Carbon (Graphite/Carbon Black)

Carbon black is produced by the incomplete combustion or thermal decomposition of petroleum products — a process refined industrially since the late 1800s when it replaced lampblack as a rubber reinforcing agent [1]. Over 90% of carbon black production goes into rubber vulcanization for tires; the remainder goes into printing inks, plastics pigmentation, and as a UV stabilizer in outdoor plastics [2]. Natural soot — chemically similar to carbon black — is produced by any combustion process: diesel engines, wood burning, coal combustion, and wildfires. Graphite, the crystalline form of carbon, is mined and used in lubricants, pencils, electrodes, and increasingly in lithium-ion batteries [1]. IARC classifies carbon black as Group 2B (possibly carcinogenic to humans) and Group 1 for soot; EPA lists carbon black as a hazardous air pollutant at certain particle sizes [2].

Occupational inhalation of carbon black dust in tire manufacturing, rubber production, and printing ink manufacturing represents the primary high-dose exposure pathway [1]. General population exposure occurs through ambient fine particulate matter (PM2.5): diesel exhaust, wood smoke, and coal combustion all release carbon black-like particles that penetrate the deep lung [2]. Urban residents near highways, bus depots, or port facilities breathe elevated concentrations of combustion-derived carbon particles [1]. Graphite exposure occurs in battery manufacturing, electrode production, and among those who use graphite-lubricated products. Nano-scale carbon black in some consumer products (coatings, composites) may be dermally absorbed [2].

The health concern with carbon particles is primarily size-dependent: ultrafine carbon particles (< 0.1 µm) penetrate alveolar walls and enter the bloodstream, reaching the heart, brain, and placenta [1]. This translocation is associated with cardiovascular effects — fine particle exposure (which includes carbon black) is the best-established environmental cause of premature cardiovascular death, contributing to over 4 million deaths globally per year [2]. IARC's Group 2B classification for carbon black reflects evidence of lung tumors in rats exposed to very high occupational doses, with uncertain extrapolation to human cancer risk at environmental levels [1]. Graphite dust causes pneumoconiosis (graphite lung disease) after heavy occupational exposure — a fibrotic lung disease similar to coal worker's pneumoconiosis [2].

Tire manufacturing and carbon black production workers face the highest carbon black dust exposures [1]. Printing industry workers are also occupationally exposed. Urban residents near highways and freight corridors breathe combustion-derived carbon particles at concentrations associated with cardiovascular and respiratory harm [2]. Children living near diesel truck routes have higher rates of asthma and impaired lung development — PM2.5 (of which carbon black is a major component) impairs lung growth during childhood [1]. Battery factory workers in the lithium-ion manufacturing boom are now a growing category of graphite exposure [2].

1. Use a HEPA air purifier in bedrooms — fine particles including carbon black from traffic penetrate indoors, and purification reduces indoor PM2.5 by 50-80% [1]. 2. Check your area's air quality index (AQI) daily using AirNow.gov; on days when PM2.5 is elevated (AQI > 100), reduce outdoor exercise near traffic and keep windows closed [2]. 3. If you live near a highway or freight corridor, consider bedroom placement on the far side of the building from traffic to reduce exposure during the hours spent sleeping. 4. For outdoor exercise, choose parks and greenway routes away from heavy traffic rather than along arterials [1]. 5. Support policies targeting diesel truck fleet electrification and low-emission zones in dense urban areas — these have the largest impact on community carbon particle exposure [2]. 6. If you work in tire or carbon black manufacturing, advocate for engineering controls and use NIOSH-approved respirators rated for fine particulate matter [1].