Genspect

Making it happen

Ozone  (O₃)

Ozone has the chemical formula O3 and is comprised of three oxygen atoms, O=O-O. An allotrope of oxygen, ozone is a light blue, almost colorless gas at standard temperature and pressure. At concentrations of 1 ppm, ozone can smell like sulfur; at weaker concentrations, the gas is nearly odorless. In nature, ozone is produced by photolysis of oxygen in the stratosphere and by lightening. The German chemist Christian Schönbein discovered ozone in 1840. Its name derives from the Greek word ozein, meaning ‘smell,’ and it is often detected after electrical storms.

Effects on Humans

Ozone plays a crucial role in Earth’s upper atmosphere by preventing lethal ultraviolet rays (320 nm and under) from reaching the ground. At the surface, ozone is toxic to living organisms. Ozone is harmful to the lungs and impairs respiratory function. Acute exposure to 0.25 to 0.75 ppm can cause difficulty breathing, chest constriction, fatigue, dizziness, headache and nausea. Ozone converts cholesterol to plaque, causing arteriosclerosis, and may be a contributing cause of Alzheimer’s disease. Prolonged exposure to high concentrations (50 ppm and over) is potentially fatal.

High voltage equipment, including photocopiers and laser printers, produces ozone in significant amounts. In industry, ozone is produced by passing a high voltage current through a cell of O2 gas molecules or dry air. More reactive than oxygen, ozone is used commercially as a disinfectant for organic compounds, including water, fruits and vegetables. Ozone is used to sterilize air and surfaces in food-processing plants. It is also a cleaner and bleaching agent for textiles and an agent in plastics manufacturing that facilitates bonding of ink. In hospitals, ozone is used to sterilize operating rooms, and ozone has medicinal uses as a stimulant of antioxidant enzymes.

Ozone and Climate Change

Tropsopheric increases of O3 concentrations (30% since industrialization) cause variable forcing that reaches 1Wm-2 in northern mid latitudes. Air-quality implications are serious, with background levels as high as 80 ppb in rural and urban regions. Tropospheric sources and sinks are difficult to quantify, and recent trends are difficult to infer from current measurements. O3 has a molecular lifetime in the order of weeks, and the reactive nature of ozone prevents paleoclimatic analysis of longer-term trends from ice cores. The tropospheric chemistry of O3 is closely tied to the free radical OH.

Depletion of stratospheric ozone has been a significant concern since the 1970s, when scientists observed a higher incidence of skin cancer among people living at lower latitudes where stratospheric ozone is less abundant. At this time, the U.S. federal government suspended plans for the commercial manufacture of supersonic aircraft amid concerns that nitric oxide emissions from the fleet flying at 20 km altitudes would deplete stratospheric ozone by 3%. Recognition of the depleting effects of chlorofluorocarbons (CFCs) soon followed, and production of CFCs used in aerosol sprays, refrigerants and other applications decreased significantly between 1975 and 1982. Current research focuses on ozone depletion in relation to abundances of CFCs, carbon monoxide, nitrous oxide and methane.

Detection

Our databases include more than 100 absorption bands for ozone from 0 to 4033 cm^-1. The following figure shows a typical calculation of the spectral region 2050 to 2060 cm^-1 for a laboratory cell containing ozone at room temperature and pressure. To run calculations customized for your applications, apply now for a Genspect account.

Simulations powered by Genspect. Try our complementary Freetool to generate simulations of ozone absorption, transmission or thermal emission! Subscribe to our premium Genspect service to customize simulations for your applications today!

© genspect.com 2007