason for cancer - they leach heavy metals from the environment which pollute, among others, the water we drink. These metals, accumulated in an organism, are the cause of cancer, Alzheimer's disease and diseases of excretory system (kidneys). This pollution concerns not only people but all organisms whose survival depends on water and air.

Acid rain also damages infrastructure: buildings, monuments - so they damage our culture heritage. Limestone and marble are particularly subject to their destructive influence but also constructions made of metal corrode under the influence of fall. Acid rain wreaks havoc in valuable monuments, for instance: Westminster Abbey in London was damaged so much that since the 90s the renovation has cost 10 million pounds.

Acid rain law regulations

The first steps were undertaken in the 70s but they did not concern the prevention of acid rain. Only research programmes which focused on the causes and consequences of acid rain were established.

In the 80s the international cooperation began, its aim was to limit the emission of pollution acidifying fall.

In 1979 the Geneva Convention on "long-range transboundary air pollution" was signed. The aim of this agreement was to strive for an environmental protection by limiting air pollution (protection, limiting emissions and decreasing the emission of harmful substances).

Other protocols are:

• The Geneva protocol from 1984 where it was decided that the monitoring programme would be created and financed and the evaluation of pollution transfer would be carried out.
• The Helsinki protocol from 1985.
• The Sofia protocol from 1988 - the act relative to the limitation of nitrogen oxides.
• The Goteborg protocol from 1999 - the aim of the protocol is to prevent acidifying by the limitation of the sulfur dioxide emissions, nitrogen oxides, gaseous organic compounds and ammonia.

The influence of acid rain on tropical rainforests

Tropical rainforests are the biggest forest area in the world. They constitute 6% of the whole area of the Earth and they have great significance in water and heat balance on our planet. What is more, these forests are home for the half of the species of plants and animals we are familiar with. They are a treasure trove of nature which acid rain threatens.

The main danger to rainforests is human's wasteful economy. The forest are cut own and burnt. The processes are mainly connected with industrialization and accordingly they carry acid rain threat which is local (burning - carbon dioxide, industry - sulfur dioxide and nitrogen oxides). Furthermore, omnipresent and very mobile cloud and air pollution also do not omit the tropics. Even rain acidified to a very small degree whose whole total yearly fall is from 1000 to 2000 mm, destroys ever-green tress whose vegetation period lasts a whole year.