Time-series analysis of ambient PM(2.5) and cardiorespiratory emergency room visits in Lima, Peru during 2010-2016

INTRODUCTION: There have been no time-series studies of air pollution in Peru. Here we evaluate the effect of ambient PM(2.5) on emergency room (ER) visits in Lima. METHODS: We estimated daily PM(2.5) levels at a 1 km(2) resolution during 2010–2016 using ground measurements, satellite data, and chemical transport model simulations. Population-weighted average daily PM(2.5) levels were calculated for each district in Lima (n=40), and assigned to patients based on residence. ER visits for respiratory and circulatory diseases were gathered from 9 large public hospitals. Poisson regression was used to estimate the rate ratio for daily ER visits with change in daily PM(2.5), controlling for meteorology, time trends, and district. RESULTS: For each interquartile range (IQR) increase in PM(2.5), respiratory disease ER visits increased 4% (95% CI: 0–5%), stroke visits 10% (3–18%), and ischemic heart disease visits (adults, 18–64 years) 11% (−1%, 24%). Districts with higher poverty showed significantly stronger associations of PM(2.5) and respiratory disease ER visits than districts with lower poverty. Effects were diminished 24–42% using Lima-wide instead of district-specific PM(2.5) levels. CONCLUSION: Short-term exposure to ambient PM(2.5) is associated with increases in ER visits in Lima for respiratory diseases and stroke, and among middle-aged adults, ischemic heart disease.