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"Black carbon", one of the main threats to cities


It is a volatile compound, whose small particles of 0.1 to 0.5 microns penetrate the respiratory tract and affect its functions, said Xochitl Cruz Núñez, a researcher at the Center for Atmospheric Sciences (CCA) of the UNAM.
"Among the particles emitted by fossil fuels and biofuels is black carbon, a conglomerate of particles in solid, liquid and gaseous states, which have a large amount of hydrocarbons and, being volatile, are released and easily pass into the phase soda, "said the teacher in chemical sciences.

In a publicity talk on the subject, offered in the Julián Adem Chahín auditorium of the CCA, Cruz Núñez highlighted that this compound has a short life in the atmosphere, which goes from hours to days and, therefore, mitigating its emissions immediately supports reducing the greenhouse effect.

Although black carbon emissions are low compared to those of other pollutants such as carbon dioxide and methane, its impact on climate change is important, since one of its characteristics is that it absorbs solar radiation that it emits as infrared radiation, which which contributes to the greenhouse effect.

"In the atmosphere, its particles interact with the water droplets in the clouds and with the ice of the glaciers and the poles, obscuring it; in addition, it accelerates its melting," he said.
Black carbon and methane emissions

The researcher, a member of the Intergovernmental Panel on Climate Change (IPCC, for its acronym in English), explained that human and planetary well-being is threatened by this phenomenon and by the degradation of air quality. "The current state of science emphasizes the urgent need to approach its study in a comprehensive manner."

Black carbon and tropospheric ozone remain in the atmosphere for a short time and are therefore considered Short Lived Climate Forcers (SLFC, short-lived climate agents).

The first is emitted by natural processes and human activities, by the incomplete combustion of fossil fuels, biofuels and biomass. "Primary sources of black carbon include diesel engines, small industrial sources, domestic carbon sources, solid biofuels for cooking and heating, and agricultural and forest fires," he said.

Meanwhile, methane (a precursor of tropospheric ozone) is the second cause of global warming, after carbon dioxide, and is included as one of the six greenhouse gases of the Kyoto Protocol.

The university student documented that atmospheric concentrations of methane have increased 2.5 times since the agro-industrial era, from about 700 parts per billion in 1800 to the global average concentration of 1,770 parts per billion in 2005, as a result of livestock. , rice cultivation, waste generation (landfills, manure and sewage), carbon mining, and oil and gas systems.

He also stated that the reduction of emissions of black carbon and methane can be obtained with existing technologies and will lead, in the short term, to significant benefits in health, crops, ecosystems and the climate.

"Despite these benefits, reducing global warming in the long term will require actions in the present to mainly reduce emissions of carbon dioxide, a pollutant that remains in the atmosphere for up to 150 years," he said.

The only fundamental strategy to end climate change is to reduce the emission of all pollutants, although some effects are seen in the short term and others are only perceived by the next generations, he concluded.

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Video: Characterizing the Climate Impacts of Brown Carbon (July 2021).