Table 1 Correlations among area characteristics, early childhood prevalence of asthma, and hospitalisations as a result of childhood asthma in New York City

	Street tree density	Population density	Percentage in poverty	Percentage black	Percentage Latino	Percentage near pollution source	Prevalence of asthma	Hospitalisations as a result of asthma
Street tree density		0.81***	–0.49**	0.18	0.08	–0.05	–0.66***	0.32
Population density	0.50***		0.40*	–0.21	–0.17	0.34*	0.65***	–0.29
Percentage in poverty	–0.54***	0.21		0.38*	0.54***	0.18	–0.27	0.25
Percentage black	–0.23	–0.02	0.40**		–0.52***	–0.22	0.19	0.35*
Percentage Latino	–0.52***	0.12	0.78***	0.11		–0.03	0.28	0.14
Percentage near pollution source	0.14	0.57***	0.38*	–0.04	0.29		–0.19	0.26
Prevalence of asthma	–0.54***	0.26	0.73***	0.44**	0.70***	0.26		0.58***
Hospitalisations as a result of asthma	–0.39*	0.23	0.75***	0.56***	0.65***	0.34*	0.83***

Partial correlation coefficients, shown above the diagonal, are adjusted for all other area characteristics shown; simple Pearson correlation coefficients are shown below the diagonal; characteristics and childhood asthma were assessed for 42 areas throughout New York City between 1995 and 2000.
*p⩽0.05; **p⩽0.01; ***p⩽0.001.