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Measured Carbon Monoxide Emission Rates from Stock and Reduced- Emission Prototype Portable Generators



Steven J. Emmerich, Leon Wang, Andrew K. Persily


To better understand and to reduce the occurrence of carbon monoxide fatalities, this paper presents measured CO emission rates from both stock (i.e., without emission reduction technology) and reduced-emission prototype portable generators operating in an enclosed space under real weather conditions. Measurements included CO and O2 concentrations, air change rates determined by tracer gas decay tests, temperature, humidity and electrical loads met by the generators. For two different unmodified generators, it was found that CO emissions ranged from a low of around 500 g/h at near ambient O2 levels to a high of nearly 4000 g/h as O2 approached 17 %. The rates of CO generation and O2 consumption in these unmodified generators were affected by multiple parameters, with the O2 level in the space and the actual electrical output of the generator being two of the most important. Tests performed below 17 % O2 showed a drop off in CO emissions due to poor engine performance. Tests of two modified generators (i.e., with CO emission controls) showed CO emissions reductions of over 90 % depending on the specific emission controls and operating conditions, with no trend toward higher emission rates as O2 levels dropped to 18 %.
Conference Dates
July 7-12, 2014
Conference Location
Hong Kong
Conference Title
Indoor Air 2014


Carbon monoxide, Indoor air quality, Pollutant sources, Portable generators, Residential buildings


Emmerich, S. , Wang, L. and Persily, A. (2014), Measured Carbon Monoxide Emission Rates from Stock and Reduced- Emission Prototype Portable Generators, Indoor Air 2014, Hong Kong, -1, [online], (Accessed April 19, 2024)
Created August 6, 2014, Updated February 19, 2017