Changes in the hospitalization and ED visit rates for respiratory diseases associated with source-specific PM

Prior work found increased rates for emergency department (ED) visits for asthma and hospitalizations for chronic obstructive pulmonary disease per unit mass of PM(2.5) across New York State (NYS) during 2014 to 2016 after major reductions in ambient PM2.5 concentrations had occurred following implementation of various policy actions and major economic disruptions. The associations of source-specific PM(2.5) concentrations with these respiratory diseases were assessed with a time-stratified case-control design and logistic regression models to identify the changes in the PM(2.5) that have led to the apparently increased toxicity per unit mass. The rates of ED visits and hospitalizations for asthma and COPD associated with increases in source-specific PM2.5 concentrations in the prior 1, 4, and 7 days were estimated for 6 urban sites in New York State. Overall, there were similar numbers of significantly increased (n=9) and decreased rates (n=8) of respiratory events (asthma and COPD hospitalizations and ED visits) associated with increased source-specific PM(2.5) concentrations in the previous 1, 4, and 7 days. Associations of source-specific PM(2.5) concentrations with excess rates of hospitalizations for COPD for spark- and compression ignition vehicles increased in the 2014–2016 period, but the values were not statistically significant. Other source types showed inconsistent patterns of excess rates. For asthma ED visits, only biomass burning and road dust showed consistent positive associations with road dust having significant values for most lag times. Secondary nitrate also showed significant positive associations with asthma ED visits in the AFTER period compared to no associations in the prior periods. These results suggest that the relationships of asthma and COPD exacerbation with source-specific PM(2.5) are not well defined and further work will be needed to determine the causes of the apparent increases in the per unit mass toxicity of PM(2.5) in New York State in the 2014–16 period.