The associations between daily spring pollen counts, over-the-counter allergy medication sales, and asthma syndrome emergency department visits in New York City, 2002-2012

Table 2 Characteristics of tree pollen peaks and their correlation with the outcomes

Tree Pollen Type/outcome	Average peak calendar dates^{a, b} (S.D.)		Average 10^th-to-90^th % Duration^{b, c} days (S.D.)		Rank Correlation^d of Peak dates		Rank Correlation^d of Duration
Tree Pollen Type/outcome	Average peak calendar dates^{a, b} (S.D.)		Average 10^th-to-90^th % Duration^{b, c} days (S.D.)		OTC Allergy Med.	Asthma syndrome ED visits	OTC Allergy Med.	Asthma syndrome ED visits
Elm	31-Mar	(10.6)	15.0	(10.1)	0.55	0.50	-0.37	-0.38
Poplar	14-Apr	(9.9)	17.0	(6.9)	0.35	0.60	-0.15	-0.20
Maple	18-Apr	(13.5)	25.1	(10.2)	0.62	0.37	-0.28	-0.29
Birch	27-Apr	(5.7)	17.1	(9.6)	0.67	0.40	0.76	0.88
Beech	30-Apr	(5.7)	18.9	(6.1)	0.80	0.74	0.73	0.84
Ash	28-Apr	(7.3)	12.6	(4.0)	0.90	0.49	0.19	0.33
Sycamore/London planetree	28-Apr	(8.8)	12.5	(4.1)	0.91	0.51	0.32	0.49
Oak	4-May	(9.3)	12.5	(5.5)	0.92	0.66	0.86	0.85
Hickory	27-May	(6.7)	17.8	(5.7)	0.09	0.05	0.49	0.42
OTC Med Sales	2-May	(7.9)	44.7	(2.2)	NA	0.47	NA	0.89
Asthma Syndrome ED visits	11-May	(9.9)	46.5	(1.4)	0.47	NA	0.89	NA

Note: ^aFor each spring, the average peak date is defined as the average calendar date of the five highest pollen concentrations; ^bFor the outcomes, this computation was done for on and after April 15^th; ^cFor each spring, the 10^th-to-90^th percentile duration is the period between the dates with the 10^th and 90^th cumulative sum percentile of concentrations; ^dSpearman’s rank correlation between the average peak date or duration of tree pollen vs. that of the outcome across years. The bold-faced correlations are significant at alpha = 0.05 level

ISSN: 1476-069X