What are the environmental impacts and impact assessment?

There is no product with zero environmental impact. Even so-called "green," "ecological," "good for the environment" products have negative effects on the environment, mainly due to their manufacturing process. Even when special attention is paid to it to lessen its environmental consequences, no process is completely neutral.

Indeed, to manufacture any product, we need raw materials and energy. All products must be packed and transferred. Finally, even if it is recycled many times, any product or packaging will one day become waste. Therefore, the challenge is to identify which product has less impact than another for the same use.

So what are the environmental impacts?

1. The concept of environmental impact

The concept of environmental impact refers to all the qualitative, quantitative, and functional modifications of the environment (negative or positive) generated by a project, a process, one or more organisms, and one or more products, from its design to its "end of life."

The concept of environmental impact refers to the consequences of a natural phenomenon (such as a tsunami or earthquake), although this meaning is rather rare. Usually, the concept is to refer to the collateral effects that some economic exploitation involves nature. In other words, a company can create jobs and be very profitable from an economic point of view, but can also destroy the environment of the areas bordering its factory. However, the environmental impact can have consequences for the population's health, the quality of the air, and the beauty of the landscape.

2. Definition of environmental impact study

An environmental impact study (EIA) is both an administrative procedure and a technical study before carrying out a major project. Appeared in the 20^th century, these studies aim to estimate the consequences of human action, particularly on the environment and human health, and try to limit the drawbacks.

The environmental impact study is the responsibility of the project owner. It explores its negative consequences and describes the measures envisaged to eliminate, limit, or compensate for them:

• Nuisances (sound, visual, aesthetic ...),
• Water use and protection of groundwater,
• Pollution (purification and evacuation of wastewater, treatment of gaseous fumes, elimination of waste and operational residues),
• Transport of incoming materials and manufactured products,
• Dangers in the event of an incident,
• Damage to the ecosystem (flora, fauna, biodiversity),

3. Environmental impact assessment

Environmental impact assessment refers to implementing methods and procedures to estimate the environmental consequences of a policy, program, plan, project, or achievement; by extension, the report accounts for it.

The environmental assessment is an opinion issued on the environmental impact study to check its quality and assess how the negative environmental impacts are effectively canceled, reduced, or compensated.

Therefore, environmental impact assessment is the preliminary, global, and critical analysis of the environmental problems, effects, and results, both positive and negative, of the activities of an establishment, project, or policy. Different methodologies exist. Environmental assessment is usually very much linked to the general policy of the country and its regulations.

The assessment of an environmental impact is quantified through the measurement of flow indicators and potential impact indicators.

For air, we retain five indicators:

• Contribution to the greenhouse effect;
• Acidification of the air;
• Formation of ground-level ozone;
• Depletion of the ozone layer;
• Particles and respiratory effects of inorganic substances.

For water, we retain four:

• Eutrophication of freshwater;
• Aquatic ecotoxicity;
• Eutrophication of marine waters;
• Water consumption (flow indicator).

For soil resources and human health, there are the following four indicators:

• Primary energy consumption (flow indicator);
• Depletion of non-renewable resources;
• Human toxicity;
• Land use.

4. Environmental impact assessment method

Impact analysis methods make it possible to link the data from a life cycle analysis inventory (e.g., substances or processes) to the environmental damage that they are likely to cause or to which they are affected.

The first methods were based on critical volumes and made it possible to classify emissions according to the affected environment (water, air, and soil) by calculating, for each pollutant, the equivalent volume polluted up to a limit value. Certain inconsistencies in these methods (they do not take into account the persistence of emissions and the fate of pollutants) have led to their abandonment.

Depending on the positioning on the chain linking the causes to the effect and according to the objectives sought and the scale is taken into account, the impact calculation methods grouped into two categories, respectively:

Mid-point methods

Problem-oriented, they quantify the overall effects of substances emitted or consumed. The impact appears in the middle of the causal chain. The inventory results with similar effects arranged together in impact categories called intermediate categories, to which an intermediate indicator ("mid-point indicator") is associated, which makes it possible to compare the flows of substances contributing to the category in question.

End-point (or damage) methods

The impact will be at the end of the causal chain; these methods allow to estimate the potential damages that could by allocating several intermediate categories to one or more damage categories. Damage indicators then represent these.

5. Environmental impact; What are the negative effects on the environment?

Global warming or disruption due to increased concentrations of greenhouse gases. During the 20^th century, general warming of the planet of + 0.5 ° C was observed. If this phenomenon persists and grows, global warming could cause glaciers to melt completely and mean sea level rise.

The ozone layer hole: the destruction of stratospheric ozone is due to the action of certain chemical compounds based on chlorine and bromine, such as chlorofluorocarbons (CFCs) or methyl bromides (CH3Br ), resulting from human activities. They took steps to reduce emissions of such substances into the air, such as the total shutdown of CFC production since 1994 (Montreal Protocol).

Ecosystem alterations; Acutely or chronically, atmospheric pollutants have heavy impacts on crops and ecosystems.

Occasionally, during strong ozone pollution episodes, necrosis or spots appear on tree leaves. Over a period of prolonged exposure to ozone, a weakening of organisms, and a strong slowing down of growth observed, this ultimately affects agricultural crops.