Have we forgotten acid rain?

Emissions from coal power stations contribute to acid rain.

IN the late 1960s at a nautical college, the cadet officers’ knowledge needed broadening beyond their chosen subjects. One of my remits was to develop a course which I entitled EEC. Most cadets thought I would be talking about the then fashionable subject of the European Economic Community. To their surprise my course was on Environment, Ecology, and Conservation.

In the 1960s, climate change was almost unheard of. Instead ‘acid rain’ was on everyone’s tongues, nowhere more than in Scandinavian countries where the finger for its cause was demonstratively pointed towards its main source, the British Isles. Today, this subject is often overlooked.

What is acid rain?

First detected in 1853 and coined ‘acid rain’ in 1872, it is defined as “precipitation in the form of rain, hail, sleet, snow, dew or fog that transports sulphur and nitrogen compounds from the high atmosphere to ground level”. Industrial operations, which burn fossil fuels to generate electricity, together with oil and gas refineries, domestic chimneys, volcanic eruptions and combustion exhausts from vehicles all release sulphur, nitrogen and carbon gases into the atmosphere. These, in turn, combine with water droplets to create sulphur dioxide, nitrogen oxides, and carbon dioxide which, through the process of precipitation, are transferred to our soils, buildings, lakes and oceans.

Sulphur dioxide is an acid gas as it is converted in the atmosphere to ammonium sulphate but reacting with water it forms hydrogen sulphite or hydrogen sulphate. Nitrogen oxides can also be produced by lightning, thus tropical downpours in the daily deluges of acidic rain. With so many active volcanoes in parts of Indonesia, daily emissions of sulphurous gases and steam lead to convectional acidic rainfall.

In short, dilute sulphuric or nitric acids are falling on our heads wherever we are on the globe. In chemical terms, acidic rain has a pH of less than 5.6.

Remember your Chemistry lessons at school? Just a quick refresher. Neutral point is pH (potential hydrogen ions) 7, greater than pH7 is alkaline, and less than pH7 is acidic. When, over the years, I have been asked numerous times by my inquisitive grandchildren, “Why are you bald, Grandpa?” or, “Why did you lose your hair?” I have simply replied, “Because of acid rain, for I have never worn a hat!”

Other forms

In the absence of any form of precipitation, pollutants can just fall out of the air, sticking to the leaves of plants, buildings, and ground surfaces to be triggered into acidic reactions in the next rain shower and thus leading to the deterioration of such surfaces.

Different plants adapt in different ways to their specific tolerances of sulphur dioxide. The UK common lichens (Lecanora conizaeoides) on trees and buildings can tolerate high doses of this compound but other species of the bearded genus (Usnea), trailing from tree branches, tend to die away.

In Manchester, for example, only two species of lichen are obvious on tombstones in the city centre whereas, only 15km away, in the southwestern suburbs, as many as 150 lichen species are evident in a graveyard. Lichens act as natural pollution monitors as their growth rates are stunted or killed by acid rain and particularly by sulphur dioxide fall out.

Effects of acid rain

Few studies, if any, have been conducted of the effect of acid rain on animals, but for people who suffer from attacks of asthma and bronchitis, there is a direct correlation with higher than average levels of sulphur dioxide in the air. In the notorious ‘pea-souper’ London smog from Dec 5-9, 1952, some 4,000 deaths in that short time were attributed to high sulphur dioxide levels in fog, when visibility was reduced to between five and 10 metres.

Despite the UK’s Clean Air Act of 1956, which permitted British cities to establish smokeless zones, sulphur dioxide is still a major pollutant contributing to acid rain. Since this Parliamentary Act was passed, factory chimneys have been built two to three times higher but the pollutants, while reduced locally, are spread out further downwind into previously uncontaminated countryside and other urban areas.

International problem

Relatively recently, Indonesian cities have honestly recorded their average acidic levels of rainfall inputs. Manado rain has a pH of 4.2, Pontianak – pH 4.3, Bogor – pH 4.4, and Jakarta – pH of 4.5. These figures do not represent the acidic pH levels of localities closest to the active volcanoes.

Sweden’s ecosystem has been turned upside down by acidic rainfall damage to its soils and its more than 18,000 natural lakes, where, as with its neighbour Norway, freshwater species of fish have died out. Forest trees in both countries, with the prevalence of Norway spruce (Picea abies) and Silver fir (Abies alba), have shown a loss of pine needles and the death of their upper twigs. Sweden reckons that it receives 10 per cent of its sulphur dioxide from oil refineries emissions in northeast of England. From there the atmospheric pollutants, swept on prevailing winds, land as acidic rainfall on Scandinavian countries. To combat the acidification of lakes, aeroplanes ‘spray’ the lakes with lime to help return the waters to a more neutral pH in the hope that fish may thrive again.

Visits to historic buildings such as the Parthenon in Greece or the Taj Mahal in India reveal sections of crumbling limestone and sandstone pillars with their once intricately carved effigies. Even modern buildings constantly display peeling paint and corrosion in their steel and concrete structures. Many buildings, constructed in the last three centuries since the start of the Industrial Revolution in 1752, if built of limestone, display acid rain pock marks.

Punishing the environment

It is beyond my grasp as to why we continue to pollute our own atmosphere. We live in a world of so-called ‘developed’ or ‘developing’ nations, where respective governments either don’t realise the consequences of, or more likely turn a blind eye to, environmentally damaging industrial expansion. Making industries cleaner costs money. ‘Clean’ factories cannot produce the goods as cheaply as ‘dirty’ factories. Developed and developing countries receive massive profits from the production, refinement and supply of fossil fuels, mainly through taxes.

Transboundary air pollution was discussed and signed by very many countries at the 1995 Helsinki Protocol on the reduction of sulphur emissions. Now, 23 years later, how many nations have offered subsidies or financial help to industries for new technological ways of reducing their atmospheric polluting agents? The ‘muck’ is still there in the air that we breathe and in the acidic rain that falls on our heads as well as on animals, insects, fish, and on our soils and buildings.

Are we prepared, through direct or indirect taxation, to meet the governmental costs of reducing acidic gasses emissions to rid our planet from these scourges? Surely the industrial and commercial giants of our world must bear the brunt of such costs, even if it means cutting annual profits and without passing on their environmental responsibilities to the consumer.

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