CHAPTER 3: LIFE ON THE LINE


of stakeholders and the involvement of each and every one of us is key.


Orange may be the next black - is nitrogen the next carbon?


UN Environment is partnering with the Organisation for Economic Co-operation and Development (OECD) and various international organizations to combat the threat of nitrogen pollution. Nitrogen, along with phosphorus, has been identified as having exceeded their planetary boundaries – the safe operating space for humanity (Rockstrom, 2015). International society came together to combat carbon emissions – can we now do the same for nitrogen?


3.3 Air pollution, the inescapable threat One of the things that is absolutely necessary for life


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is breathable, clean air. It is from the atmosphere that all organisms, including humans, take the gases that they need to survive. Keeping air clean requires all components of ecosystems. For example, plants filter the air and dissipate pollutants, while being the source of oxygen on which all animals, including humans, depend.


But some processes also contribute harmful substances in the atmosphere (Figure 20). Gaseous air pollutants include nitrous and sulphur oxides


(NOx; SOx), which contribute to smog, haze and acid rain. Ozone (O3) found in the stratosphere is essential to life because it keeps ultraviolet light from reaching


the surface of the Earth. However, excess ozone at ground level can have harmful effects on human health, crops and the climate.


Gaseous air pollutants


NOx - Nitrogen oxides O3 - Ozone SOx - Sulphur oxides TMs - Tetramethylsilane


NOx SOx


As - Arsenic Cd - Cadmium Pb - Lead PAHs - Polycyclic aromatic hydrocarbons BC - Black carbon


O3


acid rain smog haze


Particulate matter


(PM10,PM2.5) TMs


As Cd Pb


BC PAHs


Figure 20: Gaseous pollutants and their harmful effects on human beings


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