Ozone is a colorless gas found in different parts of the atmosphere. In the upper atmosphere, Ozone helps to protect the earth from the sun’s harmful ultraviolet rays. But the ozone found near the ground in the troposphere is harmful to human health as well to the environment. The ground-level ozone is mostly produced, when Nitrogen Oxides (N2O) and volatile organic compounds (VOCs) react through photochemical processes in sunlight. Besides natural emission, the main sources of Ozone are power plants, motor vehicle exhaust, industrial facilities and chemical solvents. These emissions pollute air and form a major ingredient in the creation of smog. Humans also contribute to the formation of ground-level ozone primarily through burning fossil fuels in the transportation, industrial and electricity generation sectors. Almost all the countries in Asia agree to protect the ozone layer by taking measures to control the production and consumption of substances that deplete it. Yet as the interactive map indicates, the impact of Ozone pollution is widespread in Asia. From China’s smog-hit cities, to India’s changing rainfall patterns, to losses of crop yields in Japan and Pakistan, to premature deaths in many other countries - Ozone poses a threat to human life and live-hood. High ozone levels are commonly responsible for an increasing number of asthma attacks and other respiratory health diseases, especially when children and the elderly are concerned.
Nitrous oxide (N2O), an oxide of nitrogen, or laughing gas as it is commonly known, is a major greenhouse gas and air pollutant. According to the United States Environmental Protection Agency (EPA), every N2O molecule has 310 times the capacity to trap heat in the atmosphere than a carbon dioxide molecule. The atmospheric levels of this gas have risen by more than 15% since 1750. What makes it even more severe, is the fact that N2O emissions are considered to be the single most important ozone-depleting substances to destroy stratospheric ozone, which in turn protects the earth from harmful ultraviolet rays. The trend is expected to continue for at least the next 100 years. According to 2006 EPA data, while tropical soils and oceans release 70% of N2O into the atmosphere, human activity is thought to account for 30% of such emissions, wherein about 20% is accounted for by industrial sources (production of nylon is a notable source) and burning of fossil fuel in internal combustion engines, factories, power plants and even rockets. But a 2008 study by Nobel Laureate Paul Crutzen seeks to propound that the contribution of agricultural nitrate fertilizers to the amounts of N2O release has been seriously underestimated. Crutzen’s work was underlined in 2012 by researchers at the University of California, Berkeley, where it was found that increased fertilizer use over the past 50 years was indeed responsible for the dramatic rise in atmospheric N2O contributing to changes in global climate. It was explained that nitrogen-based fertilisers stimulate microbes in the soil to convert nitrogen to N2O at much faster rates than normal. Like in other parts of the world, the use of this gas in Asia, as shown by the graph, has increased progressively. China leads the Asian countries in N2O emissions, followed by India and Indonesia - underlining the correlation between economic growth, burgeoning population and increasing production of N2O. The graph illustrates the comparative N2O levels in some Asian countries. The figures are in thousand metric tons of Carbon Dioxide Equivalent (CO2e) which refers to the amount of different greenhouse gases in terms of the amount of CO2 that would create the same amount of warming.
Besides nitrogen-based fertilisers, one of the prominent causes of rising nitrous oxide (N2O) emission levels is fossil fuel burning, which undoubtedly points a finger at the increasing use of automobiles by a burgeoning global population which, if current trends are an indicator, will only increase in the times to come. According to the World Bank, emissions from automobiles contribute to more than one-third of the N2O released into the atmosphere. Nitrogen oxides are formed in the combustion process by oxidation of nitrogen (from the atmosphere and fuel) to nitrogen oxide and N2O. When oil in vehicles burn, they spew out previously fixed nitrogen from earth’s geological formations unto the atmosphere in forms that include N2O. The spewing is more so in the case of high-temperature combustion engines. More amounts of N2O in the atmosphere would mean overall greenhouse warming, depletion and thinning of the ozone layer, formation of photochemical (brown) smog and occurrence of acid rain. Predictive studies say that the production of N2O from fossil fuels like oil and coal would more than double in the next 25 years. The increase will be particular in the developing nations like China, India, Indonesia, which are riding the tiger of growth and yet straddled by rising populations. The International Energy Agency has predicted that the number of vehicles on the road will double by 2035, when there will be a whopping 1.7 billion cars or 310 cars per 1000 people - and one billion of those will be in Asia. While plans to cut back on these emissions are easier said than done, improvements in the efficiency of fuel combustion as well as in the interception of airborne byproducts of combustion will be a good start to a process of trying to rein in the growing monster. The graph shows numbers of motor vehicles per 1000 people in Asian countries.