So many thoughts are swimming around my head, demanding further explanations and popping up more questions. Yup, I finished the book ('Rainwater And You' - if you didn't see the previous post, please read that one first), and I'm left slightly numb with all the new information. There is so much I didn't give enough thought to, and heaps more that I want to find more about. The next step to take, though, is surely not to run about wildly flapping my hands with a 'Help' sign but to organize what I've learned, adding further knowledge, evidence and ideas. I will be posting several more posts for the weeks to come. I'm sorry that my posts will be up with varying lengths of intervals between; I try to find at least a few satisfactory answers before I post, and the time this takes is unpredictable. Still, the next post will be up in less than a week, so keep up with the updates!
Firstly, we have to talk about textbooks. While this book only deals with Korean ones, books I studied from in my middle school years and IGCSE curriculum all had similar information. The overall picture is this: human activity releases harmful gases into the atmosphere, causing air pollution. Sulfur dioxide from burning fossil fuels and oxides of nitrogen from car engines form acid rain in damp air. * Acid rain causes great damage to forests, crops, lakes, stonework and metal in buildings. The books I used to study from didn't have detailed chemical reactions, but my classmates and I got the general idea. Acid rain is dangerous, and is partly the reason why we see horrifying pictures of dead fish by the shore - lifeless eyes, dirty scaled skin and blackened teeth. Such images hunt us from the very first time we see them.
This book claims that rainwater cannot have caused such damage. This applies to most areas around the world, but definitely to the Korean peninsula. As mentioned in the previous post, the yellow dust that swept to the land for the past centuries is mixed with the soil. According to the book, more than 1 million tonnes of yellow dust land every year. Basically, there is enough on Korea to neutralize any acid rain that falls. Furthermore, it is not just the yellow dust that has this effect - even if "a bit of dust" gets added to rain, it gets neutralized.
Professor Han explains an experiment he conducted on the roof of a university building. The pH of rain collected on a clean dish was 5.6 - a weak acid. The rain that flowed down the dusty roof, however, was alkaline - 7 ~ 8.5 in pH. He also observed that the pH rose further as time passed by.
When asked about the destruction of lake ecosystems in Scandinavia**, Professor Han says a big part of the reason is the territorial characteristics. There are only lots of rock, thus, there is little to neutralize acid rain. He adds that he heard bits of calcium carbonate is sometimes thrown over the lake for neutralization. He goes on to say that such events have usually taken place long ago - as late as the 1950s. This was a time when air pollution was much more severe than the present, to such an extent that a walk through smog could result in death. The professor states that stories of such events are "more history than science".
The interviewer in the book asks the professor about a Korean newspaper article from 1989, published by the Forestry Research Institute. Research in the Hongneung forest area showed the lowest pH of 3.7, highest of 7.6 and average of 4.7. Professor Han says it is hard to understand pH levels as low as 3.7 could be found in forests. If there was exceptional air pollution in the area, perhaps, it could be a reason why. He states, however, that pH of 7.6 is "strange". Rain that goes through clean water has pH of about 5.6. Yellow dust season could be a way to explain this unusual alkaline rain, except it would contradict the pH 3.7; rain cannot have such a low pH when there is yellow dust in the atmosphere. The professor says rain of high pH may have been collected from the ground, which would suggest a situation similar to that of his experiment. He concludes that without knowing the specific method of measurement, he cannot be completely sure.
The answer he gave for the next question, though, was a little unsatisfactory. The interviewer asks about the possible harmful effects of directly getting in contact with acid rain. *** The professor replies that he is not a medical expert, but doesn't think it would be bad for our health. He compares the situation to taking a bath in a hot spring of high sulfur levels. The water is much more acidic than most rain, but nobody considers that the bath could be dangerous. I think this is a poor answer in a few ways. Just as he explained, the rainwater loses its acidity when it flows down a surface or lands on the ground. But the interviewer specifically asked about rain that fell directly on us, not after contact with another object. Surely the example of the bath is not a very suitable comparison. Moreover, there is a notable difference in his attitude in addressing this question. Only a few pages earlier in the same chapter does he pronounce the absurdity of getting harmed in any way through rain. He clearly says that there is no reason to be afraid of acid rain falling on us. What caused this sudden change in the tone? These are only minor details, but they nevertheless make me pause in my tracks.
In case some of you are wondering, I couldn't find a satisfactory answer on the Internet about the type of acidity which I talked about in the previous post. When school starts after the spring break ends (soon) I will ask my earth science professor and chemistry professor about it! Keep up with the updates!
* For anyone who's interested: the beautiful chemistry of it!
Nitrogen Oxides:
N2(g) + O2(g) -> 2NO *This takes place with lightning
NO(g) + 0.5O2(g) -> NO2(g)
3NO2(g) + H2O(l) -> 2HNO3(aq) + NO(g)
Then nitric acid dissociates into H+ ions and NO3- ions.
Since this takes place in water, it lowers its pH.
Sulfur Dioxide
S(s) + O2(g) -> SO2(g)
SO2(g) + O -> SO3(g)
H2O(l) + SO3(g) -> H2SO4(aq)
Then sulfuric acid dissociates into H+ ions and (SO4)2- or HSO4- ions.
This also takes place in water, thus lowering its pH.
** See the following websites for more information:
http://www.environment.no/Topics/Air-pollution/Acid-rain/
http://sustainabilityandthecommons.wordpress.com/2010/11/08/scandinavian-moan-acid-rain/
*** The majority of people in Korea fear rain falling on them; this may be different in other parts of the world.
 |
| Image from the NY Department of Environmental Conservation http://www.dec.ny.gov/chemical/8418.html We have seen such images in many textbooks! |
This book claims that rainwater cannot have caused such damage. This applies to most areas around the world, but definitely to the Korean peninsula. As mentioned in the previous post, the yellow dust that swept to the land for the past centuries is mixed with the soil. According to the book, more than 1 million tonnes of yellow dust land every year. Basically, there is enough on Korea to neutralize any acid rain that falls. Furthermore, it is not just the yellow dust that has this effect - even if "a bit of dust" gets added to rain, it gets neutralized.
Professor Han explains an experiment he conducted on the roof of a university building. The pH of rain collected on a clean dish was 5.6 - a weak acid. The rain that flowed down the dusty roof, however, was alkaline - 7 ~ 8.5 in pH. He also observed that the pH rose further as time passed by.
When asked about the destruction of lake ecosystems in Scandinavia**, Professor Han says a big part of the reason is the territorial characteristics. There are only lots of rock, thus, there is little to neutralize acid rain. He adds that he heard bits of calcium carbonate is sometimes thrown over the lake for neutralization. He goes on to say that such events have usually taken place long ago - as late as the 1950s. This was a time when air pollution was much more severe than the present, to such an extent that a walk through smog could result in death. The professor states that stories of such events are "more history than science".
The interviewer in the book asks the professor about a Korean newspaper article from 1989, published by the Forestry Research Institute. Research in the Hongneung forest area showed the lowest pH of 3.7, highest of 7.6 and average of 4.7. Professor Han says it is hard to understand pH levels as low as 3.7 could be found in forests. If there was exceptional air pollution in the area, perhaps, it could be a reason why. He states, however, that pH of 7.6 is "strange". Rain that goes through clean water has pH of about 5.6. Yellow dust season could be a way to explain this unusual alkaline rain, except it would contradict the pH 3.7; rain cannot have such a low pH when there is yellow dust in the atmosphere. The professor says rain of high pH may have been collected from the ground, which would suggest a situation similar to that of his experiment. He concludes that without knowing the specific method of measurement, he cannot be completely sure.
 |
| Even light snowfall means umbrellas and hoods |
In case some of you are wondering, I couldn't find a satisfactory answer on the Internet about the type of acidity which I talked about in the previous post. When school starts after the spring break ends (soon) I will ask my earth science professor and chemistry professor about it! Keep up with the updates!
* For anyone who's interested: the beautiful chemistry of it!
Nitrogen Oxides:
N2(g) + O2(g) -> 2NO *This takes place with lightning
NO(g) + 0.5O2(g) -> NO2(g)
3NO2(g) + H2O(l) -> 2HNO3(aq) + NO(g)
Then nitric acid dissociates into H+ ions and NO3- ions.
Since this takes place in water, it lowers its pH.
Sulfur Dioxide
S(s) + O2(g) -> SO2(g)
SO2(g) + O -> SO3(g)
H2O(l) + SO3(g) -> H2SO4(aq)
Then sulfuric acid dissociates into H+ ions and (SO4)2- or HSO4- ions.
This also takes place in water, thus lowering its pH.
** See the following websites for more information:
http://www.environment.no/Topics/Air-pollution/Acid-rain/
http://sustainabilityandthecommons.wordpress.com/2010/11/08/scandinavian-moan-acid-rain/
*** The majority of people in Korea fear rain falling on them; this may be different in other parts of the world.
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