The eyes, being particularly sensitive to chemical irritants, are another area of concern.
"Long-term exposure or close-range exposure to teargas can cause blindness due to damage to the optic nerve (traumatic optic neuropathy), bleeding (subconjunctival bleeding), cataracts (traumatic cataract), corneal erosion and chemosis (swelling of the lining of the eye)," a report by UM Surabaya University's Faculty of Medicine says.
According to Dr Ezekiel Mecha, a Senior Lecturer in the Department of Biochemistry at the University of Nairobi and a certified Global Consultant in Biorisk Management and Biosecurity, the duration and spread of tear gas depend on several factors:
"Inside or outside closed area. It also depends on the weather conditions. In cold, humid and calm conditions it takes longer to clear unlike in opposite conditions," he says.
The Biochemist adds that the amount of gas released also determines the clearance rate - one canister or more.
"Tear gas can take 3 to 5 hours to clear, that again dependent on the prevailing weather conditions and how many canisters released," he says.
He adds that in cold and calm (non-windy) and enclosed conditions, it can take several days.
If several canisters are used, it may take up to two days to clear.
Dr Mecha notes that individual reactions to tear gas vary, similar to how people respond differently to onion odours. Tear gas, being heavier than air, tends to settle on the ground unless dispersed by wind. It also adheres to materials like clothing.
A study published in the journal Reproductive Toxicology found that exposure to high levels of CS gas in pregnant mice led to an increased risk of miscarriage and fetal abnormalities.
However, the Hong Kong Medical Journal states there is limited data on the effects of acute exposure to tear gas during pregnancy.
The use of teargas in warfare was banned by the Chemical Weapons Convention of 1993, which prohibited the use of riot control agents as a method of warfare. However, its use in domestic law enforcement remains legal in many countries, including Kenya.
Human rights organisations have called for stricter regulations on teargas use. "The potential long-term health effects underscore the need for more restrained and proportionate policing methods," states Amnesty International Kenya spokesperson Irungu Houghton.
As the smoke is yet to clear, the conversation about balancing public safety with the right to peaceful demonstration continues.