An emissions output of an engine, such as a diesel generator, may be determined from the load on the engine and an exhaust volume from the engine. Chemicals such as nitrogen oxide (NOx) may be calculated for a measured load on the engine. The calculation may include determining an air flow in the engine from air pressure measurements and turbo compressor speed measurements. The calculation may also include determining a gas flow into the engine by deriving fuel flow from known test results. The calculated emissions output may be used to ensure compliance of an engine with environmental regulations. A remote monitoring program may generate alerts when the engine fails to comply with environmental regulations.