12-14 September, 2011, Lucknow - Earth Science India
12-14 September, 2011, Lucknow - Earth Science India
12-14 September, 2011, Lucknow - Earth Science India
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National Conference on <strong>Science</strong> of Climate Change and <strong>Earth</strong>’s Sustainability: Issues and Challenges ‘A Scientist-People Partnership’<br />
<strong>12</strong>-<strong>14</strong> <strong>September</strong>, <strong>2011</strong>, <strong>Lucknow</strong><br />
170±104µgm -3 and 136±8µgm -3 , respectively which is far in excess of the 60µgm -3 and<br />
40µgm -3 annual averages permitted by the <strong>India</strong>n National Ambient Air Quality<br />
Standards. Effective Cut Diameter (ECD) for PM 1.0 was also calculated and it was<br />
found 77µgm -3 . The percentage contribution of PM10-2.5, PM 2.5, and PM1.0 to PM 10 were<br />
about 56%, 44% and 25% respectively. Statistical analyses such as paired sample T -<br />
test were performed through SPSS for window software and found that there was no<br />
large variation in ECD for PM 2.5 and PM 10-2.5 . Major cations (NH + 4 , Na + , K + , Ca 2+ and<br />
Mg 2+ ) and anions (F - , Cl - , SO 2- 4 and NO - 3 ) were analyzed along with pH. The average<br />
concentrations of major anions such as SO 2- 4 and NO - 3 were observed to be <strong>12</strong>.93±0.98<br />
and 10.33±1.10gm -3 , respectively. Very high concentrations of SO 2- 4 and NO - 3 were<br />
found in fine mode aerosols. The major sources of SO 2- 4 are due to thermal power<br />
plants which are located in southeast direction and incomplete combustion by vehicle<br />
exhaust. A good correlation among secondary species (NH + , NO - 3 and SO 2- 4 ) suggests<br />
that, most of NH +<br />
4 is in the atmosphere in the form of ammonium sulphate and<br />
ammonium nitrate. During winter, the high concentration of Ca 2+ is observed due to resuspension<br />
of road side dust particles and traffic activities.<br />
DUST PARTICLE MORPHOLOGY: IMPLICATIONS TO<br />
AEROSOL OPTICAL PROPERTIES<br />
S.K. Mishra, Sukhvir Singh, T.K. Mandal and B.C. Arya<br />
National Physical Laboratory, New Delhi 1100<strong>12</strong><br />
email: mishrask@mail.nplindia.ernet.in<br />
Role of atmospheric aerosols (mineral and carbonaceous) in terms of their<br />
radiative effects is still highly uncertain (IPCC, 2007). One of the major sources of this<br />
uncertainty is owing to relatively unknown morphology of dust in the atmosphere. Here<br />
we present morphological parameters (shape, size, Aspect Ratio (ratio of maximum<br />
projection of particle to its width, AR) and Circulatory Parameter (CIR)) of selected<br />
ambient particles collected from NPL, New Delhi during pre-monsoon season, 2010.<br />
The morphological parameters are determinants of the extent of particle nonsphericity.<br />
The Cu-TEM grid and tin sheet were used as collection substrates for atmospheric<br />
particles. The morphological studies were carried out using SEM (Scanning Electron<br />
Microscope) and HRTEM (High Resolution Transmission Electron Microscope)<br />
facilities at NPL. For some of the particles, aggregates of black carbon spherules were<br />
found to be adhered on their surfaces. A range of AR was found to be from 1.2 to 2.6<br />
whereas the conventional value of AR of atmospheric particle taken as 1.5 (Okada et<br />
al., 2001). The shape distribution has been generated using CIR parameter with limited<br />
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