Current World Environment

Bad air is one of the key concerns for most of the urban centres today, and Siliguri is no exceptions to this. In order to assess the air quality of Siliguri, Exceedance factor (EF) method was applied based on the average annual concentration of the pollutants named as; NO₂, SO₂, PM_2.5and PM₁₀and it is found that PM_2.5and PM₁₀are the major pollutants that pose a severe threat for the city. After applying the EF method, it is found that the values of PM_2.5was between moderate to high pollution level and for PM₁₀it falls under high to critical pollution level. On the other hand, the concentration of NO₂and SO₂falls under moderate to low pollution level. Through trend analysis of the various pollutants, it is found that their concentration was varying in nature. In case of PM₁₀, the trend shows high concentration which exceeds national standard; whereas PM_2.5shows its concentration near towards violating the national standard soon if not checked. In contrast, trends of NO₂and SO₂were recorded lower than the national standard. The present situation of ambient air of Siliguri was analyzed based on Air Quality Index which reveals that air quality of the city can be classified into two seasons, i.e. clean air period (from April to October) and polluted period (from November to March). Lastly, the annual trends of PM_2.5and PM₁₀were constructed as they are the major pollutants, and it shows their skewed nature during winter months which results in smog episodes. It unveils how critical the situation of air quality of Siliguri became especially during winter months which seek immediate attention. Thus the study tries to present a vivid scenario about the present air quality of Siliguri, which concludes with some of the suggestions to restrain the air quality.