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Health effects of air pollution on humans

World population emits huge amount of air pollutants every day, and this negatively affects our health. These emissions increase every year, threatening the planet and one of our most important sources of life, the air.

Air pollution consequences on the environment are well-known, and if you still want to know more about it check out or posts on this topic. However, it is little known that molecules that form air pollutants have serious impact on our well-being, as these affect several parts of our organisms.

It doesn’t matter how healthy you are when it comes to air pollution. However, sensitive groups such as children, elderly and people with respiratory or heart diseases may experience stronger symptoms and health effects.

Respiratory problems

Since our respiratory system is based in the interaction between our body and external air, it is obviously highly affected when it comes to breathing air pollution. Short-term exposure to air pollution may drive to the following symptoms:

  • Eye and nose irritation
  • Chest pain
  • Pneumonia
  • Bronchitis
  • Asthma
  • Emphysema
  • Worse respiratory illnesses such as bronchitis, asthma or emphysema.
  • Coughing or wheezing
  • Throat irritation
  • Nose bleeding
  • Dizziness
  • Weakness
  • Headache
  • Confusion
  • Fatigue
  • Nausea
  • Airway inflammation
  • Reduce lung function
  • Harm lung tissue
  • Shortness of breath (dyspnea)
  • Decrease the capacity to perform exercise
  • Premature mortality due to cancer or respiratory disease
  • Kidney failure
  • Male reproductive problems
  • Depression
  • Diarrhea

Long-term exposure to air pollution can cause consequences of suffering the health issues mentioned above stronger, they can even become chronic illnesses. Apart from those, other health problems in cases of constant exposure to air pollution are memory loss, movement problems, cardiovascular and neurological issues or even dead.

Cardiovascular and heart problems

If the pollutants inhaled have the capability to penetrate deeply enough into the human body to reach the bloodstream, consequences may turn into a huge amount of health problems. Moreover, the person will experience fast and direct effects since it reduces the amount of oxygen arriving to organs, or in other words, worse quality and less blood production.

Mobility issues, muscular problems, high blood pressure or heart diseases can be diagnosticated in cases of lead or carbon monoxide poisoning. Other important pollutants directly related to the cardiovascular system are sulfur dioxide (SO2) and nitrogen dioxide (NO2).

Neurological and birth problems in kids and other issues in adults

As mentioned above, children are more vulnerable to air pollution effects, such as anemia or behavioral problems. Mothers breathing high concentrations of polluted air during the pregnancy reach the fetus and experience issues like low birth weight or premature birth. Moreover, it can carry future consequences, for example permanent neurological problems (like learning deficits and lowered IQ) or slow development of normal childhood behaviors (like the use of words and talking).

Inhaling airborne particles also affects the neurological system of adults, for example increasing the risk of alzheimer and damaging or weakening the immune system. On the other hand, breathing volatile organic compounds (VOCs), is related to liver, kidney and central nervous system damages.

Skin issues

Air pollution can also damage your skin in several ways. However, its influence is not directly related since skin problems are given by the interaction between human-beings and environmental adverse conditions due to air pollution.

We may suffer skin cancer or premature aging skin because of ultraviolet sunlight rays high exposure, driven by the ozone layer depletion. Furthermore, skin irritation can be experienced when bathing in eutrophic water, if the water contains certain kinds of algaes. Both events result from air pollution emissions to the atmosphere and its posterior indirect effect on humans and the environment.

Sources of health effects of air pollution

Those evidence and effects in the human body can be given by adverse environmental conditions or either airborne pollutants:

  • Smog: Since its gases-particles composition makes it easy to penetrate deeply in the body.
  • Ozone layer depletion, global warming and climate change: Exposing ourselves to more ultraviolet sun rays that can directly damage our skin and worse the air we breathe, with wildfires smoke for example.
  • Sulfur dioxide (SO2) and Nitrogen oxides (NOx): The main components of acid rain. They can also react in the atmosphere in order to become more harmful pollutants, in particular nitrogen dioxide (NO2).
  • Carbon monoxide (CO): As it reduces the amount of oxygen that can be transported in the bloodstream.
  • Lead (Pb): Once it is inhaled, it is placed on the bloodstream and the bones involving almost every organ and system in the human body.
  • Ozone (O3): This gas become so toxic at ground levels.
  • Particulate Matter (PM): The smallest the particle is, the deeper it may penetrate into our organism, even to the bloodstream.
  • Volatile Organic Compounds (VOCs): Especially highly concentrated indoors since its emissions can be produced by a big amount of daily use gadgets.
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Effects of air pollution on the environment: animals, plants and ecosystems

Human activities have increased the amount of pollutants introduced in the air, that have direct and indirect effects in almost every ecosystem. Air pollution can lead to harmful consequences for living organisms through the inhalation of pollutants adverse weather conditions and others.

How does air pollution affect animals’ health?

No matter what their size is, air pollution affects almost every species on this planet. The most common health effects on animals are respiratory problems, which is totally obvious since they have similar respiratory systems to humans. Wildlife is prone to suffer same symptoms and diseases than humans. Specifically, lung tissue is very commonly affected on animals after breathing polluting gases or particles.

Most common symptoms and problems animals may suffer are:

  • Smog is composed of particles and gases, what makes it easy to penetrate deeply into the body, damaging the lungs and causing respiratory problems. Toxic environments are created with hard breathing adaptability. Furthermore, pollutants such as carbon monoxide can also lead to huge respiratory issues on animals.
  • Despite eutrophication influence is mainly to the ecosystem, due to certain toxic algae production some animals can suffer symptoms like skin irritation or health problems if drinking it.
  • Neurological issues on vertebrates because of lead accumulation on soils and its effects on plants.

How does air pollution harm plants and vegetation?

Air pollution has a lot of influence on vegetation by attacking its growth sources, such as airborne molecules, soil minerals or directly its organisms. Depending on the particular pollutant or environmental pollution conditions, main effects can be:

  • Smog, as well as particulate matter high concentrations, reduce the amount of sun rays arriving to plants, denying or slowing plant growth. This kind of air pollution damages forests and crops, especially vegetables such as soybeans, wheat, tomatoes, peanuts and cotton.
  • Ozone layer depletion increases the amount of UVB arriving to plants, and despite being prepared and adaptable to increasing levels of UVB, it can cause problems and modifications like form changes, nutrients distribution, developmental phases timing and secondary metabolism.
  • Forest and plants can also be harmed by acid rain since it damages tree’s leaves, robs the soil of essential nutrients and makes it hard for trees to take up water. All these issues imply growth and photosynthesis difficulties and more vulnerability to insects, diseases or bad weatherHigh concentrations of SOx are also harmful for vegetation foliage and growth, and can contribute to formate acid rain. Ozone also produce similar symptoms, especially during the plants growing season.
  • Lead can accumulate on soils for a long long time (hundreds or even thousands of years) and by combination with other metals it can inhibit photosynthesis, what implies growth and survival issues for the surrounding vegetation.
  • Nitrogen is essential for plants nutrition, but high levels of nitrogen dioxide or nitrogen monoxide pollution damage their lives.

How changes in ecosystems affect the fauna and flora?

Last but not least, air pollution may lead to harm an ecosystem as a whole and not only a particular organism from it. Some clear examples are:

  • Marine ecosystems may experience high temperatures and exposure to UVB, reducing survival rate of phytoplankton and damaging early developmental stages of fish, shrimp, crab, amphibians and other marine animals. These effects are the result from the ozone layer depletion.
  • Global warming is changing some ecosystems faster than the capability of animals and plants to adapt, leading to possible extinction of a huge amount of species. For example, ice sheets inhabited by polar bears are disappearing, (as it was said) warming oceans, more extreme weather conditions, etc.
  • Due to the rising amount of carbon dioxide emissions and acid rain generation, the surface of oceans and water bodies has increased its acidity. This phenomenon is called ocean acidification and can lead to harmful consequences, such as depressing metabolic rates in jumbo squid, depressing the immune responses of blue mussels, and coral bleaching. Furthermore, ocean and lakes acidification makes water toxic to crayfish, clam, fish, and other aquatic animals. However, it can be good for some species as a trade-off, such as sea star, which increases its growth rate with highest water acid levels.
  • Eutrophication, formed by phosphorus and nitrogen concentrations in water bodies, can even change the entire ecosystem from water to land (in extreme cases). Toxicity of the water, reduced amount of oxygen in deeper layers and difficult adaptability to the new substances may cause several damages into indigenous fauna and flora, leading to their reduction or even extinction.
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Air pollution effects: Smoke + Fog = Smog

What is smog?

Smog is an air pollution phenomenon that can be defined as the combination of various gases with dust and water vapor. In other words, smog is a yellowish or blackish fog composed of nitrogen oxides, sulphur oxides, ozone, smoke and dirt particles. This kind of visible air pollution was originally named in the early 20th century as a mixture of the words smoke and fog.

Types of smog

Depending on its origin and composition, there are 3 types of smog:

  • Volcanic smog is composed by oxygen, moisture, sunlight, particles and gases released from a volcano eruption. This type of smog is commonly seen in the Hawaiian Islands, as the Kilauea volcano has been erupting every day since 1983.
  • Photochemical smog is the most popular kind of smog nowadays. It is formed by nitrogen oxide, hydrocarbons and sunlight.
  • Sulfurous smog is originated when a high concentration of sulfur oxides are released into the atmosphere. It is also known as “London smog”, place where it is prevalent.

What causes smog?

Smog is formed when gases (for instance, ground-level ozone) and airborne particles react in the air with heat and sunlight.

Some of these pollution gases, called precursors, drive to ground-level ozone and particle formation, thanks to a sequence of photochemical reactions. Precursors gases are: volatile organic compounds (VOC), sulphur dioxide (SO2) and nitrogen oxides (NOx).

Apart from vehicles exhaust systems and its combustion of fossil fuels, smog-creation gases are also produced by coal fires and volcano eruptions.

However, smog usually appears in dense traffic situations and with optimal weather conditions to chemically react: high temperatures, calm winds and sunshine.

How smog affects the environment and humans health?

Since smog is composed by very tiny particles and gases, it can penetrate deeply into our bodies, specifically into the lungs of both animals and humans. A lot of species and green life are killed by smog due to the few adaptability to breathe purely in such toxic environments.

Smog exposure can drive to respiration problems such as breathing passages, decrease lungs working capacity, shortness of breath, pain when inhaling deeply, wheezing and coughing. Other respiratory issues or illnesses also related to smog are pneumonia, cold, chest pain, inflammation in lungs tissues or even premature death due to cancer or unknown respiratory diseases.

Eye and nose irritation are usual symptoms of smog exposure, drying out the protective throat and nose membranes and interfering with the body’s ability to fight infection and possible illness.

Furthermore, some studies have proven it also can drive to increase alzheimer probability, low birth weight or other birth risks. Hospital admissions and respiratory deaths often increase during periods when ozone levels are high. Moreover, smog can cause visibility problems for drivers and thus increase the danger of having a car accident.

Sensitive groups can suffer more intense symptoms and effects, this is why it is recommended for them to avoid any kind of exposure. This group at greater risks is formed by elderly, children and people with respiratory or heart problems, such as asthma, bronchitis or emphysema.

Levels of unhealthy exposure

Ozone is the most risky air pollutant in smog. According to the U.S. Environmental Protection Agency (EPA) and its Air Quality Index, 8 hour average ozone concentrations can be classified as:

  • Unhealthy for sensitive groups: 85 to 104 ppbv
  • Unhealthy: 105 to 124 ppbv
  • Very unhealthy: 125 to 404 ppbv

On the other hand, smog can cause harmful effects to the vegetation and the environment as well, denying plant growth, damaging forests, crops and vegetables, such as soybeans, wheat, tomatoes, peanuts and cotton.

What you can do to prevent smog?

When smog appears, you can only protect yourself with a face mask or staying indoors. To avoid these situations you can embrace some practices in order to prevent smog formation:

  • Change your car habits:
    • Drive less to cut down emissions.
    • Maintain your car to make it work properly.
    • Fuel up in cooler temperatures.
    • Purchase a hybrid or electric vehicle.
  • Change your consumption habits:
    • Avoid high VOC products, not only for smog prevention but also to have a good air quality indoors.
    • Avoid gas-powered yard equipment.
    • Buy local to reduce transport emissions.
    • Be energy efficient in your home.
  • Taking a stand:
    • Don’t support organizations that have poor environmental practices.
    • Promote your stance and what are you doing to solve the problem with your closest family and friends and even in Social Media.
    • Contact local politicians and business leaders.

Areas affected by smog

Smog is not only taking place in particular places, it can be formed wherever pollutants are emitted and in other areas where pollution has been transported by wind flowing.

However, there are some cities or places where smog is usual and can become a real nightmare for inhabitants:

  • Canada
  • Delhi, India
  • Beijing, China
  • London and other areas in the United Kingdom
  • Mexico City, Mexico
  • Santiago, Chile
  • Tehran, Iran
  • Los Angeles and the San Joaquin Valley, United States
  • Ulaanbaatar, Mongolia
  • Southeast, Asia
  • Pakistan

The Great Smog of London 1952

Otherwise, the worst case of urban smog happened in London from Friday 5 to Tuesday 9 of December 1952. It was called the Great Smog of London (and the Great Smog of 1952 as well) and it caused more than 4.000 deaths and 100.000 illnesses during that period, most involving respiratory problems. Furthermore, recent studies have proven that over 6.000 people more passed away on the following months.

Among a lot of reasons, it was originated because of low temperatures during that winter, fact that made Londoners burn more coal to warm themselves. Later an anticyclone settled over a windless London, which caused a temperature inversion and favoured smog to be formed and persistent over the city.

What is a smog check?

Smog Check inspections are designed to identify vehicles with excess emissions. For instance, in California (United States), there is a Smog Check Program that has become very popular and it is an important part of the improvements made to control air pollution.

Despite other countries do not have smog tests or stations by themselves, “smog emissions” are checked every time your car gets its circulation license and inspection sheet.

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Air pollution effects: Ozone Layer Depletion

What is the ozone layer?

The Ozone (with chemical formula O3) is a molecule composed of three atoms of oxygen, reason why it is also known as trioxygen. It forms a natural belt or “shield” in the upper atmosphere (at 20 km to 30 km above Earth), also called stratosphere.

This ozone layer protects us from solar ultraviolet (UV) radiation. For this reason, it is considered one of the primary greenhouse gases in the atmosphere, alongside water vapor, carbon dioxide, methane and nitrous oxide.

These greenhouse gases absorb and emit radiant energy in order to maintain the average temperature of Earth’s surface in about 15°C (59 °F). Without these gases, the temperature would be about -18°C (0 °F), and life would be less viable.

What is the ozone layer depletion?

Since the beginning of the Industrial Revolution the emissions of carbon dioxide to the atmosphere have massively increased, partially destroying this protection layer and driving to the ozone layer depletion, commonly known as “the ozone hole”.

It is one of the most serious problems faced by our planet earth. Without this protective layer preventing the entrance of ultraviolet radiations with high energy electromagnetic waves, our planet would suffer some issues, such as global warming, and the humanity would have serious difficulties to survive.

If you would like to have a look at the ozone layer right now or last months, you can take a look to NASA’s ozone map.

Causes of the destruction of the ozone layer?

About 80% of the total ozone layer depletion is due to the production and emission of chlorofluorocarbons (CFCs). At stratospheric levels, CFCs convert into chlorine, which reacts with ultraviolet rays to destroy ozone on a massive scale.

This conversion from CFCs to chlorine is faster at lower temperatures, and explains why the ozone layer above Antarctica has been extremely damaged. In Antarctica the hole in the ozone layer can be clearly seen growing since mid-1980s.

Other air pollution compounds contributing to the ozone layer reduction are hydrochlorofluorocarbons (HCFCs) and volatile organic compounds (VOCs). Both, maintain stable at lower atmospheric levels and react with sun rays at the stratosphere, just as CFCs do. The emissions of these gases come from aerosols, refrigerants, industrial processes, and obviously from vehicles combustion engines.

Effects of the ozone hole to the environment and health

When high energy electromagnetic waves reach the Earth’s surface, both the planet and humans are exposed to several harmful effects due to the ozone layer depletion.

For humans, direct exposure to UV rays can lead to:

  • Skin cancer such as melanoma, basal cells or squamous cell carcinomas.
  • Premature aging and other skin damage.
  • Eye damage such as cataract problems, photokeratitis or snow blindness.
  • Damage or weak the immune system.

In plants, despite being prepared and adaptable for incrasing levels of UVB, ozone layer depletion can cause problems such as: form changes on how nutrients are distributed, on  developmental timing phases and on secondary metabolism.

On marine ecosystems, exposure to UVB reduce survival rates of phytoplankton and harm early developmental stages of fish, shrimp, crab, amphibians and other marine animals. Furthermore, short wave ultraviolet B (UVB) sun rays can also alter terrestrial and aquatic biogeochemical cycles.

Ozone layer depletion is obviously one of the main reasons that contribute to global warming, applying over Earth’s surface a greenhouse effect and increasing its temperature. Actions that warm our planet’s surface contribute to climate change, with direct and indirect effects in almost all ecosystems and organisms. This is why the ozone layer is so important, for the Earth, for us!

Ozone layer depletion prevention

To sum up, destructing the ozone layer does not help anyone, we are putting everything and everyone in danger!

Despite the creation of some international laws and agreements to preserve the environment and reduce CFCs emissions (such as Montreal Protocol, Kyoto Protocol, The Paris Agreement and many other national laws), everyone needs to take part and change some habits or with different daily practises. Here are some examples:

  • Buying and using recycled products.
  • Saving of energy:
    • Change your light bulbs to CFL
    • Use less heat and air conditioning
    • Buy energy-efficient products
    • Use less hot water
    • Use the “off” switch
  • Reducing fossil fuels emissions by using public transport.
  • Plant a tree (or two!).
  • Spread awareness and encourage others to make a change.
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Air pollution effects: Haze Weather

What does haze weather mean?

Haze is an atmospheric phenomenon where visibility of the sky is reduced due to the high presence of smoke, dust and other airborne particles, giving the sky a bluish or brownish color. According to the World Meteorological Organization, horizontal obscurations can be classified among fog, ice fog, steam fog, mist, haze, smoke, volcanic ash, dust, sand or snow.

Haze measurement

The coefficient of haze, which is also known as smoke shade, is a measurement of visibility interference in the atmosphere and it is calculated by the absorbance formula: COH = log10 (I1 / I0).

However, haze is usually measured using the Pollutant Standards Index (or PSI), which is a type of air quality index that indicates the level of pollutants in the air. It may differ depending on the country since other indices are used worldwide, such as Air Quality Health Index or Air Pollution Index. Some examples of countries using PSI as an indicator of air quality are the United States (until 1999, when it was changed for Air Quality Index) and Singapore.  

Singapore’s National Environmental Agency (NEA), indicate PSI with a number between 0 and 500. If air quality reaches levels over 100 PSI, population may notice it and can suffer health effects. As a point of interest, Singapore has the 3-hour PSI reading record with 401 (21st June 2013).

Causes and effects of haze

Haze particles emissions come from sources such as farming (ploughing in dry weather), traffic, industry, and wildfires. Cars combustion engines or industrial pollution emit sulfur dioxide particles (SO2) that generate haze, which after chemically reacting in the atmosphere with other compounds can become smog or acid rain.

Wind can carry haze from one country to another, like what happened in Malaysia in 2013. Despite Arctic has not enough emissions to pollute its own air, during springtime that region suffer a reddish-brown haze due to air pollution emissions mainly coming from Asia. The most characteristic feature of Arctic haze is the ability of its chemical ingredients to persist in the atmosphere for an extended period of time, in comparison with other pollutants.

In Indonesia it is typical to burn trash because of the lack of cleaning services, or plantations, in order to clean land during dry weather. Especially in the islands of Sumatra, Kalimantan and Riau, fires are more regular, what made these places main sources of haze.

In 2013, due to indonesian forest fires, Kuala Lumpur (Malaysia’s capital) suffered extreme haze weather conditions. As Indonesia is considered the world’s third largest greenhouse gas emitter, in 2014 after what happened with Malaysia it also became part of ASEAN Agreement.

Other laws or agreements to preserve the environment and solve visibility problems are: the Interagency Monitoring of Protected Visual Environments (IMPROVE) program as a collaboration between US EPA and the National Park Service, or the Clean Air Act also implemented by US Environmental Protection Agency (EPA).

ASEAN Agreement

In order to reduce haze pollution in Southeast Asia, the Association of Southeast Asian Nations signed in 2002 an environmental agreement. In 2014 this agreement was ratified. Member states of the agreement are: Malaysia, Singapore, Brunei, Myanmar, Vietnam, Thailand, Laos, Cambodia, Philippines and Indonesia.

What is the difference between haze, fog and mist?

The three of them imply reduced visibility because of weather conditions (for fog and mist) or air pollution (for haze). This is the main difference, while fog and mist are formed by the suspension of water droplets, haze is made of extremely small and dry airborne particles.

Fog is the name given to resulting visibility of less than 1 km, according to the international agreement for aviation purposes. However, in weather forecasts for the general public it is understood as less than 180 meters of visibility. On the other hand, mist is exactly the same phenomenon as fog lowing its density and increasing visibility to 1 km or more.

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Air pollution effects: Global Warming

What is global warming?

Global warming can be defined as an increase in the average temperature of the Earth due to air pollutants, which collect sunlight and radiation and produce the greenhouse effect. This pollution layer avoids the reflection of sun rays by Earth’s surface towards space, which raise the temperature in our planet among a lot more consequences.

It is a real problem since statistics and evidence are there. According to NASA’s data:

  • Carbon monoxide levels in the air are the highest in 650.000 years, concretely up to 408 ppm (parts per million).
  • 17 out of the 18 warmest years in history (which have been recorded) have taken place after 2001. Global temperature has increased 1°C (1,8°F) since 1880.
  • Arctic ice minimum levels have decreased 13,2% each decade. In 2012, Arctic summer sea ice shrank to the lowest extent on record.
  • Satellite data show that Earth’s polar ice sheets are losing mass at speed of 413 gigatonnes per year.
  • Sea level is currently increasing 3,2 millimeters per year.

Causes of global warming

The main cause of global warming, according to most climate scientists, is the greenhouse effect. Greenhouse gases absorb heat and re-emit it in all directions warming up the lower atmosphere and the Earth’s surface.

Burning of oil and fossil fuels, which mainly come from sources such as vehicles combustion engines and carbon industries, emit huge amounts of carbon molecules to the atmosphere, where they react with oxygen to create carbon dioxide (CO2). More sources of global warming contributing to create that pollution layer “in charge of microwaving the Earth” are soot and aerosols, among many others.

Which are the greenhouse gases?

These gases can be classified in two groups depending if they react to changes (physically or chemically) (“feedbacks”) or not (“forcing”). Greenhouse gases are:

  • Water Vapor (H2O): The most abundant greenhouse gas. It performs as feedback: the warmest the Earth is, more water vapor will be found in the atmosphere (clouds and precipitation).
  • Nitrous oxide (N2O): Human-made activities such as soil cultivation, use of fertilisers, fossil fuel combustion, nitric acid production or biomass burning.
  • Methane (CH4): An active, but limited greenhouse gas emitted by human and biological sources like agriculture or ruminant digestion associated to livestock.
  • Carbon dioxide (CO2): Although produced naturally by respiration or volcano eruptions, carbon dioxide emissions have become an environmental problem due to anthropogenic sources. Since Industrial Revolution, activities such as industrial operations, deforestation or burning of fossil fuels, among others have massively increased the emission of this greenhouse gas.  
  • Chlorofluorocarbons (CFCs): synthetic compounds produced by industrial activities and controlled by some governments due to its strong effects related to the ozone layer depletion.

Global warming environmental effects: Climate change

Mainly, global warming implies the worst of the air pollution environmental effects: Climate change! By warming up the surface of our planet, we get an impact almost worldwide.

Some of the current evidence of climate change are:

  • Ice declining and sea level rising:
    • Ice sheets slip: The warmer the planet is, faster the ice will thaw.
    • Glacial shrink, especially in places such as the Alps, Himalayas, Andes, Rockies, Alaska and Africa.
    • Less snow covering the top of mountains.
    • Sea level rise at current speed of 3,2 millimeters per year, which in 50 years mean coastline will have risen over 15 centimeters.
    • Downturning the thickness and extension of Arctic sea ice.
  • Extreme weather events:
    • Extreme events such as hurricane Katrina (2005), which hit New Orleans and other american cities of Louisiana and Florida. In this section plagues, more and stronger rains, intense heat waves, floods, and others are also included.  
  • Ecosystem changes:
    • Warmer global temperature: As already mentioned, since the 19th century the average temperature of the planet has increased by 1°C (1,8°F).
    • Warming oceans: oceans have collected this increased heat within the top 700 meters.
    • Ocean acidification:  The acidity of surface ocean waters has increased by about 30% due to humans activities emitting carbon dioxide into the atmosphere.

However, this does not end here. The effects will continue to grow and environmental impact will rise over the years:

  • Temperatures will continue increasing.
  • Extending frost-free and growing seasons for crops.
  • Precipitation patterns will be affected.
  • Changes in natural habitats that will cost the extinction of a huge amount of plants and animals.
  • More droughts and heat waves.
  • More intense and stronger hurricanes.
  • Sea level will rise from 30 to 120 centimeters by the end of 21th century.
  • Arctic won’t have ice anymore.

Health effects of global warming

Despite climate change has direct health effects in humans, most of the problems or issues it causes are due to environmental alterations. Heat waves, natural disasters, breathing poor air quality and spreading diseases are just some examples.

Some groups such as kids or elderly are more vulnerable to illness or death due to these global warming consequences. However, it affects differently depending on the region and the capacity of each country to adapt to changes.

Global warming will also affect crops, livestock, fisheries and others by reducing yields, seasonal and weather changes, the need of using more pests, etc. Furthermore, drinking water will become harder to find, less availability and of less quality.

How to stop and prevent global warming?

Changing your daily routines is not easy, but if you expect a future we need to make the effort and change some habits. It is not only a government’s duty, it is in our hands!

Some possible solutions to reduce global warming are:

  • Investing in renewable energies for our homes, businesses, means of transportation, etc.
  • Not use fossil fuel electricity anymore.
  • Change our food production habits in order to prevent deforestation and forest degradation, as these emissions represent the 30% of the world’s heat trapping emissions.
  • Improving in nuclear power, so it has fewer pollution emissions.
  • Improve and apply new low-carbon and zero-carbon technologies.
  • Reduce water waste.

Each of our individual inputs will make a change and guide the planet to a better future. If we expect our leaders and politicians to make everything, the situation is not going to change. For example, US President Donald Trump said that “global warming is a hoax” years before the elections. If the president of one of the top countries in the world is not taking care of our planet, we need to make the difference throw individual efforts.

On the other side, there are countries aware of the problem that created alliances and agreements about global climate change over the years, such as The Paris Agreement (the latest UNFCCC agreement).

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Air pollution effects: Eutrophication

What is eutrophication?

Eutrophication is a word that comes from the greek, meaning well-nourished. It is phenomenon where high concentrations of nitrogen and phosphorus (present in pollutants) are involved with water in rains, rivers or seas.

This high concentration provokes an enrichment of water by nutrient salts that cause structural changes to the ecosystem. The visual ones are massive production of algae and aquatic plants. The green coloured algae is very common in lakes and ponds, and it is only caused due to this reaction of air pollution. On the other side, the harmful ones are depletion of fish species and water deterioration.

It may not look dangerous, but eutrophication is a harmful environmental process, especially when it is empowered by human activities, which is called cultural eutrophication. The changes in the water body may depend on the usage of fertilisers, the discharge of waste water into water bodies and the reduction of its self purification capacity.

Trophic Classifications of a Water Body

The trophic or nutritional state of a water body is determined by the amount of useful nutrients dissolved on it, either if they are produced naturally or human-made. Four nutritional stages are found:

  • Oligotrophic: An oligotrophic lake or water body has low nutrient content, which means low productivity. It has high quality drinking water and it is usually found in cold environments. It facilitates life for aquatic species who need cold and well-oxygenated water.
  • Mesotrophic: It has medium level of nutrients and its productivity is also intermediate.
  • Eutrophic: It is a stage that can be produced either by humans or natural causes. At the beginning, it increases fauna and flora generation, but when vegetation growth expand massively and fauna suffers respiration and survival problems.
  • Hypereutrophic: An excessive growth of vegetation, especially seaweed, on the water surface that creates dead zones underneath. Water visibility is poor and hypereutrophic lakes are characterized for having more than 100 micrograms/liter of phosphorus and over 40 micrograms/liter of chlorophyll.

Eutrophication process: causes and effects

Despite eutrophication is a natural and biological process, it can speed up due to human activities such as:

  • Usage of fertilisers.
  • Massive production of livestock, birds and fish.
  • Treatment plants.
  • Nitrogen oxides (NOx) and sulfur oxides (SOx) emissions.

Deforestation and leaving abandoned forest and wood residues, are also main sources of eutrophication in forest lakes, cutting down water quality and causing huge environmental issues.

These causes can be divided into 3 groups: point sources where the nutrient waste travels from a particular source to water (such as wastewater effluent or untreated sewage); nonpoint sources coming from ill-defined and diffuse sources (such as runoff from abandoned mines or from pasture and range); or others.

The most important pollutants to control in order to prevent eutrophication are the mentioned phosphorus and nitrogen. According to their levels in the water body, they may provoke more or less harmful effects. For instance, some eutrophication consequences are:

  • Abundance of particulate substances such as phytoplankton, zooplankton, bacteria, fungi and debris.
  • Abundance of inorganic chemicals that can generate harmful substances in the drinking water treatment plants.
  • Abundance of organic substances that form complex chemical compounds preventing and difficulting the usual purification processes.
  • Creation of algae that gives the water disagreeables colours, odours and flavours.
  • Quality fish reduction or extinction in the affected area.
  • Toxic algae production that can drive to health problems to humans and animals at drinking it.
  • Certain algae created can produce skin irritation if bathing.
  • Reduction of oxygen concentration, especially in the deeper layers of the lake.

However, the most impactful (and weird) effect of eutrophication is the sedimentation process. At increasing its biomass, even great lakes can become solid land after some time of eutrophication due to pollution problems and massive algae formation.

Prevention of eutrophication

Since eutrophication reduction strategies are expensive and ineffective, the best way to protect an environment and its organisms is trying to prevent the phenomenon. Some of the best prevention methods for water pollution are:

  • Installing tertiary treatment systems to reduce nutrient concentrations in wastewater treatment plants.
  • Limit the production of waste water by using other practices in animal husbandry.
  • Application of effective filter ecosystems to remove nitrogen and phosphorus in the runoff water.
  • Downsizing the amount of phosphorus in detergents.
  • Fertilisation planning and slow release fertilisers usage to rationalize agricultural techniques, or changing these techniques to become organic.

Cultural eutrophication is a complex issue that can only be solved, or at least improved, by the collaboration of scientists, politicians, citizens and environmental organizations. Only together we will be able to prevent new cultural eutrophication cases and to restore some aquatic communities.

The most known law to protect and prevent water pollution in US is the Clean Water Act (CWA) of 1972, which required EPA to establish water quality criteria for the Great Lakes addressing 29 toxic pollutants with maximum levels that are safe for humans, wildlife, and aquatic life. It was first created in 1948 as The Federal Water Pollution Control Act, and over the years it has received some adjustments to improve and update it.

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Air pollution effects: Acid Rain

What is acid rain?

Acid rain, or acid deposition, can be defined as any form of precipitation with high levels of nitric and sulfuric acids. It can occur in the form of snow, fog and even dry materials that settle to earth.

Types of acid deposition

  • Wet deposition: It is “the image” that comes to your mind when you imagine acid rain. More in detail, is when any kind of precipitation (rain, snow, fog, hail, sleet or dew) removes acids from the atmosphere and delivers it to the Earth’s surface.
  • Dry deposition: It occurs when particles and gases stick to the ground, vegetation, buildings or other surfaces. Between 20 and 60% of total acid rain is dry deposition, but it depends on the amount of rainfall received (the less water deposited over the year, the higher ratio of dry deposition).

PH of acid rain

PH scale is a logarithmic scale used to specify the acidity or basicity of an aqueous solution. It goes from 0 (acidic) to 14 (alkaline), with 7 as neutral point. Some common examples of pH are: battery acid (pH = 0), distilled water (pH = 7), blood (pH = 7,4) or liquid drain cleaner (pH = 14).

Normal or clean rain is between 5 and 6 pH, especifically 5,6, while acid rain has a pH closer to 4, generally between 4,2 and 4,4.

These levels are not enough acidic to harm our skin like people commonly imagine. If lemon juice or vinegar don’t harm us and have a pH of 2, acid rain is not going to cause any health problems in our skin if we are not usually exposed to it.

What causes acid rain?

Most acid rain is caused by human activities, especially when people burn fossil fuels, the main components of acid rain, sulfur dioxide (SO2) and nitrogen oxides (NOx, the combination of NO and NO2), are released into the atmosphere.

Winds and air currents can carry and spread these gases over thousands of kilometers. Then, some of their components are deposited and react with water, oxygen, and other substances to form sulfuric and nitric acid.

Major sources of sulfur dioxide and nitrogen oxides are anthropological:

  • Electric power generators using coal release into the atmosphere between ⅔ and ¼ of SO2 and NOx total emissions, respectively.
  • Vehicles and heavy equipment because of the burning of fossil fuels.
  • Manufacturing, oil refineries and other industries.

Just a little part of the total SO2 and NOx emissions are released naturally by volcano eruptions, electrical activities in the atmosphere (like lightning or acidic deposits in glacial ice), among others.

How is the chemical process of acid rain formation?

For those who are interested in knowing the stoichiometric equations or formula for the formation of sulfuric acid, here it is:

  • Burning of fossil fuels release sulfur dioxide: S (in coal) + O2 → SO2
  • Sulfate ion is made from the oxidation of sulfur dioxide: 2 SO2 + O2 → 2 SO3
  • The reaction between hydrogen atoms and sulfate ion creates sulfuric acid: SO3 + H2O → H2SO4

Effects of acid rain on humans and the environment

Acid rain is one of the air pollution phenomena that practically only affects the environment, as it does not affect humans directly. Wind can spread easily sulfur dioxide and nitrogen oxides to long distances, so effects can show up far away from its original sources.

After falling, acid rain enters water systems of runoff and sinks into the ground. This can make water toxic to crayfish, clam, fish, and other aquatic animals. The rest of the food chain, including non-aquatic species such as birds, are often affected as well. Furthermore, it not only pollutes lakes or little water concentrations, acid rain also contributes to ocean acidification, making it difficult for coastal species to survive.

Acid rain also harms forest and vegetation damaging trees’ leaves, releasing harmful substances into the soil (such as aluminium), robbing the soil of essential nutrients and making it hard for trees to take up water. Affected trees have growth difficulties due to the lack of nutrients and minerals, it makes it harder to photosynthesise properly or makes them more vulnerable to insects, diseases and bad weather.

The erosion process by wind, water, snow and ice is stronger when it is complemented with acid rain. It will help this natural process to become quicker, and can affect statues, building, vehicles, pipes and cables.

Despite acid rain has no direct effects on humans’ health, its components (SO2 and NOx) have it, causing heart and lung problems, such as asthma and bronchitis. As mentioned in other posts, sensitive groups such as kids, elderly or asthmatics will suffer harder symptoms.

How to prevent acid rain?

Designing cleaner power plants and using fewer fossil fuels, the number of pollutants that create acid rain could be reduced. Since a huge amount of emissions are human-made, governments should invest on finding new sources of power for industries and vehicles or at least control those vehicle emissions.

Furthermore, the damage done to lakes and rivers can be restored by adding powdered limestone to neutralise the water. This process is called liming, and despite being a continuous expensive treatment, it can restore the environment and its wildlife.