Air Pollution and Headache Disorders.

Air pollution, the most prevalent form of pollution worldwide, is associated with a wide range of neurological disorders, including neurodegenerative conditions, stroke, autism, depression, and developmental delay. There is accumulating evidence on the association between air pollution and headache disorders, especially migraine. Many classical and non-classical air pollutants have been associated with headache, including particulate matter, nitrogen dioxide, sulfur dioxide, ozone, carbon monoxide, as well as polycyclic aromatic hydrocarbons and volatile organic compounds. There has also been research on the impact of biomass fuels on health-related symptoms, including headache, which form an important source of air pollution in our country. The exact mechanisms underlying headache pathophysiology vis-à-vis air pollution are not precisely defined but include triggering of neuroinflammation and activation of the transient receptor potential ankyrin 1 (TRPA1)-associated pathways. Evidence from different regions of the world indicates a significant association between headache incidence and prevalence, and occurrence of air pollution. Despite growing data, research on adverse effects of air pollution on headache disorders remains limited, and appropriate outcome measures are not holistically defined in these studies. Due to the rapid advancement of the scourge of air pollution, there is a pressing need to expand the arena of research, specifically focused on pathological mechanisms, impact on health and quality-of-life parameters, as well as broader global ramifications.