Photo: referendum in Ukraine in December 1991.

  It was around 24 years ago in Amsterdam. To be precise the 2^nd of December, 1991. At the same time that Mikhail Gorbachev was thinking about resigning as President of the Union of Soviet Socialist Republics, a group of enthusiasts met to discuss about the first standard about odour concentration measurement. Today, 33 countries of Europe are using this standard to measure odour concentration. But that was not easy a few years back.

   To start with this history we should go back to 1984.

   The 22^nd of June 2015, a new version of the CALPUFF software has been released. The Version 7 of the CALPUFF modeling system contains many new features. The model updates introduce new source types including roadways and flare modeling. The new pre-processor SURFGEN which can process sub-hourly ASOS data and the post-processors CALRANK, CALAVE and CALMAX are also now available.

   This version 7 includes all the new features introduced in Version 6 (which is now being deprecated), such as the ISORROPIA (now updated to v2.2) inorganic gas-particle equilibrium model, aqueous phase chemistry and an anthropogenic secondary organic aerosol (SOA) module based on the CMAQ/MADRID model; options to use sub-hourly time steps for both meteorological and emissions data, nested grid capabilities; an option in CALPOST to compute daily peak one-hour concentration values consistent with the new U.S. 1-hour SO2 and NO2 standards.