How much smoke was in the air when the 9-11 twin towers crash happened?

On September 11, 2001, when the Twin Towers were attacked, the air quality in lower Manhattan was severely affected by smoke and debris from the collapses. The immediate aftermath produced a massive cloud of dust and smoke that contained harmful particulates and toxins. Although specific measurements of smoke density vary, it was reported that visibility was drastically reduced in the area due to the thick smoke and dust, creating hazardous conditions for both first responders and residents.