Abstract: The occurrence of high nocturnal surface ozone over a tropical urban area (23̊ 32′16.99″ N and 87̊ 17′ 38.95″ E) is analyzed in this paper. Five incidences of nocturnal ozone maxima are recorded during the observational span of two years (June, 2013 to May, 2015). The maximum and minimum values of the surface ozone during these five occasions are 337.630 μg/m3 and 13.034 μg/m3 respectively. HYSPLIT backward trajectory analyses and wind rose diagrams support the horizontal transport of ozone from distant polluted places. Planetary boundary layer characteristics, concentration of precursor (NO2) and meteorology are found to play important role in the horizontal and vertical transport of surface ozone during nighttime.
Abstract: Several studies have shown the association between
ambient particulate matter (PM) and adverse health effects and
climate change, thus highlighting the need to limit the anthropogenic
sources of PM. PM Exposure is commonly monitored as mass
concentration of PM10 (particle aerodynamic diameter < 10μm) or
PM2.5 (particle aerodynamic diameter < 2.5μm), although increasing
toxicity with decreasing aerodynamic diameter has been reported due
to increased surface area and enhanced chemical reactivity with other
species. Additionally, the light scattering properties of PM increases
with decreasing size. Hence, it is important to study the chemical
characterization of finer fraction of the particulate matter and to
identify their sources so that they can be controlled appropriately to a
large extent at the sources before reaching to the receptors.