Researchers from the Harvard School of Public Health measured the levels of toxic gases upwind, downwind at loading docks, mechanic shops, and inside truck cabs while in heavy traffic. They found formaldehyde, acetaldehyde, EC, benzene, and 1,3-butadiene frequently at concentrations exceeding the EPA’s screening values.

Smith TJ; Davis ME; Hart JE; Blicharz A; Laden F; Garshick E; Potential Air Toxics Hot Spots in truck terminals and cabs. (2012, December). https://pubmed.ncbi.nlm.nih.gov/23409510/

“Infectious diseases that can be transmitted between animals and humans are called zoonoses. According to the CDC, roughly 60 percent of all known human infectious disease agents originate in animals, including Brucella, HIV, Salmonella, and rabies virus. Most new or emerging infectious diseases in humans are zoonotic in origin (e.g., COVID-19, Ebola, and highly pathogenic avian influenza), with about 80 percent of potential bioterrorism threats being zoonotic (e.g., anthrax and plague).”

Smith TJ; Davis ME; Hart JE; Blicharz A; Laden F; Garshick E; Potential Air Toxics Hot Spots in truck terminals and cabs. (2012, December). https://pubmed.ncbi.nlm.nih.gov/23409510/

According to the Centers for Disease Control and Prevention, the manufacturing of both pleather and leather utilizes toxic chemicals in their creation which are infused in the materials. Risks of exposure include eye/nose/throat irritation, respiratory issues, organ damage, or cancer.

A wealth of information may be found on the CDC Website https://search.cdc.gov/search/?query=leather&dpage=1