Question

Why is burning plastic #2, #3 and #4 at high temperature, in a wood stove, on a bed of hot wood coals a problem? These three plastics only contain carbon and hydrogen so they should burn cleaner than wood?

Answer 1

Burning plastic #2 (HDPE - High-Density Polyethylene), #3 (PVC - Polyvinyl Chloride), and #4 (LDPE - Low-Density Polyethylene) in a wood stove, or any other open flame, is a significant problem due to several reasons:

1. Toxic Fumes: While these plastics primarily contain carbon and hydrogen, burning them at high temperatures in an open flame releases toxic fumes and pollutants. PVC, in particular, contains chlorine atoms, and when burned, it releases highly toxic and corrosive hydrogen chloride gas. Inhaling these fumes can be harmful to human health and the environment.

2. Dioxin Emissions: Burning PVC, in particular, can result in the formation of dioxins and furans, which are extremely toxic and persistent environmental pollutants. Dioxins are known to be carcinogenic and can have severe impacts on the environment, even in trace amounts.

3. Incomplete Combustion: Achieving complete combustion of plastics in an open flame is challenging. The high-density of plastics, as well as the difficulty in mixing them thoroughly with oxygen in an open setting, often leads to incomplete combustion. This means that not all the carbon and hydrogen in the plastic fully convert to carbon dioxide and water vapor, resulting in the release of harmful by-products.

4. Ash and Residue: Burning plastics in a wood stove can leave behind a sticky residue and ash. This can coat the stove and chimney, leading to reduced efficiency and potential maintenance issues.

5. Safety Concerns: Burning plastics in a wood stove can lead to an increased risk of chimney fires due to the release of flammable materials and the potential buildup of creosote in the chimney.

6. Air Quality: The emissions from burning plastics contribute to air pollution and can worsen local air quality. This is especially concerning in areas with poor ventilation, as the toxic fumes can accumulate indoors.

In summary, while burning plastic #2, #3, and #4 might seem like a way to dispose of waste, it poses significant risks to human health and the environment. The high temperatures and conditions required for proper and safe combustion of plastics are typically found in specialized waste-to-energy facilities with stringent pollution control measures.

If you need to dispose of plastics, it's essential to follow proper recycling or waste management practices designated by your local authorities. Burning plastics or any other materials in a wood stove is not an acceptable or safe method of waste disposal.