Farming is an essential part of human civilization, providing the food and resources necessary for survival. Agricultural air pollution comes from both farm equipment and farming itself, which includes the soil, plants, animals and fertilizers. A study published in Geophysical Research Letters found that emissions from farms outweigh all other human sources of fine-particulate air pollution in much of the United States, Europe, Russia and China. The harmful gases from agricultural practices can have a significant impact on air quality, which inevitably affects mankind. Research shows that animal agriculture alone is responsible for 80% of deaths from pollution related to food production. 

Fig 1 below shows the volume of greenhouse gas emissions from both food and non-food sources. Evidently, food contributes almost one-third of global emissions, with a large proportion stemming from livestock rearing and crop production. 

Fig 1: Global greenhouse gas emissions from food production (Source: Poore and Nemecek, 2018)

Fertilizers and Pesticides

One of the primary ways that farming contributes to poorer air quality is via the excessive utilization of fertilizers and pesticides. These chemicals are essential for the growth of crops and might even help to increase total yield or enhance land productivity, but the surge in its adoption worldwide led to the release of toxic pollutants into the atmosphere. For instance, the nitrogen compound in fertilizers can contribute to the formation of ground-level ozone, a potent air pollutant. Similarly, pesticides release volatile organic compounds (VOCs) into the air, which leads to smog and lowered air quality. They remain in the air for prolonged periods, contaminate water and soils, as well as bring acid rain. 

 

Burning of Crops

Another source of air pollution is derived from crop burning. Farmers often burn crops as a means to remove residual plant matter, but such destructive practices release large amounts of particulate matter and other pollutants into the environment. Farmers also engage in crop burning to clear land or as a source of biofuel. In Indonesia, it was estimated that 45 million tonnes of crop residues are open burned annually. Open burning (Fig 2) accounts for more than a third of all black carbon emissions and represents one of the largest sources of air pollution-related illnesses. Therefore, these practices seriously pollute the air and can increase global warming potential by up to 14%. 

Fig 2: The practice of open burning in farms (Source: Urban Update, 2019)

Livestock

Last but not least, methane emissions from the rearing of livestock is also a major contributor to air pollution from farming. According to the Food and Agriculture Organization, the 3.5 billion ruminants raised as livestock worldwide generate approximately 6% of anthropogenic greenhouse gas emissions, with each cow emitting up to 100kg of methane per year. Livestock methane emissions are projected to rise 30% by 2050 following the increase in the global population and our appetite for meat and dairy products. Cows and cattle generate methane in two ways (Fig 3) – via digestion and through excretion. To put it simply, a small amount of methane is released into the air every time the animal burps or farts. Furthermore, the decomposition of their manure generates a substantial amount of methane as well. 

Fig 3: Emissions from various livestock (Source: Gustin, 2019)

Farming will continue to contribute largely towards air pollution and climate change, given the use of environmentally destructive practices. These effects will trickle down to impact future generations, flora and fauna, as well as other living organisms. However, there are measures that can be taken to mitigate the problem, such as reducing the use of harmful pesticides and fertilizers, and adopting agroecological farming practices that are nature-friendly. 

 

Bibliography

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