Quantitative Health Impact Assessment in Yokohama Based on NO₂ Concentrations for the Years 2000–2018

Abstract

An air pollution health risk assessment (AP-HRA), which estimates various health benefits if the ambient air pollution concentrations could be reduced to a target reduction value, is being conducted worldwide. In Japan, however, few studies have been conducted within the framework of the AP-HRA. In this study, with the aim of quantitatively evaluating the health effects of the long-term exposure to recent NO₂ concentrations and providing information that will contribute to air pollution control measures, the number of annual deaths that could be reduced if the annual mean NO₂ concentration of 20 µg/m³ was achieved in Yokohama City and the percentage contribution from NO₂ was determined using the estimated values from AirQ+ developed by WHO/Europe. The study of the annual average concentrations in 2018 estimated that it could prevent approximately 1,071 (95% CI: 508–1,638) deaths in the entire city of Yokohama. It corresponds to 3.4% (95%CI: 1.6–5.2%) of the deaths. It will be necessary to examine the size of the area to be studied and organize various parameters, as well as to proceed with the quantitative health impact assessment of other major air pollutants, such as PM_2.5 and O₃, when their concentrations are reduced by promoting air pollution control measures.