On April 28th when the air quality in Doi Saket was in the purple very unhealthy zone, 10 teenage boys sat on mats spread on the floor at the House of Hope Orphanage and watched intensely as Sippawut ‘Knot’ Chaengsri, sitting on the opposite side of a low table, assembled an air purifier from locally purchased components. Knot began this training by explaining the dangers of PM 2.5 to their