#EMISSIONS MUST FALL

Pollutants and Air Quality

 Air pollutants are responsible for a number of adverse environmental effects, such as photochemical smog, acid rain, death of forests, or reduced atmospheric visibility. Emissions of greenhouse gases from combustion of fossil fuels are associated with the global warming of Earth’s climate. Certain air pollutants, including black carbon, not only contribute to global warming, but are also suspected of having immediate effect on regional climates.

Air pollutants are substances that adversely affect the environment by interfering with climate, the physiology of plants, animal species, entire ecosystems, as well as with human property in the form of agricultural crops or man-made structures. Climate tops the list to reflect the fact that global climate change has been recognized as one of the most serious environmental challenges to be faced by humanity in the 21st century. In this context certain climate forcing agents, the most important one being carbon dioxide which otherwise cause no harm to living organisms, should be added to the list of “classic” pollutants, along with such compounds as oxides of nitrogen or sulfur. On the other hand, climate research has linked certain compounds long recognized as air pollutants (for instance black carbon) to the warming of climate, thus providing one more reason for their control.

Air pollutants originate from natural or anthropogenic (man-made) sources, or both. Examples of natural sources of pollution include volcanic eruptions or wind erosion. Emissions from internal combustion engines are an exemplary source of anthropogenic pollution. Some sources of pollution, such as forest fires, can be related to both natural phenomena and human activities.

The table below shows the air pollutants, their sources and effects on all living things combined. It shows also that combined effort is needed to rise above these effects for healthy living.

Air Pollutants, their Sources, and effects
Pollutant	Natural Source	Anthropogenic Source	Environmental Effect
Nitrogen oxides (NO + NO2)	Lightnings, soil bacteria	High temperature fuel combustion—motor vehicles, industrial, and utility	Primary pollutants that produce photochemical smog, acid rain, and nitrate particulates. Destruction of stratospheric ozone. Human health impact.
Particulates	Forest fires, wind erosion, volcanic eruption	Combustion of biofuels such as wood, and fossil fuels such as coal or diesel	Reduced atmospheric visibility. Human health impact. Black carbon particulates contribute to global warming.
Sulfur dioxide	Volcanic eruptions and decay	Coal combustion, ore smelters, petroleum refineries, diesel engines burning high-sulfur fuels	Acid rain. Human health impact.
Ozone	Lightning, photochemical reactions in the troposphere	Secondary pollutant produced in photochemical smog	Damage to plants, crops, and man-made products. Human health impact.
Carbon monoxide	Unnoticeable	Rich & stoichiometric combustion, mainly from motor vehicles	Human health impact
Carbon dioxide	Animal respiration, decay, release from oceans	Fossil fuel and wood combustion	Most common greenhouse gas
Non-methane hydrocarbons (VOC)	Biological processes	Incomplete combustion, solvent utilization	Primary pollutants that produce photochemical smog
Methane	Anaerobic decay, cud-chewing animals, oil wells	Natural gas leak and combustion	Greenhouse gas
Chlorofluorocarbons (CFC)	None	Solvents, aerosol propellants, refrigerants	Destruction of stratospheric ozone

According to the German Environment Agency, German CO2 emissions per capita alone amounted to around 11 tonnes in 2016. This is 2.5 tonnes more than the European average and more than double the global average of around 4.4 tonnes of CO2. Per capita CO2 emissions are much lower in many developing countries. If global warming is to be limited to well below 2°C, the international community must strive to achieve the goal it set itself at the Paris declaration in 2015. Since current and past emissions are so unevenly distributed, countries must make different substantial efforts to stop these emissions.

Ambitious steps must be taken and it is perhaps feasible if we all contribute to it. What we need is enormous political steps for example towards energy production from 100 percent renewable energy sources. Each and every one of us can do a lot, because many of our activities can be made more climate-friendly. Whether it's an organization, a private individual or whatever, everyone should consider how and where greenhouse gas emissions can be avoided and reduced. Our collective failure to act early and hard on climate change means we now must deliver deep cuts to emissions.

#LET'S GET TO WORK