What can eye irritation from air pollution often signify?

Eye irritation from air pollution often signifies high levels of air pollutants. Air pollutants, such as particulate matter, sulfur dioxide, nitrogen oxides, and volatile organic compounds, can irritate the mucous membranes of the eyes, leading to discomfort or redness. When these pollutants are present in higher concentrations, they can trigger various eye-related symptoms, indicating exposure to poor air quality.

In contrast, high levels of humidity, increased vehicular traffic, and poor indoor air quality may contribute to or exacerbate eye irritation, but they are not direct indicators of air pollution as it pertains to the specific symptom of eye irritation. The presence of air pollutants is the primary factor that leads to noticeable effects on the eyes, making the correct answer focus on the pollutants themselves.