Table 1.
Summary meteorology, daily average pollen counts, PM2.5 tracer concentrations, and background sampling periods in May 2019.
| Sampling perioda | Description of meteorologyb | Temperature range (°C) | Cumulative rainfall (mm) | Daily average pollen counts (grains m−3) | PM2.5 fructose concentration (ng m−3) | PM2.5 mannitol concentration (ng m−3) | PM2.5 endotoxin concentration (EU m−3) |
|---|---|---|---|---|---|---|---|
| May 7 (background) | Early morning light rain on May 8 | 7.2–16.6 | 3.8 | 611 | 0.31 | 0.71 | 0.012 |
| May 8 | Multiple rain events with moderate to heavy rainfall, and an afternoon thunderstorm | 6.8–20.5 | 16.8 | 185 | 0.67 | 5.55 | 0.120 |
| May 15 (background) | No rain events | 10.7–25.0 | 0 | 145 | 1.10 | 6.18 | 0.013 |
| May 16 | Multiple rain events with light to heavy rain, thunderstorm around mid- night and a severe thunderstorm at night | 17.5–33.1 | 18.2 | 449 | 2.17 | 11.8 | 0.183 |
| May 17 | Continued rain event from prior sampling period and light rain in the afternoon | 9.7–20.8 | 6.4 | 159 | 1.15 | 7.70 | 0.152 |
| May 18 | Multiple rain events with moderate to heavy rain and several thunderstorms | 12.5–25.3 | 20.6 | 117 | 5.70 | 25.0 | 0.213 |
| May 23 (background) | Early morning light rain on May 24 | 13.4–23.7 | 10.4 | 350 | 1.21 | 4.8 | 0.084 |
| May 24 | Morning and evening rain events with heavy rainfall and severe evening thunderstorm with a tornado | 14.4–27.7 | 21.6 | 627 | 7.29 | 24.3 | 0.313 |
a
Sample period begins at 08:00 on the date listed and ends at 07:00 the following day.
b
Rain events are defined based on rainfall rate (Bluestein and Howard, 1993)