COMPARATIVE STUDY OF AIR POLLUTION LEVELS IN RURAL AREA AND KIGALI CITY BASED ON AIR QUALITY INDEX.

Abstract

Considering that the increase in road traffic, domestic fuel burning and industry is claimed to worsen the air quality in Kigali city, the comparison of air pollution levels between rural area and Kigali city was thought about to find out their extent in air pollution relative to one another. The main objective of this study is to compare the air pollution levels in rural area and Kigali City based on Air Quality Index. It was customary to present air quality findings as time series plots, statistical analyses and other scientific techniques to analyse data which were not sufficient for a common person or the general public to get the clear picture of how good or bad the air is in a particular place. This has resulted in low awareness about air pollution problem and hence a less involvement of people in air quality improvement. This study has incorporated the concept of Air Quality Index in showing air pollution levels to overcome such difficulties. It has been considered air quality data for three months (November 2017, December 2017 and January 2018) collected at two stations from rural area (Gasaka and Kawangire) and two stations from Kigali city (Gitega and Nyabugogo) by using AQMesh monitors, and the other relevant information used in calculating the Air Quality Index was derived from internet. The key air pollutants to which analysis was made are PM2.5, SO2, NO, NO2, CO and O3 and the difference identified between rural area and Kigali city is based on the highest SO2, NO and NO2 concentrations observed at Nyabugogo and Gitega locations. Though there are considerable vehicle emissions at Nyabugogo location, the measured air pollutant concentrations were at moderate levels as the calculated Air Quality Index at this location remained below 100 during the period of three months (91 days) and hence the air quality was acceptable. The higher O3 and CO concentrations measured at Gasaka station affected the air quality of that location such that within 91 days, the air quality was acceptable in 67 days only. The air quality at Gitega location was acceptable in 38 days only out of 91 days and this is attributed to the highest level of O3 concentrations characterized that place. The last location characterized by poor air quality is Kawangire where the highest PM2.5 concentrations aggravated the air quality in such a way that within 91 days, the air quality was acceptable in 36 days only.