The Atmospheric Chemistry Laboratory (ACL) of the National Observatory of Athens (NOA) was founded in 1996 by the Institute for Environmental Research and Sustainable Development (IERSD), one of NOA’s three institutes. ACL/NOA is located at IERSD’s premises in P. Penteli. In 2005, the Laboratory upgraded its existing infrastructure, for the provision of chemical analyses and air pollutants measurements services, with emphasis on hazardous for public health chemical compounds and species that are harmful to the environment. The immediate objective of ACL/NOA is the provision of high quality accredited services for measuring atmospheric and other pollutants, in order to meet the demands of Greek society, state and private bodies, for sustainable economic and technological development, coupled with environmental and public health protection. In parallel to the provision of accredited services, ACL/NOA participates in national and international research projects, conducting both basic and applied edge research, among others within the fields of Atmospheric Chemistry and Physics and Air Quality. The laboratory equipment includes a variety of analytical instruments regarding to chromatographic and spectroscopic techniques, as well as auxiliary equipment and sampling apparatus. Provide measurements of particulate matter (PM) via gravimetric mass concentration determination and analyses of passive samplers for ozone and nitrogen dioxide level. Additionally, methods for the determination of atmospheric concentration of benzene, metals and polycyclic aromatic hydrocarbons are under development. Part of these methods is accredited by the Hellenic Accreditation System S.A. according to ΕLΟΤ EN ISO/IEC 17025:2005.