But he says many parts of the world use too much nitrogen fertilizer, and that harms the environment.

VOA: special.2011.04.05

Henry says a nuclear-free world also means that countries need to work together and create an environment that will help prevent international conflicts.

VOA: standard.2010.08.06

Assistant Director-General for Health Security and Environment at the World Health Organization, Dr.Keiji Fukuda, urged people to practice good hygiene, including washing their hands and covering their mouth when they cough, and if they become sick to stay home.

VOA: standard.2009.04.29