Pollution, especially in the form of certain air pollutants, can have negative effects on trees and their ability to fight infection. Air pollutants can damage leaf tissues, making them more susceptible to pathogens, and can also reduce the tree's overall health and vigor, making it less resilient to infection. Additionally, some pollutants can directly inhibit the tree's natural defense mechanisms against pathogens.

For example, sulfur dioxide (SO2), a common air pollutant emitted by power plants and industrial facilities, can cause damage to leaf tissues and reduce chlorophyll production, leading to reduced photosynthetic capacity. This can weaken the tree and make it more susceptible to infection. Similarly, ozone (O3), another common air pollutant, can cause leaf damage, reduce photosynthesis, and increase the tree's susceptibility to pests and diseases.

However, it's important to note that the relationship between pollution and tree health is complex, and the effects can vary depending on the type and concentration of pollutants, as well as the tree species and its overall health. Some studies have suggested that certain pollutants, in low concentrations, might have some stimulatory effects on plant growth, but this is not a consistent finding and the overall impact of pollution on tree health is generally negative.

Overall, pollution does not help trees fight infection, but rather hinders their natural defenses and makes them more susceptible to infection and other stressors.