Based on the air quality data, the high levels today are mainly due to a combination of combustion emissions (smoke) and road dust. The 24 hour PM_2.5 rolling average was 16 µg/m³ at the Plaza 400 downtown site at 4:00 pm and 13 µg/m³ at College Heights. The 24 hour PM₁₀ rolling average was 53 µg/m³ at the Plaza 400 downtown, 38 µg/m³ at BCR and 31 µg/m³ at College Heights. This Air Quality Advisory is expected to be in effect until further notice, with an update to be provided tomorrow morning at 9:30 am.