Black Carbon

Black carbon is produced from incomplete combustion of organic matter. It comes in a range of forms from soot to charcoal. The aim of this post is to outline the environmental impacts from black carbon; these include both climate and health effects.

Highwood and Kinnersely (2006) suggest 4 ways in which black carbon can impact climate:

1. Direct effect: Black carbon absorbs solar radiation affecting the earth’s albedo. This reduces the solar radiation that reaches the surface and contributes to global dimming and surface fluxes of heat and moisture.
2. Indirect effect: Black carbon within other aerosols affects the microphysics of clouds, changing droplet size and frequency of precipitation
3. Semi-direct effect: Studies of the Indian ocean and South America indicate black carbon increases the atmospheric heating rate and alters humidity. This then affects whether clouds can form and persist
4. Indirect surface albedo effect: Deposition of black carbon on snow and ice can cause them to melt and lead to warming, particularly in the northern hemisphere. The deposits darken the surface and decreases reflectivity i.e. increasing absorption and accelerating melting of ice and snow cover.  

The World Health Organisation reported on the health effects of black carbon in 2012:

• Ischaemic heart disease
• Adult on-set of asthma
• Atherosclerosis
• Heart rate variability
• Arrhythmia
• Blood pressure
• May reduce air quality, causing heavy smog and carrying toxic chemicals to the lungs, defence cells and systemic blood circulation (Highwood and Kinnersely, 2006) – e.g. the Great Smog of London, which lead to an approximated upper bound of 10,000 premature deaths

Black carbon is widely thought to have contributed to global warming and many premature deaths. Thus, there has been a demand for cleaner air quality and less black carbon emissions. Next post we will begin to look at the economic implications of one method of controlling such emissions.