The most dangerous opponent is one that we don’t feel attacking us directly. We don’t actively fight what we don’t perceive as a threat. The quality of the air we breathe is sadly becoming a dangerous opponent to our good health. Toxic air pollution has become so ubiquitous in our modern world, and we truly underestimate how harmful it really is.
It’s no secret: Particulate matter is a serious public health issue. Most particulate matter results from chemical reactions between two or more pollutants. The result is an atmospheric stew of harmful substances in the air we breathe, whether in our own homes or on the streets. As defined by the United States Environmental Protection Agency, “Particulate matter, also known as particle pollution, is a complex mixture of tiny particles and liquid droplets that get into the air. Once inhaled, these particles can affect the heart and lungs and cause serious health effects.”(1) One of the most common types of particulate matter is black carbon.
Of note here is that the heart and lungs are mentioned by name. What’s missing from this simple definition is that particulate matter - specifically black carbon - can bond with heavy metals in the environment and be absorbed into the liver, potentially causing severe harm to the body’s internal organs. (2)
What Is Black Carbon?
Black carbon is the sooty black material emitted from gas and diesel engines, coal-fired power plants, and other sources that burn fossil fuel. It comprises a significant portion of particulate matter, which is an air pollutant. Black carbon consists of pure carbon in several linked forms. Black carbon is formed naturally and also from modern human activities. It is formed through the incomplete combustion of fossil fuels, biofuel, and biomass, and is emitted in both anthropogenic and naturally occurring soot. (3) Black carbon health effects cause human morbidity and premature mortality. It is also becoming a major catalyst to global climate change, rivaling only CO2 as the main contributor to the change. (4)
What Is The Source Of Black Carbon?
Unfortunately, black carbon and the heavy metals attached to it aren’t easy to get away from. We are subjected to it regularly on differing levels. Humans are exposed to black carbon by inhalation of air near local sources. Important domestic sources include candles and that cozy firepit you have in your backyard, or biomass burning. Other sources include traffic and the occasional fire, forest fire, or other similar occurrences. These are the primary outdoor sources of black carbon exposure and heavy metals. Black carbon soot also comes from coal, tars, furnaces, and to a small extent halogen bulbs.
Concentrations of black carbon decrease sharply with increasing distance from (traffic) sources which makes it an atypical component of particulate matter. This makes it difficult to estimate exposure of populations. For particulate matter, epidemiological studies have traditionally relied on single fixed-site measurements or inferred residential concentrations. (5) Recent studies have shown that most black carbon is inhaled in traffic and at other locations as at one’s own home. (6) High or peak concentrations are encountered during car driving. High in-vehicle levels of black carbon have been associated with driving during rush hour, on highways and in dense traffic. (7) This corroborates the assumption that those who live in more urban, densely-populated areas are at higher risk for toxicity from black carbon (PM2.5) and associated heavy metal toxicity than those who live in more rural areas. Black carbon is a global environmental problem that has negative implications for both human health and our climate.
How Can Black Carbon Impact Human Health?
Black carbon health effects have been documented for three centuries. In 1775, a London surgeon named Sir Percival Pott made the connection that chimney sweepers were particularly susceptible to developing cancer. (8) He surmised that soot was the first environmental factor in causing cancer. Hundreds of studies have since proven his suspicions, soot and black carbon are dangerous carcinogens.
One of the reasons that black carbon promotes cancer is that it changes DNA methylation. Black carbon can alter DNA methylation and changes the expression of specific genes towards developing cancer. (9)
As we have already established, black carbon and the heavy metals associated with it have a massive negative impact on the body right down to the cellular level. Studies suggest that other cellular black carbon health effects include: increased intracellular reactive oxygen species, reduced glutathione, mitochondrial dysfunction, increased cell death rate, and DNA damage. (10) Our bodies naturally strive to restore health, but black carbon can break DNA and prevent it from repairing itself. (11)
Black carbon can also contribute to cardiovascular disease. (12) Short-term exposure to high levels of air pollution leads to higher risk of heart attack. (13) Black carbon effects prove to be even more dangerous to the hearts of those not eating a healthy diet. The black carbon particles greatly accelerated the “aging” of the cells that line the heart. (14)
The lungs are the first inner tissue to be exposed to black carbon when we inhale. Black carbon can have immediate effects on the lining of the lungs and generate cell death in the bronchial epithelial cells. (15) Respiratory disorders and increased risk of developing asthma was found to be higher from black carbon specifically when compared to particulate matter in general. (16) Exposure to black carbon and heavy metals in the lungs can spread throughout the body, and studies suggest it creates inflammation in the brain. (17)
The liver is a vital organ involved in digestion, hormones, and detoxification. Particulate matter, black carbon, and heavy metals impair its ability to function properly and can create liver toxicity. (18) The liver is designed to protect us from these harmful substances. But the long-term inflammation and DNA damage from the black carbon can render the liver unable to detoxify us effectively. The liver is also involved in glucose metabolism. Studies suggest that high exposure to black carbon can induce insulin resistance, independent of a person's weight. (19) Insulin resistance can be a precursor to type 2 diabetes.
Black Carbon Effects The Unborn
Sadly, the adverse health effects of black carbon can begin before a person is born. Even before conception since black carbon is linked to lower sperm count. (20) Researchers have discovered black carbon in the placenta of healthy non-smoking mothers. (21) Unborn babies whose mothers had higher exposure to black carbon and air pollution can have lower birth weight, smaller head circumference, and were sometimes born prematurely. (22) Studies also suggest that being exposed prenatally can have a harmful impact on neurological function. (23) These cognitive issues seemed to be greater in males than females. (24) Black carbon and heavy metals seem to be able to be transferred from mother to offspring and break liver DNA. (25)
Heavy Metals: Black Carbon’s Sidekick
As we’ve demonstrated, black carbon can generate serious health issues all by itself. It carries a long list of potential damage. Unfortunately, it’s not the only particle we are exposed to or inhale. Black carbon attracts heavy metals to its surface bringing more potential harm to our bodies.
The inorganic, metallic heavy metals like aluminum, arsenic, mercury, cadmium, and lead are not beneficial for the body. In fact, these heavy metals disrupt normal metabolic functions. (26) They increase inflammation, create a surge of reactive oxygen species, and inhibit needed enzymes from working. Aluminum, for example, interferes with the vast majority of physical and cellular functions. It blocks enzymes that are required by our DNA and RNA. It has a greater ability to attach itself to the cell than our enzymes. It accumulates in the brain and creates lesions similar to those found in Alzheimer's patients. Arsenic deteriorates our blood vessels, leads to skin lesions, promotes liver and lung diseases as well as cancer. (27) Mercury induces mitochondrial and kidney damage. Like aluminum, seems to favor settling in the brain generating neurological problems. (28) Cadmium also negatively affects enzymes within the cell and creates oxidative damage. Cadmium concentrations skyrocket 3,000 times as it binds with cysteine; this produces liver toxicity which circulates to the kidneys accumulating there as well. Cadmium binds to other amino acids that could induce iron deficiency. Lead is particularly dangerous as a cofactor with black carbon because its absorption rate is magnified when breathed in rather than through other exposures. (29) When lead assimilates into the body, it accumulates in our blood, tissues, and bones. 95% of lead ends up in our bones. (30) As cells change over, the lead is again released chronically poisoning us. Because of this, postmenopausal women have higher levels due to their bones demineralizing faster than perimenopause. (31) Chronic lead exposure can lead to impaired growth, allergies, autism, lower IQ, and edema in the brain. (32)
With all the risk around heavy metals, it is important to remember that some heavy metals are needed in the body in small amounts for good health. These include iron, zinc, copper, chromium, and manganese. But they also need to be in a form that is bioavailable to our tissues, preferably from plant sources. High levels of these less bioavailable heavy metals can get into our bodies alongside the black carbon. When this happens, toxicity develops rather than optimum health.
How Does Black Carbon Affect The Environment?
Research on how black carbon effects the environment is an ongoing focus for scientists. They estimate that it has a lifespan in the atmosphere of around 4-12 days. CO2 stays in the atmosphere from decades to centuries. Black carbon may be in the atmosphere for a fraction of the time, but make no mistake - it is a huge factor in global warming. It has a fantastic affinity to absorb light and heat its surroundings. In fact, per unit of mass, black carbon is 460-1,500 times stronger in its ability to warm than CO2. (33) While suspended in the air, black carbon absorbs solar radiation and turns it into heat. This can change cloud formation and influence rainfall trends. Black carbon can fall on ice in Arctic regions and promote melting because of the increased warmth. The increased warmth can prevent the ice from reflecting the sun’s rays, absorbing them instead. Not only does this promote the melting of the ice sheets, but algae also starts to grow on the ice. Some algae growth is normal, but the higher temperatures lengthen its growing season. Algae also help to melt the ice, so increasing the algae growth compounds the problem.
Another environmental effect that must be considered with black carbon is animals. Most mammals have similar organ and cellular systems to humans. If our cell and organ processes are being corrupted by black carbon and heavy metals, it’s safe to assume that theirs are being impacted as well. This could disrupt animal populations as well as biodiversity. With global warming changing ecosystems, the delicate balance of prey to predators is at risk. Predators may be forced to hunt for different sources of food, altering these natural balances even further. (34)
The Benefits of Black Carbon Awareness
Becoming educated on the health effects of black carbon and heavy metal toxicity shouldn’t scare us. It’s just unveiling the facts of this growing, yet mostly silent opponent. Now we can focus on being proactive by discovering ways to reduce black carbon and protecting ourselves, our loved ones, and the environment.