horses grazing near Haystack Mountain 

Air Quality Monitoring

Public Health Monitors Air Quality in Boulder County

Boulder County Public Health (BCPH), monitors forty air toxics at five locations throughout the county, thanks to a grant from the U.S. Environmental Protection Agency (EPA). The last monitoring study in Boulder County, conducted in 1996, provided monitoring of just three air toxins at one Denver and two Boulder County locations.

Boulder County Air Toxics Study

The purpose of the study was to collect data concerning air toxics concentrations in Boulder County. The study found that local sources appear to impact each site differently and at varying magnitudes.

Air Quality Varies Throughout Boulder County

Monitoring at the downtown Boulder site, which is in close proximity to vehicular traffic, showed elevated concentrations of air toxics common to vehicle exhaust. The Longmont site was located near oil and gas exploration activities and showed elevated concentrations of n-butane and n-pentane, two evaporative VOCs found in gasoline vapor and natural gas condensate. The Lyons site was located near vehicular traffic, a cement plant, and oil and gas exploration activities and did not appear to be strongly influenced by one particular source.

Boulder County Is a Mix of Urban and Rural

Because Boulder County sits at the point where the heavily urbanized City of Denver and the rural wilderness of the Rocky Mountains meet, a complex air quality environment is created that can intensify organic trace gases. This study helps us better understand and assess local air quality and develop management strategies.


The study is in collaboration with researchers at the Mechanical Engineering Department and an analytical laboratory at INSTAAR (Institute of Arctic and Alpine Research) at CU Boulder. Sample collection will be performed over 24 hours every sixth day. Ozone will be monitored at all stations continuously, with one-hour time resolution. Analysis will also look for “indicator” pollutants that will help us roughly estimate the sources of pollution.

The study is also intended to evaluate the air quality impacts of industrial activities, oil and gas exploration, and vehicle emissions. It will define concentrations of local air toxics and build on the findings of previous studies.

“From a human health standpoint, this study will give us the data to address community concerns and support evaluations of health effects,” said Milmoe. Specifically, BCPH will provide information to better evaluate the findings of two health consultations conducted by the Agency for Toxic Substances and Disease Registry.

The forty organic gasses will be monitored over a one-year period. The proposed locations for monitoring include Niwot Ridge, the city of Boulder, the city of Longmont, the city of Lyons, and South Boulder Creek. Each location has been specifically selected to provide information about particular environmental factors such as traffic, agricultural burning, oil and gas development, and airflow.

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Air Quality Program

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