OBJECTIVE: To quantify the number of avoidable annual deaths and associated economic benefits from meeting the World Health Organization (WHO) air quality guidelines for ambient concentrations for fine particulate matter (PM 2.5) for Member States of the WHO Western Pacific Region.

METHODS: Using the AirQ+ software, we performed a quantitative health impact assessment comparing country-level PM 2.5 concentrations with the 2005 and 2021 air quality guidelines recommended maximum concentrations of 10 and 5 μg/m 3, respectively. We obtained PM 2.5  data from the WHO Global Health Observatory (latest available year 2016), and population and mortality estimates from the United Nations World Population Prospects database for the latest 5-year period available (2015-2019), which we averaged to 1-year estimates. A risk estimate for all-cause mortality, based on a meta-analysis, was embedded within AirQ+ software. Our economic assessment used World Bank value of a statistical life adjusted to country-specific gross domestic product (latest available year 2014).

FINDINGS: Data were complete for 21 of 27 Member States. If these countries achieved the 2021 guidelines for PM 2.5, an estimated 3.1 million deaths would be avoided annually, which are 0.4 million more deaths avoided than meeting the 2005 guidelines. China would avoid the most deaths per 100 000 population (303 deaths) and Brunei Darussalam the least (5 deaths). The annual economic benefit per capita ranged from 5781 United States dollars (US$) in Singapore to US$ 143 in Solomon Islands.

CONCLUSION: Implementing effective measures to reduce PM 2.5 emissions would save a substantial number of lives and money across the Region.