Anchor: The composition of PM can vary considerably from one region to another depending on the sources of particulate emissions in each region.
Entailed: The PM's composition may vary depending on the sources of emissions.
Contradiction: The composition of PM never varies, they are constant.
Contradiction: Three children are rolling around on the floor.
Contradiction: The Mazda RX 7 is pretty fun to drive.
Contradiction: They did not wear helms.
Contradiction: You can find the good life in its coastline, architecture and overall culture.