Variability of Ozone and Related Trace Gases Over India
Shyam Lal, S.K. Peshin, M. Naja and S. Venkataramani
The earth’s atmosphere contains a variety of trace gases in addition to the major gases like nitrogen, oxygen, and argon. Most of the trace gases are of natural and anthropogenic origin. They contribute significantly to the air quality and climate change apart from their chemical roles. Ozone (O3) is of mostly natural origin and protects life on the earth by absorbing the biologically active UV-B (280-310 nm) radiation in the middle atmosphere (20-30 km range). However, man-made CFCs, transported to the stratospheric altitudes from surface, destroy the precious ozone layer thereby depriving earth of its natural protection. This effect is highly pronounced in the Antarctic and to a lesser extent in the Arctic regions. However, in the troposphere (ground to about 18 km) ozone acts as a greenhouse gas and is referred to as a short-lived climate pollutant. Ozone, in the lower atmosphere, is produced from the ozone precursors, namely CO and hydrocarbons in the presence of oxides of nitrogen. Thus, ozone is greatly affected by the pollution levels. It is found to increase in several polluted regions and their outflow affecting the regions away from the major pollutant regions. Global climate change is real, and its effects are being observed world over as well as in India. The climate change effects are clearly reflected over India in the changes in surface air temperature, melting of the Himalayan glaciers, unusual seasonal climate change patterns, frequent occurrence
S. Lal (H) • S. Venkataramani
India Meteorological Department (IMD), Earth System Science Organization, New Delhi, India
Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital, India © Springer Science+Business Media Singapore 2017
M.N. Rajeevan and S. Nayak (eds.), Observed Climate Variability and Change Over the Indian Region, Springer Geology, DOI 10.1007/978-981-10-2531-0_14
of extreme weather events, etc. (Kothawale and Kumar 2005; Kulkarni et al. 2007; Mallik and Lal 2011, Chaps. 3 and 4 of this book).
Tropospheric ozone is also recognized as a threat to human health and vegetation. Ozone-related deaths are estimated to make up about 5-20 % of all those related to air pollution, and India has been shown to be among top ten polluted countries (Lelieveld et al. 2013). Its deleterious impact on vegetation through plant damage impedes the uptake of carbon into the biosphere (Sitch et al. 2007). Hence, ozone plays key roles in atmospheric chemistry, radiation balance, and air quality, including human health. This chapter presents some of the studies related to ozone and associated trace gases.