awareness=aware + ness。The original meaning of the adjective aware is watchful (attention; vigilant; Beware), vigilant (alert; vigilant; vigilant; Cautious), i.e., "perceived to be on high alert and cognitively active", so the basic meaning of awareness is "to be on alert and on alert".
From the basic meaning, it also leads to "consciously, knowing, knowing", and even more proactive "interest, care".
Because cognition is very abstract, the cognitive state does not need to be counted, so awareness is an uncountable noun, such as.
Example sentence 1】Public awareness of the problem will make politicians take it seriously(Public awareness of the issue will make politicians take it seriously.) [Cambridge Dictionary of Senior Scholars].
Example sentence 2】Environmental awareness has increased dramatically over the past decade(Environmental awareness has increased dramatically over the past decade.) [Cambridge Dictionary of Senior Scholars].
Example sentence 3] there was an almost complete lack of awareness of the issues involved(People are almost completely unaware of the issues involved.) [Oxford Dictionary of Senior Scholars].
Example sentence 4】The group is trying to raise public awareness about homelessness(The organization is working to raise public awareness of homelessness.) [Oxford Dictionary of Senior Scholars].
Example sentence 5] health officials h**e tried to raise awareness about aids(Health ** tries to raise awareness about AIDS) [Longman Dictionary of Contemporary English].
But with modified awareness, it is also possible to use an indefinite article, such as.
Example sentence 6】there is a growing awareness of the seriousness of this disease(There is a growing awareness of the severity of the disease.) A here may be related to there is, which is more compatible with an object with a strong sense of substance; In addition, the awareness of growing modification also strengthens the uniqueness of "one kind of something"; Abstract nouns are more versatile].
Example sentence 7] employees are using a heightened awareness of work flow and demand to cut waste, eliminate cost, and boost qualityEmployees are using a high level of awareness of workflows and needs to reduce waste, eliminate costs, and improve quality. Cambridge Business English Dictionary; Here A emphasizes matching with a particular employee, and Heightened also emphasizes "a certain one"].
Example sentence 8】there seems to be a general awareness that this is not the solution(There seems to be a general awareness that this is not the solution.) [Oxford Dictionary of Senior Scholars].a. Focus on uniqueness].
Example sentence 9] it is an expression of the child's experience at several levels, especially an awareness of a love of nature.(It expresses a child's experience on multiple levels, especially a love of nature.) [a partial "not sure"].
The above usage of uncountable nouns plus indefinite articles is marked as singular noun by some dictionaries. This is because the one awareness in the above example sentence is replaced by two three awarenesses, and the semantics do not make sense.