[2] Although they remain largely unregulated, the World Health Organization has published good practice statements regarding measuring UFPs.
Electron microscopy and special physical lab conditions allow scientists to observe UFP morphology.
Owing to their large quantity and ability to penetrate deep within the lung, UFPs are a major concern for respiratory exposure and health.
Other UFPs are byproducts, like emissions, from specific processes, combustion reactions, or equipment such as printer toner and automobile exhaust.
[8] In 2014, an air quality study found harmful ultrafine particles from the takeoffs and landings at Los Angeles International Airport to be of much greater magnitude than previously thought.
[9] There are a multitude of indoor sources that include but are not limited to laser printers, fax machines, photocopiers, the peeling of citrus fruits, cooking, tobacco smoke, penetration of contaminated outdoor air, chimney cracks and vacuum cleaners.
[10] Certain UFPs like silver based nanostructures have antimicrobial properties that are exploited in wound healing and internal instrumental coatings among other uses, in order to prevent infections.
Contrary to the behaviour of inhaled PM10 and PM2.5, ultrafine particles are deposited in the lungs,[13] where they have the ability to penetrate tissue and undergo interstitialization, or to be absorbed directly into the bloodstream—and therefore are not easily removed from the body and may have immediate effect.
It has recently been reported that UFP is associated with an increase in blood pressure in schoolchildren with the smallest particles inducing the largest effect.
[22] In order to quantify exposure and risk, both in vivo and in vitro studies of various UFP species are currently being done using a variety of animal models including mouse, rat, and fish.