当人们吸入PM2.5时，细小的固体和液体灰尘、污垢、有机化学物质和金属液滴可以深入肺部，甚至进入到血液当中。
When people inhale PM2.5, microscopic solids and liquid droplets of dust, dirt, organic chemicals, and metals can travel deep into the lungs and even enter the bloodstream.