Ozone (O3) is not emitted directly into the air, but is a photochemical pollutant. Virtually all of it is formed by chemical reactions involving primarily Nitric Oxide (NO), Nitrogen Dioxide (NO2), Non-methane Volatile organic compounds (NMVOCs), Methane (CH4) itself a VOC and Carbon Monoxide (CO). Ordinarily O3 would be kept in check by the titration reaction, whereby excess NO reacts with O3 to form NO2 and O2. However excess NMVOC concentrations have altered this balance allowing NO to produce NO2 without consuming O3 (EEA 2013).
Accumulated ozone exposure values, over a threshold of 40 parts per billion, for crops (AOT40c) increase from Northern Europe towards the South Mediterranean countries. Taken from EEA 2015.
Can causes inflammation in the lungs and bronchia decreasing lung function and aggravating asthma and other lung diseases, leading to premature death (EEA 2013). A 1% increase in O3 emissions has been associated with a 0.1% increase in Asthma admissions to hospital (Janke, 2014). One study has found a link between Maternal exposure to Ozone and the child developing Type 1 diabetes (Malmqvist et al., 2015).
Ozone is powerful, aggressive and reduces plant uptake of CO2, biodiversity and crop yields. Also alters ecosystem structure, impairs reproduction and stunts growth (EEA 2013) (EEA 2014). Increased concentrations of ozone in the air are associated with reductions in Nitrogen fixation (Hewitt et al., 2015).
Globally it is estimated that in the year 2000 total yield losses for the three main staple crops were 3.9–15% for wheat, 8.5–14% for soybean, and 2.2–5.5% for maize as a result of O3 (Avnery et al., 2011).
Ozone is a greenhouse has contributing to warming of the atmosphere (EEA 2013).
A short lived trace gas with an average lifespan of only a few weeks (23 days) in the atmosphere (Edenhofer 2014).