Application Exercise 6: Neutralising the Threat of Acid Rain

  1. Mammoth Cave National Park in Kentucky is in close proximity to the coal-fired electric utility plants in the Ohio Valley. Noting this, the National Parks Conservation Association(NPCA) reported that this national park had the poorest visibility of any in the country.a. What is the connection between coal-fired plants and poor visibility?
    Sulfur dioxide are release from the coal-fired plants, creating sulfate particles responsible for 60% to 80% of the poor visibility in eastern parks. 

b. The NPCA reported “the average rainfall in Mammoth Cave National Park is 10 times more acidic than natural.” From this information and that in your text, estimate the pH of rainfall in the park.
Normal rain has a pH range of 5–6, so if the rainfall in this park is 10 times more acidic,the pH range must be 4–5.

2. Here are examples of what an individual might do to reduce acid rain.
For each, explain the 
connection to producing acid rain.

a. Hang your laundry to dry it.


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Hanging laundry to dry requires less energy as compared to using a clothes dryer. An electric dryer required power that are produced by companies through the burning of coal. 

b. Walk, bike, or take public transportation to work.

By walking or taking a bike, we are not burning any energy sources such as coal and gasoline that will contribute to acid rain. Public transportation is better than driving individually as it reduces the amount of gasoline used hence reducing emission. Therefore, contributing less to the acidity of rain.

c. Avoid running dishwashers and washing machines with small loads.
Maximum energy efficiency. Dishwashers and washing machines are powered by companies by burning coal which contribute to the increase acidity of rain.

d. Add additional insulation on hot water heaters and pipes.
Insulating hot water heaters and pipes can reduce heat loss and raise water temperature. Therefore, less coal is needed to be burn to power the above appliances, hence reducing acid rain. 

e. Buy locally grown produce and locally produced food.

 

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Food miles refer to distance a food item had travel from farm to household. Therefore, to conserve energy and reduce global climate change, we should buy more locally grown and produced food. A tremendous amount of fuel are used to transport food long distances. The combustion of fuels will release carbon dioxide, sulfur dioxide, particulate matter and other pollutants into atmosphere, contributing to climate change, acid rain and air pollution. Refrigeration are also required to keep products fresh resulting in more coal used to power it.

3a. Give names and chemical formula for five acid and five bases.
Acid
– Hydrochloric acid: HCI

– Carbonic acid: H2CO3
– Nitric acid: HNO3
– Sulfuric acid: H2SO4
– Sulfurous acid: H2SO3

Bases
– Sodium hydroxide: NaOH

– Potassium hydroxide: KOH
– Calcium hydroxide: Ca(OH)2
– Ammonium hydroxide: NH4OH
– Methyl amine: CH3NH2

3b. Name three observable properties generally associated with acids and bases.
Acids
– The word acid derived from Latin word acere, France word acide & Germany word säure which

means sour. All acids taste sour such as vinegar and lemon juice.
– Acids make litmus (a blue vegetable dye) turn red.
– Acids destroy chemical properties of bases.

Bases
– All bases taste bitter. Mustard and most medicines are bases.
– Bases will restore the original blue colour of litmus after reddened by an acid.
– Bases destroy chemical properties of acids.

4. The concerns of acid rain vary across the globe. Many countries in North America and Europe have websites dealing with acid rain. Either search to locate one (“Canada, acid rain”) or use these links to websites in Canada, the UK, or Europe. What are the issues in Singapore? Does the acid deposition originate outside or inside the Singapore’s borders?

According to Environment and Climate Change Canada (https://www.ec.gc.ca/air/default.asp?lang=En&n=AA1521C2-1), acid deposition is a general term that includes more than simply acid rain. Acid deposition is primarily the result of emissions of sulphur dioxide (SO2) and nitrogen oxides (NOx) that can be transformed into dry or moist secondary pollutants such as sulphuric acid (H2SO4), ammonium nitrate (NH4NO3) and nitric acid (HNO3) as they are transported in the atmosphere over distances of hundreds to thousands of kilometres.

Acidic particles and vapours are deposited in two processes – wet and dry deposition. Wet deposition is acid rain, the process by which acids with a pH normally below 5.6 are removed from the atmosphere in rain, snow, sleet or hail. Dry deposition takes place when particles such as fly ash, sulphates, nitrates, and gases (such as SO2 and NOx), are deposited on, or absorbed onto, surfaces. The gases can then be converted into acids when they contact water.

A research was conducted by Balasubramanian, R.; Victor, T.; Begum, R., Tittle: Impact of biomass burning on rainwater acidity and composition in Singapore, in 1999.
 http://scholarbank.nus.edu.sg/handle/10635/92044

The research look into the impact of the Indonesian forest fires that took place from August through October 1997. Large amounts of gaseous and particulate pollutants were released into the atmosphere. The particulate emissions produced a plume that was easily visible by satellite and significantly affected regional air quality in Southeast Asia. The prolonged haze episode provided an unprecedented opportunity to examine the effects of biomass burning on regional atmospheric chemistry. The researchers undertook a comprehensive field study to assess the influence of biomass burning impacted air masses on precipitation chemistry in Singapore. Major inorganic and organic ions were determined in 104 rain samples collected using an automated wet-only sampler from July through December 1997. Mean pH values ranged from 3.79 to 6.20 with a volume-weighted mean of 4.35. There was a substantially large number of rain events with elevated concentrations of these ions during the biomass burning period. The relatively high concentrations of SO4 2-, NO3 -, and NH4 + observed during the burning period are attributed to a long residence time of air masses, leading to progressive gas to particle conversion of biomass burning emission components. The decrease in pH of precipitation in response to the increased concentrations of acids is only marginal, which is ascribed to neutralization of acidity by NH3 and CaCO3.