What type of air pollution is known to cause loss of chlorophyll in plants?

The type of air pollution that is known to cause loss of chlorophyll in plants is peroxyacetyl nitrate (PAN). This compound is a photochemical oxidant formed in the atmosphere as a result of various reactions involving nitrogen oxides and organic compounds, particularly in the presence of sunlight. When plants are exposed to PAN, it can lead to damage in the chloroplasts, the cellular structures responsible for photosynthesis. This damage results in reduced chlorophyll content, impairing the plant’s ability to carry out photosynthesis effectively.

Chlorophyll loss can manifest as chlorosis, where the leaves of the plant turn yellow and exhibit stunted growth. Since chlorophyll is essential for photosynthesis, its reduction affects the overall health and productivity of plants. This makes understanding the effects of PAN vital in environmental health, especially in areas with significant vehicular emissions and industrial activity.

While other pollutants like sulfur dioxide can also harm plants, their primary effects differ from those caused by PAN. Sulfur dioxide, for example, tends to cause direct leaf injury and is more associated with acid rain than with chlorophyll loss. Therefore, focusing on PAN highlights the importance of understanding different types of air pollutants and their specific impacts on vegetation.