3.2 Morphological analysis of PM1
The PTFE filter paper used for the collection of PM1 samples has been used for the morphological study with the help of Scanning Electron Microscope (SEM). SEM image gives specific source of PM1 whether it is due to primary formation or secondary formation Mirjana et al 2006. As suggested by Atar Singh et al 2014, Energy Dispersive X-ray spectroscopy (EDAX) which gives the elemental composition of PM1 is also used in the present study.
The SEM image morphology for the location BAS Fig. 3.a shows that the particulates are spherical and irregular in shape with a mix of smooth and rough surface area. The elemental composition in PM1 is expressed in weight% which indicates the relative concentration of the element in the sample. The elemental composition is Carbon, with 30.72 weight%, and Oxygen with 1.21 weight% respectively with small trace of Phosphorus.
The SEM image morphology for the location HOS Fig. 3.b. shows that particulates are spherical and irregular in shape with smooth and rough surface area and the elemental composition sampling site was Carbon, Oxygen with 29.89 weight % and 1.65 weight % respectively with small traces of Phosphorus.
The morphology of collected sample at location HOS during Diwali festival (5–6 November 2018) shows clearly that particulates have different morphologies. On 5th November 2018, the particulates were spherical and irregular in shape with smooth and rough surface area Fig. 4.a with elemental composition on the previous day of Diwali was Carbon 58.64 weight%, Oxygen 28.77 weight %, Nitrogen 11.66 weight% and small traces of sulphur. Whereas on 6th November 2018, along with spherical and irregular shape, the particulates are observed to have plate like, rod like structures with smooth and rough surface area Fig. 4.b. with elemental composition of Carbon 50.30 weight%, Oxygen 41.89 weight%, Nitrogen 5.44 weight% and small traces of Aluminium, sulphur and potassium.
The morphology of collected sample in location BAS in december month Fig. 5. a. shows that collected Particulate during sampling were irregular in shape and rough surface area and some of them were biological particles Mirjana et. al2006 and the elemental composition was found to be Carbon 46.81 weight%, Nitrogen 17.88 weight%, Oxygen 34.25 weight% and small traces of sulphur.
The morphology collected sample at HOS location in december Fig. 5.b. shows spherical shaped particulates with smooth surface and rough surface area with rod shaped particulates which may be Bacillus pumilus as observed in Flavien Pillet et al 2006  and the elemental composition in was Carbon 56.17 weight%, Nitrogen 12.09 weight%, Oxygen 30.92 weight% and small traces of Potassium and Sulphur.
The samplings were carried out in December and January month respectively at DOM location and on both days sampling the particulates are irregular in shape with rough surface area Fig. 6. a.-6. b. The elemental composition during these two sampling were Carbon 56.85 weight%, Nitrogen 15.31 weight%, Oxygen 26.98 weight% and with small traces of Sulphur and Potassium and Carbon 52.36 weight%, Nitrogen 19.81 weight%, Oxygen 27 weight% and with small traces of Sulphur and Potassium respectively.
In the month of January two samplings were carried at BAS location and morphological analysis of one sample shows that particulates were irregular in shape and rough surface area Fig. 7.a. and the elemental composition was Carbon 50.93 weight%, Nitrogen 13.32 weight%, Oxygen 34.59 weight% and small traces of Sulphur and Potassium. Other sample was used to analysis the presence of microorganism as the size of bacteria or virus varies from 100 nm to few micrometre size Ya-fen Wang et al 2010. The sample filter paper was placed on LB-Agar solution in an autoclaved plate which acts like a growth medium for bacteria or virus and same was stored in incubator overnight at a temperature of 37 °C and SEM of the same filter paper was carried out. The morphology of collected sample shows that particulates were completely rod-shaped particles which confirms that presence of bacteria Bacillus Fig. 7.b. Christine G et al 2016 and the elemental composition was found to be Carbon 37.30 weight %, Nitrogen 2.04 weight %, Oxygen 7.54 weight % and small traces of Phosphorus and Sulphur
One sampling was carried out at BAS location in February and two sampling were carried out at DOM location in March and April were again used to study the presence of microorganism in the collected filter paper with SEM image technique and the same confirms the presence of microorganism with rod shaped morphology that is bacteria Bacillus Fig. 8.a-8.c and some particulates have cubical in shape with smooth surface area which may Sodium Chloride and the elemental composition at BAS location is found to be Carbon 44.29 weight%, Nitrogen 4.51 weight%, Oxygen 11.61 weight%, Sodium 7.52 weight% and small traces of Silicon, Phosphorus, Sulphur and the elemental composition DOM location March and April is Carbon 36.63 weight%, Nitrogen 2.10 weight%, Oxygen 6.50 weight%, Sodium 5.32 weight% and Chlorine 3.89 weight% and Carbon 47.31 weight%, Oxygen 25.05 weight%, Nitrogen 10.32 weight%, Sodium 3.12 weight% and small traces of Silicon, Phosphorus, Sulphur, Chlorine and Calcium respectively.
The morphology of sampling collected at DOM location in the month of May particulates in ambient air were spherical, irregular in shape with rough and smooth surface area Fig. 8.d. The elemental composition was found to be Carbon 31.31 weight%, Oxygen 2.62 weight% and small traces of Sulphur.
The morphology of sampling at DOM location in May and June were carried out shows that particulates are regular and irregular in shape with smooth and rough surface area Fig. 9.a-9. b and elemental composition Carbon 29.37 weight%, Oxygen 2.68 weight% and small traces of Sulphur and Carbon 33.91 weight%, Oxygen 3.63 weight% and small traces of Nitrogen, Sodium and Sulphur.
The morphology of sampling at DCH location also shows the Particulates are regular and irregular in shape with smooth and rough surface area Fig. 9. c-9. d. which is in the month of June and July and the elemental composition Carbon 29.61 weight%, Oxygen 1.06 weight% and small traces of Aluminium and Sulphur and Carbon 29.33 weight%, Oxygen 1.50 weight% and small traces of Sulphur.
The particulate matter morphology in the study period was mainly found to be spherical shape with smooth surface area shows that PM1 source ambient air is mainly anthropogenic activities such as vehicular traffic, industrial activities, bio mass burning and irregular in shape with rough surface area identifies that source of PM1 is natural activities such as dust particles, resuspension of road dust, wind and the presence of bacteria in ambient air is also confirmed.