Have you ever wondered if acid rain can actually harm or kill you? Here we explore what effects, if any, acid rain can have on human health, and also answer some other common questions about acid rain relating to its effects on us.
Can acid rain kill you?
While acid rain can be incredibly detrimental for the environment and will kill many plants and animals over a long enough exposure, it won't directly hurt or kill you. In fact, according to the U.S. EPA, "walking in acid rain, or even swimming in a lake affected by acid rain, is no more dangerous to humans than walking in normal rain or swimming in non-acidic lakes".
Problems to human health relating to acid rain actually come from the pollutants that form acid rain in the first place -- sulfur dioxide and nitrous oxides. Other associated pollutants like sulfate and nitrate molecules can also harm you as well.
When these pollutants are airborne, there is a potential for you to inhale them into your lungs.
When exposure to this kind of particulate matter is acute enough, it can lead to a host of medical problems, such as increased risk and severity of heart disease and impairment of lung function, which can also result in diseases like asthma, bronchitis, and emphysema.
Where is acid rain most common?
Acid rain is, sadly, relatively common across the world especially in the North Eastern United States, Eastern Europe, and increasingly in rapidly developing nations like China and India.
Historically, in Europe, one particularly badly affected geographical area is the so-called "Black Triangle". Covering areas of the Czech Republic, Germany, and Poland, this area received very heavy bouts of acid rain during the 1970s and 1980s.
In parts of this area, entire forests lay dead or dying, and even railway tracks were seriously corroded by the acid rain. To combat this, strict regulations were enacted, notably, the 1979 convention on Long-Range Transboundary Air Pollution, which mandated, among other actions, cutting pollution emissions from coal-fired power stations.
These measures have since proved to be very effective and have significantly reduced acid rain in the region.
In the United States, caused by emissions from Midwestern coal-burning power plants, some parts of the northeastern U.S. and eastern Canada were badly affected by acid rain in the 1960s through the 1980s. It has been estimated that somewhere in the region of 90% of the freshwater streams in these areas are still heavily acidified today.
Thanks to regulations like the 1990 Clean Air Act, the effects of acid rain have fallen dramatically in the region. But recovery from acid rain damage takes time, and soil in these areas have only recently shown signs of stabilizing.
Since around the year 2000, levels of nitric and sulfuric acid in rain have been steadily increasing in certain Asian cities, such as Beijing and New Delhi. The rising demand for electricity, and the rapidly-growing manufacturing and steel production sectors are the main drivers.
While China and India do have some pollution control regulations, the rise in demand for coal-power in these nations will likely see acid rain being a problem in these countries for years to come. According to some studies, China has been able to drop their sulfur dioxide emissions by as much as 75% since 2007, but that of India has increased by 50%.
Can acid rain burn your skin?
Very strong acids can, and will, burn your skin on contact, and can even destroy some metals. But for this to occur, the pH of these kinds of acids needs to be very low, around pH 1.
Acid rain, on the other hand, is a comparably much weaker acid, and usually has a pH ranging from 4.2 to 4.4. Though lower pHs have been recorded in the past.
To put that into perspective, vinegar has a pH of about 2.2 and lemon juice about 2.3. Even the lowest recorded pH in acid rain was still only roughly as strong as vinegar or lemon juice.
That being said, you should avoid getting even mild acids in your eyes or other mucous membranes. If the pH is low enough, it could either irritate and sting your eye, or at high enough exposure, could cause significant damage to your cornea, potentially leading to vision impairment.
With acidity in the range of 4.2 to 4.4, acid rain is not strong enough to burn your skin. You might also be interested to learn that normal "clean" rain is also slightly acidic, usually having a pH of between 5 and 5.5.
In what ways does acid rain affect humans?
And so, without further ado, let's explore some of the effects of acid rain on human health. But, it bears repeating, the most serious effects on human health are not from acid rain directly, but rather, from the pollutants that cause it.
The following are exhaustive and are in no particular order.
1. Inhaling the pollutants that cause acid rain can cause serious lung diseases
Nitrous oxides and sulfur dioxides are key pollutants responsible for causing acid rain. They can have serious health implications if you are exposed to them in high doses, or consistently with lower doses over a period of time. Both can interact with the atmosphere to create fine particles of sulfates and nitrates which can travel over very long distances.
These particles are so fine, that they are also readily inhaled by humans and will travel deep into your lungs. Such particles can also easily make their way into indoor environments too.
These type of fine particulants are linked to serious health complications.
Many scientific studies have shown that elevated levels of these fine particles has a high correlation with increased illness and premature death from lung disorders like asthma and bronchitis.
Nitrogen oxides are also a key component in the formation of ozone, through interaction with volatile organic compounds (VOCs). Exposure to ozone can also have serious effects on human lungs, from inflammation to the development of emphysema.
2. These pollutants can also cause some serious heart diseases too
Nitrous and sulfur dioxides, as well as nitrate and sulfate products, can also lead to serious heart disease. Various studies have shown an association with sulfur dioxide and increased morbidity and mortality in humans and animals from cardiovascular diseases like ischemic heart disease, heart failure, and arrhythmia.
These studies have also shown that the mitochondrion of animal cells is the most sensitive cell organelle in the myocardium (muscular tissue of the heart) of animals exposed to SO2.
Sulfates also occur naturally and are a common component of "clean" water. Along with other salts and minerals that tend to dissolve in drinking water, they can help improve the taste of water. HIgh levels of sulfates in drinking water have been associated with laxative effects, or even diarrhea, which can, ironically, lead to dehydration.
Exposure to high levels of nitrates in drinking water have also been associated with serious illness and sometimes even death. In the body, nitrate converts to nitrite, which interferes with the oxygen-carrying capacity of blood. Symptoms, such as shortness of breath and blueness of the skin, can occur rapidly over a short period of time. Nitrates are also known to lead to to serious illnesses in infants.
3. Acid rain can seriously affect the food chain and human crops
One indirect effect of acid rains on humans is the potential damage it causes to the food chain. If serious enough, these rains could lead to famine, as plants and animals people rely on for food fail to thrive.
Acid rain affects plants, in particular, by leaching vital nutrients from the soil, releasing aluminum and other toxic metals, and by damaging the waxy cuticles of some plant leaves.
The pollution and damage sometimes impairs its ability to grow and survive in the long run. Sometimes though, lowering the pH of the soil can also kill plants directly if they do not have a high pH tolerance range.
While some common crops like apples, carrots, cauliflower, corn, and cucumber do prefer somewhat acidic soils (pH 5.5 to 6.5) if the pH drops too low they also may not grow or thrive.
Acid rain can also have serious effects on aquatic ecosystems in lakes and rivers. Phytoplanktons, for example, are particularly susceptible to low pH levels, and will readily die. As they are at the bottom of the food chain, the death of phytoplanktons can then lead to the collapse of the entire food chain.
Leaching of poisonous metals like aluminum, cadmium, and mercury from the soil by acid rain can also directly kill many aquatic species, especially gill-breathing ones. Again, this can lead to the collapse of entire food chains.
In short, Any serious effects on crops or animals can ultimately result in famine if the impact is serious enough.
There have even been some studies showing that acid rain from air pollution in one country can cause droughts in other countries too.
In summary, while acid rain is not necessarily harmful to humans directly, we have seen that the pollutants that create it, and its effects on the environment, have very real potential harmful effects on us and nature.
But, it's not all doom and gloom.
Increasing pressure on the industry to reduce and clean up their emissions has caused a reduction in acid rain in many parts of the world. It seems to many experts in the field, that some of the worst effects of acid rain could someday be a thing of the past.