From using carbon-dating to place the age of fossils, to speculation on poly-cyclic aromatic hydrocarbons being the elemental foundation of life on earth, humans should have some kind of deep respect for carbon as the basic building block of life. Carbon is the center of our universe, except that it is everywhere and, perhaps, has no center. To the community health team at CAC, though, carbon isn’t exclusively the elemental foundation of existence from which all life emanates. To us, carbon is black: it is a particularly pesky carcinogenic aerosol produced by incomplete fossil fuel combustion. In other words, it is air pollution produced by vehicles that has the potential to cause cancer. As of this January, it also has the potential to make a clear political connection between human health and global climate change.
Black carbon is a form of particulate matter, a pollutant akin to dust, and also a particular form of carbon. Just as carbon sits at the foundation of life, black carbon sits at the foundation of human’s interaction with the environment. It has the power to affect human and non-human things alike, shaping urban environmental health, global climate change, and (potentially) technological innovation. Black carbon is a malleable substance, an accumulation of light-absorbing dust that is making new global environments in cities, oceans, forests, etc. There are three (two certain and one tentative) outward effects of black carbon we’ll go through here: its effect on human health; its contribution to climate change; and carbon’s potential as a new nano-technology.
Clean Air Council’s engagement with black carbon has mostly been with its effects on human health in cities. We know that it is primarily produced by diesel combustion and has the heaviest concentrations in places that, not surprisingly, also have high concentrations of diesel trucks. Having working in port neighborhoods in Philadelphia’s River Wards with quite a few of these trucks moving in and out of neighborhoods, we’ve worked on both measuring and reducing black carbon pollution in the city. It has many of the same health effects of particulate matter, ranging from heart disease, respiratory health, and cancer. Location matters, too. Particulates are smaller closer to the source and smaller particulates can reach further into your body, potentially causing more damage. Reducing particulate matter in cities will reduce mortality rates, improve health, and facilitate well-functioning urban bodies.
This January, atmospheric scientists released a report documenting the role of black carbon in global climate change. Previously, the top emission contenders for producing climate change were carbon dioxe (CO2) and methane. This report, however, identified black carbon as the second strongest contributor, now above methane but still below CO. Not all particles induce warming. Some, such as sulfate particles, are used in geo-engineering projects to create a cooling effect; lightly colored particles are released into the atmosphere, redirecting light and heat and dropping temperatures in the process. Black carbon emissions work in the exact reverse fasion: dark particles absorb light and heat, increasing temperatures and affecting the earth’s large-scale weather patterns.
Researchers at NASA have developed carbon nano-tubes that have a wide array of applications. They are high-strength, light absorbing tubes with the potential to produce, high efficiency batteries, ultra-black coatings for stealth fighter jets, and cooler running electronic appliances. They same light and heat absorbing properties that allow black carbon to induce global warming. On a smaller scale, though, nano-tubes produce an ultra-black coating that can absorb around 99% of the light they encounter. This allows nano-tubes to cloak objects from radars (which use a specific portion of the light spectrum) and coat the wires we use in heat-producing everyday electronic products. I’m unsure if carbon nano-tubes are produced from the same carcinogenic materials as black carbon, but their names and physical properties bear a striking resemblance.
Carbon, in its many forms presented here, is an important material thread connecting urban public health, climate change, and (potentially) new technologies. It has only been in the last few years that CO2, the largest contributor to climate change, has been formally identified as a threat to human health under the U.S. Clean Air Act and thus allowing the U.S. government to put real limits on the amount of national CO2 emissions. This has taken much debate, though, on the validity of climate change science and CO2’s role in affecting weather patterns and thus human health. The health effects of black carbon and particulate matter, though, are much more certain. So, at the same time that we (cautiously?) proceed with carbon-based tech development, a continued push to reduce urban particle concentrations now has a growing political and physical connection to climate change. In other words, reducing black carbon emissions will improve local health and reduce global warming. Win-win?