He turned off the phone, returned it to the safe. He checked the particulate meter on the wall: 1300 ppm. This for fine particulates, 25 nanometers and smaller. He went out onto the street again, staying in the shade of buildings. Everyone was doing that; no one stood in the sun now. Gray air lay on the town like smoke. It was too hot to have a smell, there was just a scorched sensation, a smell like heat itself, like flame.