Dear Netters!
It is a well-known rule not to use the Indefinite Article with uncountable nouns.
E.g. 'I need help', 'I can't deal with anger', 'There was panic in his eyes.' However, the Indefinite Article can be used when you point out a certain aspect of the noun used. This aspect can be shown through a descriptive or evaluative adjective. This is called an aspective funtion of the Indefinite Anger, as if there were many different kinds of 'anger' or 'help' or 'panic'
E.g.: 'An overwhelming anger churned his mind'. ' There was a killing panic in his eyes'.
So, in the sentence below, I recommend using the Indefinite Article with the phrase 'ill atmosphere', i.e. it should be 'an ill atmosphere'
'But still I don't approve of irregular and non-committal relations. I think they create an ill atmosphere and set a bad example for children.'
On the other, this usage is often limited to such descriptive or evaluative contexts
