Figure 2.

Percent increases and 95% confidence intervals for admission to the hospital for renal, heat or respiratory causes among individuals aged 65 years and older for the six-day cumulative effects of extreme heat (EH, temperature > 97^th percentile) vs. non-heat (temperature < 90^th percentile) among individuals with (high) or without (low) the characteristic (individual level) or among individuals residing in ZIP codes in the 75^th percentile (high) or 25^th percentile (low) of the characteristic (ZIP-code level), holding the other characteristics at the study-wide median values, by quartiles of citywide air conditioning prevalence (ACP), May–September, 1992–2006. (See Table S2 for corresponding values.)