Kerosene Lamps Major Source of Black Carbon

According to a new finding, kerosene lamps are producing black carbon at levels previously overlooked in greenhouse gas estimates. 

Kerosene lamps are a source of light for people living in rural areas of Asia and Africa. Though it is one of the least expensive liquid fuels, it is extremely inefficient, unsafe and has extensive health and environmental drawbacks.

According to a new finding, kerosene lamps are producing black carbon at levels previously ignored in greenhouse gas estimates.

This study was conducted by researchers at the University of California, Berkeley and the University of Illinois.

They conducted field and lab tests and noticed that 7 to 9 percent of the kerosene in wick lamps is converted to black carbon when burned. This kerosene is mostly used for light in 250-300 million households without electricity. In comparison, only half of 1 percent of the emissions from burning wood is converted to black carbon.

The study results show a 20 fold increase in estimates of black carbon emissions from kerosene-fueled lighting. The previous estimates come from established databases used by the Intergovernmental Panel on Climate Change and other sources.

The study says, one kilogram of black carbon, a byproduct of incomplete combustion and an important greenhouse gas, produces as much warming in a month as 700 kilograms of carbon dioxide does over 100 years.

"The orange glow in flames comes from black carbon, so the brighter the glow, the more black carbon is being made," said study principal investigator Tami Bond, associate professor of civil and environmental engineering at the University of Illinois at Urbana-Champaign. "If it's not burned away, it goes into the atmosphere."

Officials from around the world are seeking effective policies and guidelines for cutting greenhouse gas emissions.

"There are no magic bullets that will solve all of our greenhouse gas problems, but replacing kerosene lamps is low-hanging fruit, and we don't have many examples of that in the climate world," said study co-author Kirk Smith, professor at UC Berkeley's School of Public Health and director of the Global Health and Environment Program. "There are many inexpensive, cleaner alternatives to kerosene lamps that are available now, and few if any barriers to switching to them."

Smith focuses on the lanterns with light emitting diodes that can be powered by solar cells or even advanced cook stoves that generate electricity from the heat produced. He says these are available in developing countries.

In order to measure the emissions, the researchers used kerosene lamps purchased in Uganda and Peru. They conducted field experiments with these lamps. The tests were repeated in the lab using wicks of varying heights and materials and kerosene purchased in the United States as well as in Uganda.

The researchers suggest that converting to cleaner light sources would not only benefit the planet, it would help improve people's health. 

"Getting rid of kerosene lamps may seem like a small, inconsequential step to take, but when considering the collective impact of hundreds of millions of households, it's a simple move that affects the planet," says study lead author Nicholas Lam, a UC Berkeley graduate student in environmental health sciences.

The findings were published online this month in the journal Environmental Science & Technology.