Abstract We address some phenomena about the interaction between lower semicontinuous submeasures on $${\mathbb {N}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>N</mml:mi> </mml:math> and $$F_{\sigma }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>F</mml:mi> <mml:mi>σ</mml:mi> </mml:msub> </mml:math> ideals. We analyze the pathology degree of a submeasure and present a method to construct pathological $$F_{\sigma }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>F</mml:mi> <mml:mi>σ</mml:mi> </mml:msub> </mml:math> ideals. We give a partial answers to the question of whether every nonpathological tall $$F_{\sigma }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>F</mml:mi> <mml:mi>σ</mml:mi> </mml:msub> </mml:math> ideal is Katětov above the random ideal or at least has a Borel selector. Finally, we show a representation of nonpathological $$F_{\sigma }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>F</mml:mi> <mml:mi>σ</mml:mi> </mml:msub> </mml:math> ideals using sequences in Banach spaces.