Basic knowledge of climate and the environment
Climate and the environment are often discussed in the same context, but they do not describe the same thing. When we talk about emissions, greenhouse gases and air pollution, it is important to know the difference – both to understand the global climate impact and the local environmental impacts around us.
Climate and the environment are not the same
Climate concerns the global consequences of an excessive concentration of greenhouse gases in the atmosphere. When the concentration becomes too high, it contributes to the greenhouse effect and can lead to more extreme weather conditions, among other things.
The environment is more concerned with local impacts. Air pollution, for example, can reduce air quality in the local area and affect breathing, skin, lungs and respiration. Environmental impacts can also affect aquatic environments and biodiversity when pollutants are released into the surroundings.
Greenhouse gases and CO2 equivalents
Greenhouse gases are often abbreviated internationally as GHG. The best-known examples are carbon dioxide, methane and nitrous oxide, all of which affect the climate, but in different ways.
Carbon dioxide, CO2, consists of one carbon atom and two oxygen atoms. Methane, CH4, consists of one carbon atom and four hydrogen atoms. Laughing gas, N2O, is known internationally as nitrous oxide and consists of two nitrogen atoms and one oxygen atom.
When emissions are calculated collectively, the term CO2 equivalent, abbreviated as CO2-eq, is often used. This makes it possible to compare different greenhouse gases in a single calculation. In more general descriptions, CO2 is often used as a simplified collective term, even though several different greenhouse gases may actually be involved.
| Greenhouse gas | Chemical formula | CO2-eq (factor) | Breakdown time (atmospheric lifetime) |
| Carbon dioxide | CO₂ | 1 | Approx. 50-200 years |
| Methane | CH4 | Approx. 25-28 | Approx. 12 years |
| Nitrous oxide | N2O | Approx. 298 | Approx. 114 years |
Understanding the differences between greenhouse gases
Greenhouse gases differ in both potency and atmospheric lifetime. CO2 is used as the reference point, with a CO2-eq factor of 1. Methane has a stronger climate effect per unit emitted, but typically has a shorter atmospheric lifetime. Nitrous oxide has an even higher CO2-eq factor and remains in the atmosphere for a long time.
- Carbon dioxide, CO2: CO2-eq factor of 1 and a lifetime of approximately 50-200 years
- Methane, CH4: CO2-eq factor of approximately 25-28 and a lifetime of approximately 12 years
- Nitrous oxide, N2O: CO2-eq factor of approximately 298 and a lifetime of approximately 114 years
- CO2 remains the most important greenhouse gas to monitor because it is emitted in large quantities and can remain in the atmosphere for a long time
- CH4 and N2O have a stronger impact per unit, but account for a smaller proportion of human-made emissions than CO2
Air pollution is about local impact
Air pollution occurs when human activities release substances into the air that are foreign to the environment. Concentrations are often higher in larger cities than in rural areas, partly due to traffic, combustion and industrial activities.
Some of the most relevant air pollutants to be aware of are NOx, SO2 and particulate matter. NOx is a collective term for nitrogen oxides such as NO and NO2. NO can form at high temperatures, for example in a combustion engine, and can be converted into NO2 in the air. Nitrogen can affect oxygen saturation, contribute to biodiversity loss and promote algal growth in bodies of water.
SO2 is sulphur dioxide and is one of the common compounds of sulphur and oxygen. It belongs to the broader group of sulphur oxides, SOx.
Particulate matter consists of small particles in the air, classified by size. PM2.5 refers to fine particles with a diameter of less than 2.5 micrometres. PM10 is used for coarser particles, while ultrafine particles are even smaller. Fine and ultrafine particles are particularly important to monitor because they can penetrate deep into the respiratory tract.
Environmental impact
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