Changes in respiratory and cardiovascular morbidity air pollution risk and attributable burden in New York City

Air quality in New York City has improved substantially in the past 2 decades due to reductions in both transported aerosols and local emissions. We estimated the short-term risk changes for three criteria air pollutants and corresponding attributable burdens.

Trends in percent excess risk (PER) per same pollution increment and attributable counts and fractions for fine particles (PM_2.5), nitrogen dioxide (NO₂), and ozone (warm season only) were examined for Emergency Department (ED) visits (2005-2019) and hospitalizations (2000-2019) for youth asthma (ages 5-17), adult cardiovascular disease (CVD) (ages 40+), and older adult respiratory causes (ages 65+). Time-series models considered up to 3-day lag, adjusted for seasonal trends, day of week, holidays, and concurrent and delayed temperature.

Most pollutant-outcome pairs did not exhibit trends in PERs over time. NO₂-attributable burden was higher than PM_2.5 burden for asthma and CVD outcomes. We estimated about 4500 (17%) youth asthma ED visits and 1000 (2%) CVD hospitalizations on average annually (2005-2019) attributable to NO₂ compared with 1900 (7%) youth asthma ED visits and 450 (1%) CVD hospitalizations attributable to PM_2.5. NO₂- and PM_2.5-attributable health impacts declined about 50%-70%, driven by decreasing pollution levels and total morbidity burden depending on outcome, pollutant, and season. Ozone-attributable burden was mostly unchanged over time.

With less decline and greater attributable impact than PM_2.5, NO₂ is increasingly important for measuring morbidity impacts from local sources (i.e., traffic and buildings) in New York City. Ozone impacts from regional source emissions persist.