Air pollution is a pollution of the indoor environment by any chemical, physical or biological agents that change the atmosphere's natural characteristics. Household burning tools, motor vehicles, industrial solutions, and forest fires are the common origin of air pollution. Indoor air pollutants are removed for household tasks such as cooking, cleaning, heating, cosmetics, and wall paint. Indoor air pollutants are ten to twenty times higher than health guidelines for typical urban outdoor concentrations. The utilization of solid fuels for cooking and baking is probably the most significant source of indoor air pollution on a global scale—almost half the world resume cooking with solid fuels such as wood, agricultural wastes, and coal. When used in a simple cooking furnace, these fuels release many toxic pollutants. These pollutants, called solid-fuel smoke, include respirable particles, carbon monoxide, oxides of nitrogen and sulfur, benzene, formaldehyde, 1,3-butadiene, and polyaromatic such as benzopyrene compounds.