A landfill is a site for the disposal of waste materials by burying or covering them with soil. Garbage dumps are commonly used for this purpose. Landfills are common in urban areas to accommodate the dumping of waste materials from municipal solid waste, industrial and commercial operations.
The solid garbage in landfills results in air pollution by the production of methane and carbon dioxide gases during their degradation. These are greenhouse gases that cause global warming. In addition, solid garbage also releases chemicals into the atmosphere leading to further pollution.
Let us see in detail what happens in landfills when solid garbage gets decomposed then emitted into the atmosphere.
How solid garbage in landfills result in air pollution
Even though the garbage sent to landfills is mostly solid, it can lead to air pollution. Here are various ways they pollute our atmosphere;
Production of greenhouse gases
Many greenhouse gases are produced by the decaying of organic solid materials dumped into landfills. While they produce more than ten gases 90-98% of them account for methane and carbon dioxide.
The methane gas produced due to the decomposition of solid garbage releases into the atmosphere and this results in an increased concentration of methane in the atmosphere. Methane is a greenhouse gas that is more than 20,000 times more effective than carbon dioxide in trapping heat within the atmosphere.
The release of methane into the atmosphere leads to global warming. The current rate of methane emission in the world is 15 times higher than that of carbon dioxide. Methane emissions have accelerated in recent years due to the increased consumption of fossil fuels for energy.
The other gases produced in landfills include nitrogen, oxygen, ammonia, sulfides, hydrogen etc. Their volume is negligible compared to that of carbon dioxide and methane produced.
Pollution caused by fires
Fires in landfills are nothing new. The United States sees an average of 8300 fires a year. These fires emit huge amounts of dust and dangerous gases into the atmosphere. These fires significantly reduce air quality and cause health hazards to those living nearby. The above estimate is only for the USA. Fires like this happen all around the world, and the cumulative effect they have on our atmosphere is huge.
Gases from chemicals
It is not just biodegradable solids that are dumped into landfills. Many solid wastes which have chemicals in them end up in these places. When they degrade, they release harmful chemicals into the atmosphere polluting the air. These chemicals in the atmosphere sometimes lead to acid rains which harm the vegetation as well as the lives of people.
Release of harmful chemicals due to flooding
When storms and floods hit the landfills, there is a possibility that the solid wastes may get washed away. If this happens, it can release dangerous chemicals into the water bodies and further into the atmosphere. Sometimes such floods can lead to a greater disaster, as happened during Hurricane Katrina in New Orleans when toxic chemicals from toxic dump sites were released into the nearby waterways and spread all over the city, reducing air quality.
What does a landfill consist of?
Most of the solid wastes in landfills consist of;
The organic wastes ending up in landfills mostly come from households. It mostly consists of foods we wasted. Sometimes, this waste is used as landfill cover.
The plastic wastes in landfills come from households and industries. They are usually bags, bottles, packaging materials, or containers used in industries and farms. It can also be other manufactured products such as furniture or electronic parts. Larger amounts of plastic waste are recycled into new products, rather than ending up as landfills.
The glass wastes in landfills are mainly broken glass from households. Some of it is recycled, such as making new bottles or used as fillers for road construction. It can also be used to manufacture low-grade sands.
The metal wastes in landfills are from industries or products such as automobiles, refrigerators, washing machines, and some from households as well. Metal waste can be recycled into new products or melted down to produce new metal alloys. In this way, it is possible to reduce the amount of metals in landfills.
The wood wastes in landfills come mostly from the construction industry and households. Recently there has been an increase in the use of wood shavings in making paper pulp. This reduces the number of wastes going to landfills.
Rubber wastes in landfills mostly come from the tyres of vehicles. In most cases, tyres are recycled into new products such as carpets and running tracks for sports arenas. This reduces the amount of rubber ending up in landfills.
Among the above, only organic wastes release methane into the atmosphere. However, all other wastes emit toxic gases when landfill fires happen.
How to reduce air pollution due to solids in landfills
The garbage dumped in landfills comes from the waste generated by people at home and at work. So, the reduction of air pollution from landfills should start from our homes and workplaces. This can be achieved by stressing the importance of recycling and composting.
Recycling is a process that involves collecting and processing used materials into new products. This process can be done at home, work and schools. These actions can help lessen the amount of waste dumped in landfills. In addition, recycling helps to reduce the need of new raw materials and thus helps to further save the environment.
As most of the methane generating solid wastes in landfills is food wastes, composting food scraps can considerably reduce air pollution. Composting is a process called aerobic decomposition, which makes use of microorganisms to break down organic materials and release carbon dioxide (CO2) and water as a product. At home, composting can be done in the backyard or inside the kitchen with a worm bin or indoor composting.