An Overview of Black Carbon Pollution


Every year, millions of people die prematurely from prolonged exposure to air pollution. Harmful air pollution levels are pervasive outdoors, in homes, and at the work place. Over 90% of the world’s population lives in areas where ambient air pollution levels exceed the WHO’s acceptable limits.   

Air pollution is a mixture of toxic gases and particulate matter (PM). Particulate matter consists of microscopic solid and liquid particles suspended in the air. These particles are many times smaller than a grain of table salt, measuring around 10 micrometers or less in diameter, which allows them to infiltrate the deepest regions of the lungs and transport toxic compounds into the bloodstream. When inhaled, these particles damage the respiratory and cardiovascular systems, and increase the incidence of associated illnesses and premature death. Vulnerable populations, such as infants and the elderly, are particularly susceptible to adverse health impacts from air pollution exposure.

What is black carbon?

Black carbon (BC) is the light absorbing component of particulate matter (PM) pollution emitted during the combustion of biomass and fossil fuels. Common sources include:

  • Diesel engines used in transportation or industry

  • Wildfires

  • Biomass (e.g. wood) heaters and cookstoves

  • Petrochemical refineries and other industrial processes

Black carbon is only emitted during incomplete fuel combustion: When black carbon is detected in the atmosphere, something is certainly burning upwind of the measurement location. These combustion emissions are hazardous to human health and damaging to the environment. In most contexts, air quality levels are driven by transportation, industry, agriculture, wildfires, and other combustion sources. Since black carbon is specifically associated with combustion, it serves as a strong proxy by which to detect harmful polluters, and accurately quantify their impact on surrounding communities and ecosystems. Black carbon also impacts the environment directly: it reduces visibility, affects snow packs, and is a major driver of climate change.

Health impacts

Black carbon is a marker for combustion emissions that are highly toxic and harmful to human health. For example, exposure to indoor air pollution from solid biomass combustion (particularly cookstoves fueled by wood or charcoal) is the world’s greatest environmental health risk, causing nearly 4 million premature deaths annually. Prolonged exposure to outdoor air pollution is also a major health burden, resulting in over 3 million premature deaths every year. Harmful ambient pollution levels are particularly pervasive in urban areas affected by combustion emissions from transportation, industry, and electric power generation: In 2010 premature deaths attributable to ambient air pollution exposure were about 50% more common in urban than in rural settings, and this could increase to 90% by 2050 if current trends continue.

Combustion processes emit very fine particulate matter composed of poisonous compounds. Inhalation of these particles and associated toxic gases is strongly linked to increased prevalence of heart disease, respiratory infections, stroke, heart attack, and chronic respiratory conditions such as asthma. It is also responsible for infant mortality from acute respiratory infections. While the health effects of black carbon itself are still not entirely clear, exposure to air pollution from combustion sources, such as cookstoves or diesel engines, has long been established as a major public health burden.

Climate impacts

Black carbon is also a short-lived but powerful climate forcer in the atmosphere: Only carbon dioxide contributes more to global radiative forcing. Black carbon only remains suspended in the atmosphere for about a week after emission (it is primarily removed by the hydrological cycle, through rainfall etc.), but per unit mass, it’s climate forcing potential is many times stronger than CO2 and other common greenhouse gases.​ When suspended in the atmosphere, black carbon particles contribute to climate change by absorbing incoming solar radiation and releasing it as heat to the surrounding environment. Since black carbon can serve as a nucleation site for precipitation, it also affects cloud formation, regional wind circulation, and rainfall patterns. 

When black carbon pollution deposits on ice and snow, it darkens the surface and reduces sunlight reflection. As a result, the snow and ice absorb more heat and melt faster than they would otherwise. Polar and alpine regions such as the Himalayas are particularly vulnerable to decreased snow pack, retreating glaciers, and warming as a result of black carbon pollution.

Black carbon can affect rainfall patterns, with potentially severe consequences for ecosystems and livelihoods. For example, black carbon pollution is likely disrupting monsoon cycles in Southeast Asia, which are absolutely critical to agriculture in the region.  

Our black carbon monitoring technology

Black carbon has many dangerous impacts that cannot be overlooked. At Distributed Sensing Technologies, we develop cutting edge technologies (such as the ObservAir series) to monitor black carbon in areas and contexts where this was previously unfeasible or unaffordable. By leveraging the atmospheric data our technology collects, we can work with cities, industries, and communities to understand and quantify the air pollution challenges that we face. Our technology is designed from the ground up as an accessible, dependable toolset that enables stakeholders to formulate, implement, and validate public policies that better protect the air we share. Contact us today!