Variations in the OM/OC ratio of urban organic aerosol next to a major roadway

Figures & data

Figure 1. Location of monitoring equipment at Fyfe Elementary School.

Figure 2. Fraction of 2-min AMS data points per hour by wind condition (downwind of freeway, upwind of freeway, parallel to freeway [other directions], or stagnant [wind speed less than 1 m/sec]).

Figure 3. Hourly averaged AMS PM₁ OC and Sunset PM_2.5 OC concentrations (µg/m³), colored by AMS-derived OM/OC ratio.

Figure 4. Average daily OM/OC ratio, OM concentration (µg/m³), temperature (°C), and scalar averaged wind speed (m/sec).

Figure 5. Hourly-averaged OM concentrations (µg/m³) as a function of wind speed, colored by OM/OC ratio.

Figure 6. Average diurnal pattern of small-vehicle volume (counts/hour × 1000), difference in 10-m and 2-m temperature (positive values indicate a stronger ground-level temperature inversion), BC (µg/m³), CO (ppm), wind speed (m/sec), average concentration by hour and PMF factor (µg/m³), OM (µg/m³), and OM/OC ratio at Fyfe during January 5–28, 2008, by hour (LST).

Figure 7. Box plot of OM/OC ratio by hour. Mean values are plotted as a continuous line, and medians as dashes inside each box; boxes represent the interquartile range, and whiskers represent the data range to the 5th and 95th percentiles.

Figure 8. OM/OC ratio and OM concentrations (µg/m³) by time of day (LST).

Figure 9. Box plot of O/C ratios by hour; boxes show the interquartile range, whiskers the 5th and 95th percentiles, dashes the median, and solid line the mean.

Figure 10. Box plot of H/C ratios by hour; boxes show the interquartile range, whiskers the 5th and 95th percentiles, dashes the median, and solid line the mean.

Figure 11. Scatter plot of H/C vs. O/C ratio averaged by hour during all hours of January 2008, colored by average OM concentration; each number indicates the hour (LST).

Figure 12. OM/OC ratio by time of day bin during downwind, upwind, and stagnant (wind speed < 0.5 m/sec) conditions.