Cereal waste burning pollution observed in the town of Vitoria (northern Spain)

Agricultural waste burning is a widespread practice throughout the world but there is little information about its pollutant impact. This paper deals with a preliminary study of the pollution observed in Vitoria (Northern Spain) caused by cereal waste burning. The mean hourly flux of pollutants produced by cereal waste burning fires can reach values of 1.4 kt of CO2, 13 t of TPM and 3 t of NOx in the area around Vitoria. Measurements obtained in the area of emission and inside fire plumes show high ratios (NO2/NOx) indicating that nitrogen oxides emitted by the source undergo a rapid transformation in the same area of emission. Results relating to aerosol composition collected in Vitoria during burning periods show an increase in the concentration of K+, NO3− and Cl− ions, that are inter-correlated. The modification of the ionic composition of aerosols also affects the chemistry of the rain collected in Vitoria. During the burning period, it is particularly noticeable that anthropogenic pollution (usually identifiable by the correlation between SO42− and NO3− concentrations) disappears, indicating the existence of an independent source of NO3− not linked to the SO42− source. Similar results were deduced studying BAPMON data collected in Spain during cereal waste burning. Finally, we note that ozone concentration measured at Vitoria is not affected by the pollution generated by the burning fires.