POLLEN COUNT

August 17, 2009

Pollen Count

Trees 1/m3

Grass 1/m3

Weeds 17/m3

NAB: Reading the Charts

The following Aeroallergen Network calculations are based on the data (per cubic meter) reported by all certified counting stations for trees, grasses and weeds.

NAB SCALE

TREE

0 Absent

1 - 14 Low

15 - 89 Moderate

90 - 1499 High

>1500 Very High

GRASS

0 Absent

1 - 4 Low

5 - 19 Moderate

20 - 199 High

>200 Very High

WEEDS

0 Absent

1 - 9 Low

10 - 49 Moderate

50 - 499 High

>500 Very High

These definitions would allow comparison between sites across the country. They are based on ecological measurements, not health effects. However, assuming dose/response relationships are the same across the country, the definitions are probably more appropriate than a definition based on local numbers. This does mean that, for some stations, some categories will never be high.