FIRST ASSIGNMENT - Environmental impacts


One of the aim of life-cycle assessment, is to try to have a product perspective in order to consider environmental issues referred to the production process.
For the porpouse of obtening a good assessment of any kind of product, which starts from a raw material and finishes when it is useless, is necessary to look at the impact assessments. These impacts assessments are divided into three main levels: Characterisation, Normalisation and Weighting.
The first level is about the environmental impacts which may cause the product to the environment with emissions and waste, and also the negative effects to the living beings. There are three kinds of categories depending on the importance of the impact
• Global
• Local
• Regional

On this assignment, we focus on global and local impacts.

Greenhouse effect

The first global impact is greenhouse effect, as we know; the Earth has a natural temperature control system. Certain atmospheric gases are critical to this system and are known as greenhouse gases. Some of the solar radiation is absorbed by the atmosphere but most is absorbed by the land and oceans. The Earth's surface becomes warm and as a result emits infrared radiation. The greenhouse gases trap the infrared radiation, so the atmosphere becomes warmer, so a negative and dangerous effects is that the poles may melt, with all its consequences.
Naturally occurring greenhouse gases include water vapour, carbon dioxide, ozone, methane and nitrous oxide, andtogether create a natural greenhouse effect.
However, human activities are causing greenhouse gas levels in the atmosphere to increase. As we can see on the single diagram 1.1, the main human activities are deforestation; CFCs, used as refrigerants, propellants; nuclear factories; some farming practices and land-use changes increase the levels of methane and nitrous oxide; and petrol engines, that are in the transportation we use normally in our daylife.

Diagram 1.1
Human activities that make worse the greenhouse effect

Ozone depletion

First of all we need to know the importance of the ozone layer, which is a belt of naturally occurring ozone gas that serves as a shield from the harmful ultraviolet B radiation emitted by the sun.
Ozone is a highly reactive molecule that contains three oxygen atoms. It is constantly being formed and broken down in the stratosphere.

Today, there is widespread concern that the ozone layer is deteriorating due to the release of pollution containing the chemicals chlorine and bromine.
Chlorofluorocarbons (CFCs), chemicals found mainly in spray aerosols heavily used by industrialized nations for much of the past 50 years, are the primary culprits in ozone layer breakdown. When CFCs reach the upper atmosphere, they are exposed to ultraviolet rays, which cause them to break down into substances that include chlorine. The chlorine reacts with the oxygen atoms in ozone and destroys the ozone molecule. Based on the circular graphic 2.1, we can assess the importance of the human on the source of chlorineat the stratospheric (82%).
Such deterioration allows large amounts of ultraviolet B rays to reach Earth, which can cause skin cancer and cataracts in humans and harm animals as well. Extra ultraviolet B radiation reaching Earth also inhibits the reproductive cycle of phytoplankton that make up the bottom rung of the food chain. Biologists fear that reductions in phytoplankton populations will in turn lower the populations of other animals.

Graphic 2.1
It shows the proportion of chlorine due to human

Acidification

The first regional impact we are talking about is acidification, which is commonly associated with atmospheric pollution

The main envarionmental effect is acid rain, this phenomenon occurs when some gases react in the atmosphere with water, oxygen, and other chemicals to form various acidic compounds. Sunlight increases the rate of most of these reactions. The result is a mild solution of sulfuric acid and nitric acid.

Scientists discovered, and have confirmed, that sulfur dioxide (SO2) and nitrogen oxides (NOx) are the primary causes of acid rain. In the US, About 2/3 of all SO2 and 1/4 of all NOx comes from electric power generation that relies on burning fossil fuels like coal. You can get an idea with the pie chart 3.1, below these paragraphs.
Acid rain causes acidification of lakes and streams and contributes to damage of trees at high elevations and many sensitive forest soils. In addition, acid rain accelerates the decay of building materials and paints, including irreplaceable buildings, statues, andsculptures. Prior to falling to the earth, SO2 and NOx gases and their particulate matter derivatives, sulfates and nitrates, contribute to visibility degradation and harm public health, like respiratory and cardiovacular illness.
Diagram 3.2
Anthropogenic and natural sources
Chart 3.1
A US study, shows how the different human activities influence on SO2 and NOx emissions

Nutrient salt loads
Secondly, another common regional impact is nutrient salt loads, which is also called eutrophication.
This proccess occurs when the environment becomes enriched with nutrients. This can be a problem in marine habitats such as lakes as it can cause algal blooms.
Fertilisers are often used in farming and sometimes these fertilisers run-off into nearby water causing an increase in nutrient levels, some others sources which contribute to make worse this problem are sewage works, industry and residues from cities near the river or lake. These factors cause phytoplankton to grow and reproduce more rapidly, resulting in algal blooms. See picture 4.1.

This bloom of algae disrupts normal ecosystem functioning and causes many problems, for example use up all the oxygen in the water, leaving none for other marine life, this results in the death of many aquatic organisms such as fish and microorganism.
Furthermore the bloom of algae may block sunlight from photosynthetic marine plants under the water surface.
Finally, some algae even produce toxins that are harmful to higher forms of life. This can cause problems along the food chain and affect any animalthat feeds on them.

Picture 4.1
The influence of the human waste

Photochemical ozone formation
Ozone is not usually emitted directly into the air, but at ground-level is created by a chemical reaction between oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence of sunlight. Depending on its location in the atmosphere can be good or bad. In the earth's lower atmosphere, ground-level ozone is considered 'bad.'
Motor vehicle exhaust and industrial emissions, gasoline vapors, and chemical solvents as well as natural sources emit NOx and VOC that help form ozone. Look at pie chart 5.1 and diagram 5.2.
Numerous scientific health studies have linked ground-level ozone exposure to a variety of harmful problems, including: airway irritation, coughing, and pain when taking a deep breath; breathing difficulties during exercise or outdoor activities; inflammation; aggravation of asthma and increased susceptibility to respiratory illnesses like pneumonia and bronchitis.
Moreover, ground-level ozone can have detrimental effects on plants and ecosystems like interfering with the ability of sensitive plants to produce and store food, making them more susceptible to certain diseases, insects and other pollutants; damaging the leaves of trees and other plants, negatively impacting the appearance of urban vegetation; and reducing forest growth and crop yields, potentially impacting species diversity in ecosystems.

Diagram 5.2
Also indicates the main source of ground-level ozone; and the good and bad zones

Chart 5.1
Thepie chart shows the influence depending on the source



To sum up, it is important, when you carry out a lyfe-cycle assessments, to look after the environmental impact and the possible global warming effects, which will increased if we are not careful of the whole production process.
The ecological consequences are extreme, and the result may be the replacement of an original ecosystem by an entirely different one; because human accelerate the progression as compared to a natural landscape evolution. In such accelerated circumstances, organisms may not have the time needed to migrate or adapt to the rapidly altered new environment.

Bibliography

* Handbook on Environmental Assessment of Products
Kirsten Pommer and Pernille Bech, Henrik Wenzel, Nina Caspersen and Stig Irving Olsen

* https://www.myclimatechange.net

* https://www.grida.no

* https://environment.nationalgeographic.com/environment/global-warming/ozone-depletion-overview/

* https://en.wikipedia.org/wiki/File:Sources_of_stratospheric_chlorine.png

* https://www.policyalmanac.org/environment/archive/acid_rain.shtml

* https://www.epa.gov/acidrain/what/

* https://www.udel.edu/chem/C465/senior/fall97/acid_rain/pie.gif

* https://www.eoearth.org/article/Eutrophication

* https://www.water-pollution.org.uk/eutrophication.html

* https://www.cd3wd.com/cd3wd_40/ap/Eutrophication.html

* https://www.deq.state.la.us/portal/PROGRAMS/OzoneActionProgram/OzoneFactsandExperiments/TypesofOzone.aspx

* https://www.epa.gov/glo/