Fig. 2From: Variation of major air pollutants in different seasonal conditions in an urban environment in MalaysiaMonthly mean concentrations with smoothing lines indicate trend of  a CO b O3 c NO2 d SO2 e PM10 between 2005 and 2015 and annual trend of f CO g O3 h NO2 i SO2 j PM10 concentration normalised to annual mean of 2005Back to article page