Releases of gases to the atmosphere are an integral and inevitable part of exploration, production and processing operations. The principal (routine) sources are flaring, venting, turbine and engine operation, fluids processing and fugitive losses (for example from pumps, gas driven valves, flanges and pipes). Non-routine and emergency emissions can arise from well testing, emergency flaring and gas venting. Gaseous emissions covered in this report are those considered most relevant from process control as well as regulatory perspectives. They are: carbon dioxide (CO2), methane (CH4), non-methane volatile organic compounds (NMVOC), sulphur dioxide (SO2) and nitrogen oxides (NOX), and separately, greenhouse gases (CO2 + CH4 expressed as CO2 equivalent). Given the wide range of sources of gaseous emissions, it is not practicable (or possible) to measure every single release individually. Industry has, however, developed and updated detailed guidance methodologies to calculate and estimate emissions and losses. Since companies may use a variety of estimation techniques care must be taken when interpreting aggregated data. A number of factors affect the quantity of gases emitted from E&P petroleum industry operations. Consequently, understanding the variations in performance in terms of normalised emission ratios is complex. These factors include: (a) Presence or absence of infrastructure for gas sales; (b); Gas-oil ratio; (c) Reservoir and field characteristics; (d) Use of hydrocarbon recovery techniques; (e) Regulatory and contractual aspects; (f) Age of the fields. The following sub-sections present the overall emission data for the years 2003 to 2009 and regional emission data for 2007 to 2009. In 2009 participating OGP member companies reported emissions of: (a) 302 million tonnes of carbon dioxide (CO2) equivalent to 139 tonnes of carbon dioxide per thousand tonnes of production; (b) 2.4 million tonnes of methane (CH4) equivalent to 1.1 tonnes of methane per thousand tonnes of production; (c) 1.1 million tonnes of non-methane volatile organic compounds (NMVOC) equivalent to 0.5 tonne of NMVOC per thousand tonnes of production; (d) 390 thousand tonnes of sulphur dioxide (SO2) equivalent to 0.2 tonne of SO2 per thousand tones of production; and (e) 843 thousand tonnes of nitrogen oxides (NOX) equivalent to 0.4 tonne of NOX per thousand tones of production. Normalised figures for 2009 emissions (See: Figure 1) are broadly consistent with data published for activities in 2003-2008