[NOTE: PAHs are a group of chemicals that are formed during the incomplete burning of coal, oil, gas, wood, garbage, or other organic substances ( 22 ).
(PAHs; are; a group of chemicals that are formed during the incomplete burning of coal, oil, gas, wood, garbage, or other organic substances ( 22 )) (a group of chemicals; are formed; T:during the incomplete burning of coal, oil, gas, wood, garbage, or other organic substances)
PAHs a group of chemicals
are are formed
a group of chemicals that are formed during the incomplete burning of coal, oil, gas, wood, garbage, or other organic substances ( 22 )
T:during the incomplete burning of coal, oil, gas, wood, garbage, or other organic substances