What Causes Acid Rain and How Can We Prevent It?

A healthy environment is balanced. Each component – carbon, oxygen, water and wildlife, e.g. – must be present within certain boundaries. Too much or too little can upset the equilibrium and cause all kinds of consequences. One such outcome is acid rain. When rainfall, or any other form of precipitation, contains acid, it penetrates waterways and soil with alkaline elements. In so doing, the aluminum levels rise and aquatic life is poisoned. The creatures that feed on them are also affected.

What Causes Acid Rain?

what causes acid rain

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Power Plants

A major factor in acid rain is the burning of fossil fuels to produce electricity. Coal-burning power plants discharge sulfur into the air. Once present in the atmosphere, the sulfur bonds with oxygen to form sulfur dioxide (SO2). Existing in airborne particulates, SO2 contributes to asthma complications and other respiratory difficulties. As a gas, it is known to stunt the growth of plants when highly concentrated. Furthermore, in tandem with other unwelcome compounds, SO2 decreases visibility by producing haze, a problem in many U.S. parks and historic sites.

When captured and carried by rainfall, SO2 reduces the pH (the count that measures the alkaline levels) of the precipitation considerably, causing it to be much more acidic. This acid rain not only adversely affects aquatic life, as mentioned, but is also implicated in fertility reduction among many species of fauna, not to mention the erosion of natural stone formations and human-made masonry structures. These ramifications correlate closely to places where coal is burned.

Transportation Vehicles

Cars, trucks, buses and heavy equipment are also instrumental in what causes acid rain. In particular, these conveyances (as well as tractors, steamrollers and excavating equipment) play a role in the release of nitrogen dioxide (NO2) into the air. Like SO2, NO2 can take a heavy toll on lung function and breathing if present in large enough accumulation, especially in particulate matter, and it lowers overall immunity. It is also proved to degrade nutrients in coastal habitats and also damage the vital ozone layer surrounding the earth.

Through much the same mechanism as SO2, NO2 combines with sunlight and water in the upper atmosphere to make rainfall (snowfall and fog, too) more acidic, upsetting the delicate balance necessary for life to thrive. Forests suffer from acid deposition, as do farms, pastures and human settlements. The internal combustion engines of vehicles act like the furnaces of a power plants. Although much smaller, there are many more of them and their role in what causes acid rain can not be ignored.

How Can We Prevent Acid Rain?

Burn Coal Cleaner

Knowing what causes acid rain points to the ways to counter it. There is good news concerning coal. Technology is mitigating some of its most noxious environmental effects. Between 2014 and 2016, power companies across the United States fitted their production facilities with scientific devices to conform to standards mandated by the federal Mercury and Air Toxics rule. As it turned out, these applications significantly lowered SO2, as well. In fact, between 2014 and 2016, SO2 output dropped by nearly 50 percent according to a sample under study. Less coal was utilized, also.

One such improvement is Dry Sorbent Injection, where hydrated lime is added to the flue gas to form a compound. From the compound, much of the acid gas and particulates are filtered out before the emissions are released. Another useful technology is Flue Gas Desulfurization. Also known as Wet Lime Scrubbing, this method adds water to magnesium treated limestone and sprays the gases rising through the stack with this cleansing slurry. Both procedures are effective, as the research underscores.

Energy Conservation

fluorescent lightbulb and incandescent lightbulbs

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Looking at prevention as a three-legged stool, the second leg involves expending less energy in general. Understanding what causes acid is a good first step. Still, it stands to reason if demand for energy is reduced, so will the supply be lessened, thereby diminishing the resulting pollution.

Conservation need not involve huge disruptions or inconveniences. Many people will leave lights on or computers powered on because they plan on using them later, forgetting that these idle minutes or hours consume valuable energy. Desiring a nice, cool house to walk into, they will likewise leave the air conditioning on for hours at a time. Turning devices and appliances off when unused can result in measurable savings in electricity.

Another effective area of conservation is vehicular use. Walking instead of driving – if the distance is reasonable – is an effective way to reduce emissions from exhaust. Still, others are carpooling, public transportation and combining trips for greater efficiency. Of course, the trusty bicycle should never be forgotten.

Alternative Energy Sources

Retrofitting smokestacks and stewarding energy responsibly go a long way toward the goal of lower acidic emissions. Looking farther into the future, however, means considering other sources for energy production. Some alternatives like nuclear power and natural gas are already in use, though each comes with different environmental concerns.

Interestingly, renewable supplies like wind, solar rays and biomass are shown to generate more power than previously thought. Indeed, the United States set a goal of 20 percent electricity from wind by 2030 given the productive performance of turbines.

Moreover, anaerobic digesters now efficiently extract methane from livestock manure, creating energy that not only powers farming operations, but also begets a surplus that is sold back to the utility grid. Consumers the world over, of course, will attest to the energy savings from solar panels. Converting photons from the sun into direct current, these receptors bypass carbon emissions and shave dollars off of utility bills.

Final Thoughts

Acid rain is evidence of an atmospheric imbalance: too much chemical matter occupying the air we breathe. Fortunately, we have the capacity to correct that balance and bring progress into harmony with the natural world. By burning coal cleaner, using electricity more efficiently and exploring other renewable forms of energy, we can neutralize those underlying facts of what causes acid rain.

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