My understandings is that E1 and E0 are European emissions standards.IEQc4.4 does not use any emissions standards. It relies on one simple criterion—no added urea formaldehyde (NAUF). I would guess that a lot of E0 and maybe E1 products would comply with IEQc4.4, but I would not rely on these standards to qualify products. The manufacturers must meet a spec of NAUF.