TY - JOUR AU - Nasim A Mullen AU - Seema Bhangar AU - Susanne V Hering AU - Nathan M Kreisberg AU - William W Nazaroff BT - Indoor Air LA - eng PY - 2011 SP - 77 EP - 87 T2 - Indoor Air TI - Ultrafine particle concentrations and exposure in six school classrooms in northern California VL - 21 ER -