Burning Agricultural Waste
In many countries, burning agricultural waste, such as stalks, grasses, leaves and husks, continues to be
the easiest and least expensive way to reduce or eliminate the volume of combustible materials produced
by agricultural activities. Open-air burning is used to eliminate waste from the previous harvest in the
quickest manner, and to clear fields to prepare them for planting. It is also used to release nutrients for the
following growing season and to eliminate mosquitoes and other pests in crop-growing fields. Sugar cane
fields are burned prior to harvesting to remove excess leaves and thus facilitate the harvesting and
transporting of products to sugar refineries. It is also believed that burning the sugar cane fields reduces
the risk of insect bites and cuts for workers.
It is estimated that burning biomass, such as wood, leaves, trees and grasses—including agricultural
waste—produces 40% of carbon dioxide (CO2), 32% of carbon monoxide (CO), 20% of particulate matter
(PM), and 50% of polycyclic aromatic hydrocarbons (PAHs) released into the environment around the
globe.2
Although agricultural waste burning is not an environmentally acceptable form of agricultural
management, it is a frequent practice and is worrisome from a public health viewpoint for a number of
reasons:3
• Smoke from agricultural burning is released at or near ground level in areas that are generally
populated, producing direct, intense exposure to pollutants for the nearby populations.
• This type of burning is generally carried out in stages, during specific times of the year, and may
lead to very high concentrations of pollutants.
• Burning agricultural waste creates non-specific sources of pollutants for the atmosphere and takes
place over very large areas. It is therefore difficult to measure and to regulate the resulting
emissions.
• Combustibles and combustion conditions vary, and pesticides may be present.
• This type of burning contributes to climate change, since among the compounds released are
greenhouse gases and short-lived climate-forcing pollutants like black carbon.
• Visibility in nearby areas and highways is affected.
• In addition, these incomplete combustion processes produce dioxins, which are highly toxic,
carcinogenic pollutants.