Abstract
Diurnal variations of surface ozone and NOx (oxides of nitrogen) at Kannur University Campus (12.3N, 75.4E), a rural location and at Kannur Town, an urban location in Kannur (11.9N, 75.3E), a tropical coastal site in the state of India have been studied during winter months of 2009 and 2010. Being an industrially weak area, the study has the uniqueness to reveal the surface ozone production from its prominent precursor NOx at this site lying along the coastal belt of the Arabian Sea. The maximum value of surface ozone has been observed during day time and minimum during night at two locations. The rate of production and loss of surface ozone is higher at a rural location than an urban location in the same region. This highlights the substantial difference in the ozone chemistry over these two locations.
Highlights
The composition of the Earth's atmosphere has been changed by human activity and some of these changes are harmful to human health, crops and ecosystems
This study is the first attempt in this region which is lying along the coastal belt of the Arabian Sea to explore the production of surface ozone from its prominent precursor NOx during winter months
The variability of surface ozone and its precursor NOx have been monitored at Kannur University Campus (KUC) and Kannur Town (KT) during winter months of 2009 and 2010
Summary
The composition of the Earth's atmosphere has been changed by human activity and some of these changes are harmful to human health, crops and ecosystems. There are many other gases which are in low quantities but play an important role in its chemistry and radiation budget These are divided into two different levels of concentrations, viz minor constituents and trace gases. The production of surface ozone plays a crucial role in the chemistry of the earth’s atmosphere, though it is a minor constituent in terms of its abundance (Naja et al, 2004; Subbaraya & Shyam Lal, 1998). Surface ozone does not have direct natural sources, but it is produced in the atmosphere mainly due to its precursors emitted by the increased human activities (Purkait et al, 2009). Surface ozone is mainly produced by the photo dissociation of NO2 in the day time as NO2 + hν (λ < 410 nm) Î NO + O (3P) ----- (R1)
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