Table 3.

Mean PM_2.5, rescue events, and controller puffs by season, as well as the model estimates for the impact of PM2.5 on rescue events, varying by season

Season	Mean PM2.5	Mean rescue events	Mean controller puffs	Log(PM2.5) interaction
Spring	7.32	0.56	1.32	0.0876**
	(3.10)	(1.56)	(1.58)	(0.0409)
Summer	8.60	0.21	0.40	0.324***
	(4.38)	(1.30)	(1.65)	(0.117)
Fall	9.52	0.35	1.23	−0.157*
	(5.31)	(2.25)	(1.63)	(0.0872)
Winter	9.96	0.57	0.41	0.0767*
	(6.31)	(1.60)	(1.57)	(0.0446)

SDs/errors are given in parentheses. Model coefficients were estimated using Poisson fixed-effects models with log-log specifications. Estimates are based on 226,182 person-day observations. Time controls include day of week, year, and climate region-by-month fixed effects. Controls, measured as 4-d moving averages, include copollutants, 10° temperature and humidity bins, air pressure, wind speed, and days enrolled in program. Robust SEs, clustered by ID, are shown in parentheses. ***P < 0.01, **P < 0.05, *P < 0.1.