Globalization and liberalization polices of the government of India have increased the number of
road vehicles nearly 92.6% from 1980-81 to 2003-2004. Therefore to know whether there is effect of
increase of industrialization in the urban areas like Pune (18° 32′N, 73° 51′E); Mumbai (18° 55' N,
72° 54' E) and at rural station like Ramanandnagar (17° 4′ N, 74° 25′ E); pollution index is measured.
Pollution index which is ratio of average positive to negative small air ion ratio is plotted for week
days and week end. At the rural station like Ramanandnagar Monday to Saturday are working days,
while Sunday is holiday. It is observed that ratio of average positive to negative small ion ratio is
maximum for all time periods during the week day as compared to week end. The data have been
collected during the period from first 1 June 2007 to 31 May 2008; the period under analysis involves
8,040 hours shows that the peak of the positive to negative small air ion ratio is observed in winter,
and dip is observed in post-monsoon season. As Ramanandnagar is surrounded by vegetation area,
therefore due to plant transpiration of Radon and Thoron small air ion maximum are observed at
noon time rather than night time. During the week end positive small air ion count is low as
compared to week days. While during week end negative small air ion count is very high as
compared to week days, which is observed in all the seasons. Post-monsoon is the transition period
during which few thunder storms are observed. Due to these thunder storms additional amount
negative ion are introduced and positively charged aerosols are cleared from the atmosphere.
Therefore in the post-monsoon negative small air ion count is high as compared to all other seasons.
Such type of diurnal variation of small air ion detected at rural station Ramanandnagar has never
been observed elsewhere.
Diurnal and Seasonal Air Ion Variability at Rural Station Ramanandnagar (17°2′N, 74°E), India