March 2010 went down memory lane as the month rumours of Acid rain were spread all over Nigeria. Many were misguided about Acid rain. Some said that a particular rain will fall in that month which falls once in 750 years, and it is carcinogenic. Is it really true that a particular Acid rain falls on earth once in 750 years? Science Writer, STANLEY CHIBUIHEM AMALAHA takes a look at this Acid rain brouhaha
Seven years ago (March 2010) to be precise, Nigerians were traumatised over ‘ACID RAIN’. Sadly they were misguided about the phenomenon because of indequate scientific knowledge and sensitization
“Hey, Mary! Please don’t enter rain when it is falling because there is an acid rain that will fall this month, it will cause skin cancer when it touches you. Please Mary, make sure you stay indoors throughout this period: These were the words of Miss Lynda Anthony, who resides in Apapa, Lagos, to her beloved sister, Miss Mary Anthony. This advice was for all ages not for Mary alone. It was rumoured that a particular rain that will fall in the month of March (2010) will be acidic in nature and highly carcinogenic.
Miss Judith Emeh, who was at the University of Benin, presently serving at Ekiti State Nigeria, by then, was not left out, as she received series of text messages in her mobile phone not to allow any rain in that month to touch her skin because it is ‘acid’ Some of the text messages were quite simple and short.
“Judith please don’t enter rain within this period of March.” Another text from her brother said, adding: “Judith, there is a rain which falls once in 750 years, which will fall within this period, please stay indoors so that it will not touch you because it is harmful to the body!” Her brother Mr. Obiora Emeh, who resides in Kaduna Nigeria, was so caring and was sending the text over and over again to her sister, Judith. He also sent the messages not only to his sister, but to all his friends and relatives.
Mary Anthony said that she was advised to stay off the rain. That even if she is in the market place or in the church, or anywhere at all, she should not allow the rain to touch her. She also received series of text messages. Indeed, the rumour was spreading like wild fire during harmattan says Miss Lynda Anthony. People were backing their claims from meteorological centre of unknown destination. However, some said the centre was from Abuja while others claimed it was from USA. There were different views from different people about acid rain.
The question now is: was it true that March 2010 really experienced a particular acid rain that was carcinogenic to the human body? Let’s look at the evidence.
ACID RAIN FORMATION
There are two major unhealthy compounds produced by burning of fossil fuels. These are oxides of sulphur and nitrogen. When these oxides combine with water in the atmosphere, they form acids. These acids fall on the ground as acid rain the truth in the matter is that most of the early rains that fall at the beginning of the year, contain some percentages of acidity. Natural rain is slightly acidic because it reacts with CO2 in the air to form carbonic acid. H2O + CO2 H2CO3
Natural rain water has a PH. of about 5.6 which is slightly acidic but not harmful. The PH scale is a scale ranging from 0 to 14 used to classify acidity and basicity of solutions. PH value of 0,1,2 and 3, are more acidic than those with PH values of 4,5, and 6. Acidic values range from 0 to 6. The lower the number, the higher the acidity.
A PH value of 7 is neutral, while PH values from 8 to 14 signify basicity. However, the acidity of natural rain water differs slightly in different parts of the world e.g. in Central Europe, the PH is about 4.1 while in Ireland and Portugal, it is about 4.9. Acid rain which is becoming a global phenomenon has a PH below 5.0. It is primarily caused by oxides of sulphur and nitrogen namely: Sox and NOx respectively which are acidic, corrosive and poisonous.
People living in highly industrialized areas where cement companies and other related companies are located, are likely to experience rain with higher percentage of acidity than those living away from these companies if other factors like carbon emissions from cars are equal. When sulphur containing coal is burnt, it gives of SO2. Similarly, when combustion of fuels occur at high temperatures, oxides of Nitrogen (e.g. NO2) are produced, when rain falls, these gases dissolve in rain water and produce acids known as “acid rain” as shown in the equation below.
NO + O3 —> NO2+O2
NO2 + 2O2 —> NO3+O3
NO2 + NO3 —> N2O5
N2O5 + H2O —> 2HNO3
Nitrogen oxides from automobile exhaust combine with moisture in air to make dilute solutions of nitric acid as shown in the earlier equations. On the other hand, when coal burns from cement producing companies, the sulphur it contains, combines with oxygen in the atmosphere and acid rain is formed as shown below:
S+ O2(g) SO2(g)
From burning coal containing sulphur
2SO2(g) + O2 (g) 2SO3(g)
Converting to sulphur trioxide
SO3(g) + H2O (I) H2SO4(aq)
Dissolving sulphur trioxide to form sulphuric acid.
EARLY YEAR RAIN FALL
Generally most rain that fall early in the year have some percentages of acidity which are not harmful.
However, over exposure to rain tarnishes and corrodes our statues, and monuments.
A typical example is the corrosion of the famous statue of Liberty in the city of New York which was refurbished few years ago. Science Telegraph recalled how he collected a sample of the rain by then and tested it in the laboratory and found that the rain was a normal rain.
This led him to different television stations include: NTA Victoria Island Lagos; Silverbird Television Ajah Lagos; Television Continental Ikeja, Lagos; and Super Screen Television Jibowu Lagos to enlighten Nigerians on Acid rain. The truth in the matter is that there is no particular acid rain that falls once in 750 years.
The ‘acid rain’ of March 2010 was indeed a charade.