Research progress on influence of PM_2.5 on allergic rhinitis

Allergic rhinitis (AR) is one of the main chronic inflammatory diseases that pose a global threat. Its symptoms persist for a long time, recur, and seriously affect the physical and mental health of the patients. Existing research has shown that the occurrence and development of AR are related to genetic and environmental factors. In recent years, the harm of air pollution to human health has received increasing attention, and fine particulate matter (PM_2.5) is the main harmful component of air pollutants. Its small particle size makes it easy to absorb various harmful substances, enter the respiratory tract, damage the nasal mucosa, and participate in the occurrence and development process of AR. At present, a large number of epidemiological studies have confirmed that PM_2.5 is positively related to the incidence rate and severity of symptoms of AR, but its exact mechanism is still unclear. Therefore, studying the mechanism of PM_2.5 exposure on AR damage is expected to provide new clues for exploring the pathogenesis and deterioration of AR. This article reviewed the epidemiological studies and toxicological mechanisms of PM_2.5 exposure and AR in recent years; discussed the potential biological mechanisms of PM_2.5 induced AR occurrence and development, including nasal mucositis damage, oxidative stress, and immune damage. Furthermore, a new research direction was proposed, which suggested that neuroimmune disorders and bacterial imbalance may be involved in the progression of AR and play a certain role in the toxic effects induced by PM_2.5. We aim to provide ideas and a theoretical basis for developing effective measures to prevent and treat AR.