Mechanisms of ultrafine particle-induced respiratory health effects

Abstract

Respiratory disease: Effects of airborne ultrafine particles The ultrafine particles (UFPs) in air pollution aggravate respiratory illnesses via oxidative stress and inflammation, according to a review by South Korean and US researchers. Defined as particles less than 100 nm in diameter, UFPs are about 1/1000(th) the thickness of a human hair. Inhaling UFPs is known to aggravate respiratory illnesses such as asthma, but the mechanisms remain poorly understood. An-Soo Jang at Soonchunhyang University Bucheon Hospital, Korea and co-workers have reviewed the evidence on how UFPs harm the airways. They report that UFPs are readily deposited in the lungs, where they trigger production of reactive oxygen species, highly reactive molecules that cause cellular and DNA damage. UFPs also provoke airway inflammation, and long-term exposure can scar the lungs. These results will aid in protecting at-risk individuals from the harmful effects of air pollution. Particulate matter (PM) is the principal component of air pollution. PM includes a range of particle sizes, such as coarse, fine, and ultrafine particles. Particles that are <100 nm in diameter are defined as ultrafine particles (UFPs). UFPs are found to a large extent in urban air as both singlet and aggregated particles. UFPs are classified into two major categories based on their source. Typically, UFPs are incidentally generated in the environment, often as byproducts of fossil fuel combustion, condensation of semivolatile substances or industrial emissions, whereas nanoparticles are manufactured through controlled engineering processes. The primary exposure mechanism of PM is inhalation. Inhalation of PM exacerbates respiratory symptoms in patients with chronic airway diseases, but the mechanisms underlying this response remain unclear. This review offers insights into the mechanisms by which particles, including UFPs, influence airway inflammation and discusses several mechanisms that may explain the relationship between particulate air pollutants and human health, particularly respiratory health. Understanding the mechanisms of PM-mediated lung injury will enhance efforts to protect at-risk individuals from the harmful health effects of air pollutants.