Fertilizers: Air Polluters And Their Unseen Impact

Fertilizers are a significant contributor to air pollution. While air pollution from fertilizers is usually associated with energy production and vehicle emissions, the use of fertilizers on crop fields is a major source of air pollution. Fertilizers are a source of nitrogen oxide (NOx) pollution, which includes nitrogen oxide (NO) and nitrogen dioxide (NO2). The use of nitrogen-based fertilizers, in particular, has been found to cause air pollution. Ammonia emissions from fertilizers are also a concern, as they can react with other pollutants to form fine particulate matter, which is harmful to human health.

Nitrogen-based fertilizers

Synthetic nitrogen fertilizers, which are widely used in conventional agriculture, can lead to increased air pollution when they are not fully utilized by plants. This excess nitrogen can escape from farm fields and negatively impact air quality. It contributes to the formation of ground-level ozone, higher amounts of greenhouse gases, and the depletion of the protective ozone layer. Additionally, it has been linked to acid rain, polluted drinking water, and oxygen depletion in water bodies, which harms aquatic ecosystems.

The impact of nitrogen fertilizers on air pollution varies depending on the crop. Studies have found that rice and corn crops tend to exacerbate air pollution, while the effects on wheat are less clear. Furthermore, nitrogen fertilizers contribute to increased levels of PM2.5 and SO2 in the atmosphere, which are harmful pollutants.

To address these issues, advocates urge farmers to reduce their reliance on soluble, synthetic nitrogen fertilizers and transition to insoluble soil amendments that support soil biology and provide nutrients to plants. Organic nitrogen fertilizers, for example, require biological life in the soil to break down the fertilizer into a form that plants can use, reducing the potential for pollution. Precision farming techniques can also enhance nitrogen uptake by plants, reducing nitrogen losses into the air.

Ammonia emissions

Ammonia (NH3) emissions are a significant contributor to air pollution, with agriculture being responsible for 92% of volatile ammonia emissions. This includes ammonia-based fertilizers and animal manure. The use of nitrogen fertilizers accounts for 17% of ammonia emissions, while livestock and manure management and application contribute 64%. Atmospheric ammonia released from agricultural activities has severe health, environmental, and economic impacts.

In addition to health impacts, ammonia emissions from agriculture can result in excessive levels of nutrients in soil, rivers, and lakes. This can have detrimental effects on aquatic ecosystems and damage forests, crops, and other vegetation. The European Environment Agency (EEA) has reported that emissions of ammonia from the agricultural sector in the EU have been rising, making it challenging for member states to meet air pollution limits.

To address the issue of ammonia emissions, effective reduction strategies are necessary. Precision farming, for example, can enhance nitrogen uptake by plants, reducing ammonia losses to the air. Adopting insoluble soil amendments that support soil biology and provide nutrients to plants is another recommended approach. Additionally, the use of organic fertilizers and the implementation of best cultural practices can help mitigate ammonia emissions and reduce pollution problems.

While regulations for agricultural ammonia emissions exist, they have been largely ineffective worldwide. The European fertilizer industry is actively working on developing new tools to support farmers in making fertilization decisions and improving nutrient use to reduce ammonia emissions. International trade also plays a role in ammonia emissions, with approximately 25% of global agricultural ammonia emissions in 2012 attributed to exported goods.

Particulate matter

Fertilizers are a significant contributor to air pollution, particularly in the form of particulate matter. Particulate matter refers to tiny solid particles or aerosols suspended in the air, which can have detrimental effects on human health and the environment. These particles are often the result of a combination of agricultural practices, traffic, and industrial activities.

Agricultural air pollution is primarily associated with ammonia (NH3) emissions from heavily fertilized fields and livestock waste. Ammonia, a colourless gas with a characteristic pungent smell, is released into the atmosphere from fertilizers and animal manure used in agriculture. It then combines with other pollutants, such as nitrogen oxides (NOx) and sulfates from vehicle emissions, power plants, and industrial processes, to form particulate matter. This process is known as the secondary formation of particles, where the interaction of ammonia with other pollutants leads to the creation of fine solid particles.

Nitrogen compounds, particularly nitrogen oxides (NOx), play a significant role in the formation of particulate matter. The overuse of synthetic or inorganic fertilizers that contain nitrogen can result in excess nitrogen being released into the atmosphere. This excess nitrogen returns to the environment as nitrogen oxides, which have a significantly more substantial greenhouse effect than carbon dioxide. Nitrogen oxides contribute to air pollution and have detrimental effects on human health, impacting the respiratory, circulatory, and immune systems. They are also associated with the development of pathologies in organs such as the liver and spleen.

The application of fertilizers on crop fields has been identified as a significant source of NOx emissions, which contribute to air pollution, acid rain, and respiratory illnesses. While nitrogen is essential for the growth of agricultural crops, its excessive use through fertilizers can have negative consequences. Improper fertilizer management, such as applying excessive amounts or using them in areas where they are not fully utilized by plants, can lead to nitrogen compounds being released into the air. This imprudent use of fertilizers on gardens, lawns, and landscapes also contributes to non-point nitrogen pollution.

Nitrogen management

Nitrogen fertilizers are a significant contributor to air pollution. While nitrogen oxide (NOx) pollution is usually associated with energy production and vehicle emissions, fertilizer use on crop fields is a major source of pollution in the US and worldwide. Chemical-intensive, synthetic nitrogen fertilizers are applied in a form that is readily available to plants. However, when nitrogen is not immediately taken up by plants, it can escape into the atmosphere, causing pollution problems.

The impact of nitrogen fertilizer application on air pollution has been studied in China, and it was found that nitrogen management can effectively reduce air pollution. The study found that a 1 g nitrogen increase in fertilizer correlates with a rise of 0.55 μg/m³ in PM2.5 concentrations. Additionally, rice and corn crops were found to exacerbate air pollution, while the impact of nitrogen fertilizer on wheat remains unclear.

In California, researchers have found that the contribution of croplands to NOx air pollution may be significantly higher than previously thought. The California Air Resources Board (CARB) indicates that only 3.8% of NOx air pollution comes from croplands, but researchers determined that the actual contribution may be between 20% and 51%. This discrepancy may be due to the methodology used to record cropland emissions, as CARB only measures emissions from farms within 125 miles of Sacramento, excluding areas with more intensive agricultural production.

To reduce nitrogen pollution, farmers can adopt insoluble soil amendments that support soil biology and provide plants with nutrients. Organic nitrogen fertilizers, for example, require biological life in the soil to break down the fertilizer into a form that plants can use, reducing the risk of pollution. Additionally, farmers can focus on cultural practices and conduct soil tests to determine the need for fertilizer. By choosing organic certified fertilizers and supporting organic farming practices, the risk of nitrogen pollution can be mitigated.

Industrial emissions

The use of synthetic fertilizers on farms also contributes to air pollution. Nitrogen-rich fertilizers, when combined with industrial emissions, form solid particles that are a significant source of disease and death. These fine particles can penetrate deep into the lungs, causing heart or pulmonary issues. While nitrogen oxide (NOx) pollution is typically associated with energy production and vehicle emissions, fertilizer use on crop fields contributes significantly to this issue.

The production of artificial fertilizers has skyrocketed, with about a third of them being nitrogen-based. As a result, the amount of aerosols created has increased, and these aerosols contribute to air pollution. The impact of nitrogen fertilizer application on air pollution varies across crops, with rice and corn exacerbating pollution, while the effect on wheat remains unclear.

To mitigate the environmental impact of the fertilizer industry, continuous monitoring and regulation of nitrogen oxide levels in the air are necessary. Accurate measurements of agricultural emissions must be obtained to address this issue effectively. The synthetic fertilizer industry can also install sensors to monitor the emissions of polluting gases, allowing for early detection and activation of warning systems in case of anomalies.

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