Air Quality Levels Controlled by City Street Sweeping Efforts
By Doug Marsh, Street Superintendent
The City of Steamboat Springs area had been designated as “non-attainment” in1993 for the National Ambient Air Quality Standards for PM10 (airborne particulate matter with an aerodynamic diameter of 10 microns or less). The Air Pollution Control Division of the Colorado Department of Public Health and Environment and the City of Steamboat Springs developed standards for reducing PM10, thus reaching attainment, with a State Implementation Plan in 1996.
The PM10 standard for Steamboat Springs is to not exceed 150 ug/m3 average within a 24 hour period. If the City violates this requirement more than three (3) times over any three year period, mandatory requirements and fines could be implemented.
The City has not had any violations since 1996, due to the success of a maintenance plan that involves aggressive sweeping operations after each snowstorm throughout the main corridor of town.
Street sanding materials used during the winter months have been found to be the cause of the majority of PM10 violations. With the use of two dustless sweepers, the City has been able to reduce the average PM10 to acceptable levels for the past 7 years.
The maintenance plan calls for the Street Division of Public Works to begin sweeping Lincoln Avenue within 24 hours of a snow event, when the roads are dry. Sweeping begins within four hours and continues through two shifts to accomplish our goals.
The largest source of air pollution in Steamboat Springs is dirt from paved roads, followed by wood burning and dust from unpaved roads. With the City’s aggressive street sweeping program, we are able to clean the streets of sanding materials and fugitive dirt from vehicles throughout the winter months. Dustless, vacuum sweepers that do not require water when sweeping are used so that cleaning the streets can occur during the cold months of winter without losing the effectiveness of quality sweeping.
Hourly PM10 readings are monitored by the Public Works Street Department daily as well as by the Routt County Environmental Health Department. The readings can be viewed to adjust sweeping schedules and assignments. The measuring device for PM10 readings is located on top of the Routt County Courthouse. Filters are weighed and calibrated by the instrument for accurate data.
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