Ozone exposure is linked to respiratory illnesses such as asthma and lung inflammation. Extended ozone exposure can exacerbate existing respiratory ailments such as chronic bronchitis and emphysema. Ozone pollution can severely damage vegetation including agricultural crops and forest habitats. Nitrogen oxides are precursors for ozone, and in the environment, they contribute to the formation of acidic rain. Hydrocarbon emissions are a product of partial fuel combustion, fuel evaporation and refueling losses caused by spillage and vapor leakage.
Hydrocarbons react with nitrogen oxides and sunlight to form ozone.
Some hydrocarbons are toxic and may be carcinogenic.