Measurement of sulphur dioxide (SO_{2) and nitrogen dioxide (NO2) during winter over a period of three years at Kaikhali (22.022 degree N and 88.614 degree E) in Sundarbans}

Measurements of the two criteria air pollutants sulphur dioxide (SO2) and nitrogen-dioxide (NO2) capable of adversely affecting areas of rich biodiversity were made at a far off coastal remote area Kaikhali (22.022°N and 88.614°E) in one of the world’s largest mangrove ecosystems – ‘The Sundarbans’ from 2004–2007. The objectives of the measurements were to determine the trend in occurrence of these two in the winter period and also to determine their probable sources. The average ranges of SO2 and NO2 concentrations during the winter months over these three years have been found to be (0.34–3.02) ppb and (2.75–21.71) ppb respectively. As, during the study period, no standards for these pollutants were available for such an ecologically sensitive area, their average concentrations for the last year of study have been compared with that for the nearest metropolis Kolkata which indeed confirmed relatively high values of SO2 and NO2 at Kaikhali.