It was over 50°C (130°F) outside when Mark Lyles slipped on his flak jacket,
helmet and goggles, grabbed his N95 dust mask, and climbed aboard a Blackhawk
helicopter at the US Central Command Zone in Iraq four years ago. The prop blades
kicked up a fine grit that would hang in the air for days. Lyles knew that these
particles, finer than talcum powder and teeming with microbes, would become lodged
deep within the lungs of the soldiers stationed there. Part of his job as a Navy
captain and cell biologist was to sample Iraq's soil on the ground and in the air;
he presented some surprising findings from that analysis this September at the 10th
annual Inhaled Particles conference in Sheffield, UK. "It's constantly there," Lyles
says of the dust, "sometimes it's bad and sometimes it's worse."
