GC: n
CT: Tropospheric ozone is also recognised to be a threat to human health (WHO, 2003; Lim et al., 2012) and have a deleterious impact on vegetation (Fowler et al., 2009), and through plant damage it impedes the uptake of carbon into the biosphere (Sitch et al., 2007) as well as impacting built infrastructure (Kumar and Imam, 2013). It is also an important tropospheric greenhouse gas (IPCC, 2007; Stevenson et al., 2013) and is referred to as a short-lived climate pollutant (Shindell et al., 2012).
Ozone-related deaths are estimated to make up about 5–20 % of all those related to air pollution (e.g. Silva et al., 2013; Anenberg et al., 2009; Lim et al., 2012; Brauer et al., 2012). The OECD (OECD, 2012) have stated that “without new policies, by 2050, air pollution is set to become the world’s top environmental cause of premature mortality”. The report goes on to state that “because of their ageing and urbanised populations, OECD countries are likely to have one of the highest premature death rates from ground-level ozone”.
While ozone has a relatively short atmospheric lifetime, typically hours, in polluted urban regions where concentrations of its precursors are high, its lifetime in the free troposphere is of the order of several weeks (Stevenson et al., 2006; Young et al., 2013), sufficiently long for it to be transported over intercontinental scales. Thus in addition to its role as a priority pollutant on an urban scale, it may influence air quality on a hemispheric scale (Akimoto, 2003; HTAP, 2010). There is little doubt that ozone is a multifarious molecule. Recently, Simpson et al. (2014) described ozone as the “persistent menace”. Figure 1 shows some of the key interactions that drive ozone concentrations in the troposphere and some of the feedbacks.
S: ACP – https://bit.ly/2Pzdm45 (last access: 12 December 2018)
N: 1. – tropospheric (adj): Neutral form of the adjective ‘tropospheric’, and this of the noun ‘troposphere’ (1914, from French troposphère, literally “sphere of change”) and the suffix ‘-ic’.
– ozone (n): 1840, from German Ozon, coined in 1840 by German chemist Christian Friedrich Schönbein (1799-1868) from Greek ozon, neuter present participle of ozein “to smell”. Its molecular formula is: O3.
2. Secondary pollutant found in the troposphere.
3. Ozone occurs in two layers of the atmosphere. The layer closest to the Earth’s surface is the troposphere. Here, tropospheric ozone is an air pollutant. The troposphere generally extends to a level about 6 miles up, where it meets the second layer, the stratosphere. The stratosphere or “good” ozone layer extends upward from about 6 to 30 miles and protects life on Earth from the sun’s harmful ultraviolet (UV) rays.
4. Tropospheric ozone is called a “secondary” pollutant because it is produced when two primary pollutants react in sunlight and stagnant air.
5. Tropospheric is not emitted directly into the air, but is created by chemical reactions between oxides of nitrogen (NOx), carbon monoxide (CO) and volatile organic compounds (VOC). To form, ozone needs sunshine to fuel the chemical reaction.
6. In urban areas, high ozone levels usually occur during warm summer months. Typically, ozone levels reach their peak in mid to late afternoon, after exhaust fumes from morning rush hour have had time to react in sunlight. A hot, sunny, still day is the perfect environment for the production of ozone pollution.
7. Tropospheric ozone poses health problems by irritating the nose, throat and lungs and causing chest pain, coughing and nausea. Long-term exposure may result in permanent damage to the lungs. Ozone aggravates respiratory conditions such as allergies, asthma and emphysema and can have pronounced effects, even on healthy individuals who work or play outdoors during hot, sunny summer months when levels of smog are usually at their highest. In addition to its effects on people, ozone is believed to harm forests and agricultural crops and may accelerate the deterioration of rubber tires, paints and dyes in fabrics.
8. Ozone is one of the six common air pollutants identified in the Clean Air Act. EPA calls these “criteria air pollutants” because their levels in outdoor air need to be limited based on health criteria.
9. Cultural Interrelation: We can also mention the movie WALL·E (2008) created by Andrew Stanton.
S: 1. OED – https://bit.ly/2SELz4k ; https://bit.ly/2UJVXJF (last access: 12 December 2018); PubChem – https://bit.ly/2CcaYNd (last access: 12 December 2018). 2. GOVCAN – https://bit.ly/2GdCsWU (last access: 12 December 2018); CIESE – https://bit.ly/2zU08d8 (last access: 12 December 2018). 3. EPA – https://bit.ly/2ca7E4U (last access: 12 December 2018). 4. GOVCAN – https://bit.ly/2GdCsWU (last access: 12 December 2018). 5. EPA – https://bit.ly/2FWpufT (last access: 12 December 2018); SD – https://bit.ly/2QpI19a (last access: 12 December 2018). 6. UCAR – https://bit.ly/2Pz4xqM (last access: 12 December 2018). 7. DESNH – https://bit.ly/2BdLg9k (last access: 12 December 2018). 8. EPA – https://bit.ly/2FWpufT (last access: 12 December 2018). 9. IMDb – https://imdb.to/2NJgBFx (last access: 12 December 2018).
SYN: ground-level ozone, low level ozone, surface ozone, tropospheric O3.
S: TERMIUM PLUS – https://bit.ly/2L8qYTe (last access: 12 December 2018)
CR: air pollution, biosphere, carbon dioxide, carbon monoxide, climate change, contaminant , ecology, environment, global warming, greenhouse effect, greenhouse gas, hydrocarbon, ionosphere, mesopause, mesosphere, methane , nitrogen dioxide, nitrogen oxide, nitrous oxide, ozone layer, pollution, stratosphere, stratospheric ozone.
