The indicators of NO emission from combustion of selected types and forms of a biomass are shown in Table 3.
Under the test conditions, values of NO emission indicators converted into the reference of 10% O2 in exhaust gas,
varied. The highest values of this ratio were recorded during the combustion of cake pellets at the maximum rate of
air flowing to the boiler. Under the same combustion conditions, lower emission values were found for pellets made
of rape straw. Accordingly, the average values for these fuels were 871 and 604 mg•m-3 at 10% O2. The lowest
values (174 mg•m-3 at 10% O2, on average) were recorded for birch pellets also at the air flow rate at a level of 2.5
m•s-1 (Table 3). Based on the variance analysis of values specified for NO emission, significant differences between
the mean values in each group of raw materials were observed, and Tukey test indicated a single homogeneous a-a
group for the NO emission indicators (p=0.999729) (Table 3).