What are ecotoxicological effects of air pollution?

The correct response highlights the adverse effects of pollutants on ecosystems, which is a critical aspect of ecotoxicology. Ecotoxicological effects include harm caused by various pollutants to organisms and the habitats they rely on. This can manifest in several ways, such as toxicity leading to declines in population numbers of sensitive species, disruption of reproductive processes, and heightened susceptibility to disease. Additionally, air pollution can degrade habitats, making them less hospitable for wildlife and leading to a loss of biodiversity and ecological balance.

In contrast, the other options do not align with the realities of air pollution's impact. Air pollution is unlikely to have positive impacts on ecosystems, as it generally disrupts the natural processes that sustain them. Similarly, improved biodiversity is not a typical outcome of increased pollution; rather, biodiversity often suffers as pollution can harm or eliminate species. Lastly, the reduction of harmful substances in the ecosystem is not an effect of air pollution; instead, air pollution introduces harmful substances that can linger in the environment and have severe long-term effects on both the organisms within and the overall health of ecosystems.