The concentrations of hydrocarbons and nitric oxide in the surrounding air affect how uncomfortable air pollution is.
C4 and C5 olefins are two hydrocarbon compounds that are particularly well-known for producing such discomfort. Compared to straight chains, branched hydrocarbons have more of an impact on the eyes, particularly if the chain has some double bonds that aren’t close to the terminal carbon. When compared to paraffin, olefins significantly increase irritation.
Among phenolic chemicals, cyclohexene causes the highest discomfort as compared to benzene or cyclohexane.
The main cause of air pollution is the radiation from vehicle exhaust. When exposed to this level of air pollution for up to four hours, there is a substantial amount of eye irritation.Despite changes in relative humidity (between 30% and 80%) or temperature (25 to 45 oC), the irritants in irradiated car exhaust likewise don’t change.
Although the cause of eye irritation and the particle size in automotive exhaust are still unknown, one researcher has found that discomfort is largely averted below 0.2 microns. It is believed that the make and performance of the motor vehicle determine the emission of hydrocarbons and nitric oxide; however, individual hydrocarbon levels depend more upon the type of fuel used. These two substances both irritate the eyes in the same way.Subthreshold quantities of sulfur dioxide and trioxide interact with sodium chloride or carbon black particles to cause irritation.
Another study found a connection between seasonal variations in ocular irritation and the amount of oxidants in the air. Another important consideration is said to be the existence of aerosol. Oxidants have the ability to dissolve in the tear film, making it acidic and aggravating the eye’s mucous membrane even more.
Among the air contaminants that are frequently observed in large cities are:
Carbon monoxide (CO)
Nitrogen dioxide (NO)
Sulfur dioxide (SO2)
Arsenic, asbestos, benzene, lead, chlorofluorocarbons, particulate matter, and dioxin
