The health effects of ultrafine particles

Abstract

Ultrafine particles (PM _0.1), which are present in the air in large numbers, pose a health risk. They generally enter the body through the lungs but translocate to essentially all organs. Compared to fine particles (PM _2.5), they cause more pulmonary inflammation and are retained longer in the lung. Their toxicity is increased with smaller size, larger surface area, adsorbed surface material, and the physical characteristics of the particles. Exposure to PM _0.1 induces cough and worsens asthma. Metal fume fever is a systemic disease of lung inflammation most likely caused by PM _0.1. The disease is manifested by systemic symptoms hours after exposure to metal fumes, usually through welding. PM _0.1 cause systemic inflammation, endothelial dysfunction, and coagulation changes that predispose individuals to ischemic cardiovascular disease and hypertension. PM _0.1 are also linked to diabetes and cancer. PM _0.1 can travel up the olfactory nerves to the brain and cause cerebral and autonomic dysfunction. Moreover, in utero exposure increases the risk of low birthweight. Although exposure is commonly attributed to traffic exhaust, monitored students in Ghana showed the highest exposures in a home near a trash burning site, in a bedroom with burning coils employed to abate mosquitos, in a home of an adult smoker, and in home kitchens during domestic cooking. The high point-source production and rapid redistribution make incidental exposure common, confound general population studies and are compounded by the lack of global standards and national reporting. The potential for PM _0.1 to cause harm to health is great, but their precise role in many illnesses is still unknown and calls for more research.

Air pollution: Nanoparticles linked to disease

Tiny particles found in air pollution enter the body usually through the lungs and disperse to other organs, causing more inflammation and cellular toxicity than larger particles. Dean Schraufnagel from the University of Illinois at Chicago, USA, reviews the way by which nano-sized air pollutants threaten human health. He describes how ultrafine particles measuring less than 100 nanometres in diameter elicit greater inflammatory responses and stay in the lungs longer than larger particles. Repeated contact with extremely small particulate matter can trigger heart disease, diabetes, cancer, neurological disorders and respiratory ailments, especially among children and people with long-term occupational exposure. Much remains to be learned about the disease-causing properties of these nanoparticles and their long-term effects. Further developments in understanding remain handicapped by the lack of international standards and reporting measures.