Use timestamp column in where clause

[nikhilv-quantela]

Unable to use timestamp, for example:
"what is minimum monoxide in pollution_data when time_stamp equals 2017-03-23"

my timestamp has both time and date.

Also tried using:
"what is minimum monoxide in pollution_data when extract(month from time_stamp) equals 3"

datatypes are:-
time_stamp timestamp with time zone,
monoxide double precision,

P.S.: not using real names of columns and table for privacy reasons