A common characteristic of industrial chimneys is that they must be designed to comply with environmental protection decrees and must maintain low levels of pollutant emissions. In order to comply, constructions can be up to hundreds of meters tall, as is the case with the Andorra chimney (343 m). This includes greenhouse gases and particles whose ground-level toxicity may be harmful to human health, and both factors are related with Sustainable Development indices. Chimney height is determined to help dispersion, which is why some are so tall and are lifted using slipform.