Unless the world tackles climate change, deaths caused by air pollution are expected to increase by about 60,000 globally by 2030 - and 260,000 by 2100.
That's according to a new study which partly drew on data contributed by a Kiwi scientist, who says New Zealand won't be immune to effects despite its isolation.
The international study, published overnight in journal Nature Climate Change, adds to growing evidence that the overall health effects of a changing climate are likely to be overwhelmingly negative.
It was also the most comprehensive study yet on how climate change will effect health via air pollution, as it made use of results from several of the world's top climate-change modelling groups.
"As climate change affects air pollutant concentrations, it can have a significant impact on health worldwide, adding to the millions of people who die from air pollution each year, " said Jason West, who, with former graduate student and first author Raquel Silva, led the research at US-based University of North Carolina at Chapel Hill.
Hotter temperatures speed up the chemical reactions that create air pollutants like ozone and fine particulate matter, which affect public health.
Locations that became drier may also have worse air pollution because of less removal by rain, and increased fires and windblown dust.
As trees responded to higher temperatures, they would also emit more organic pollutants.
West and Silva used an ensemble of several global climate models to determine the number of premature deaths that would occur due to ozone and particulate matter in 2030 and 2100.
For each model, the team assessed the projected changes in ground-level air pollution that could be attributed to future climate change.
They then overlaid these changes spatially on the global population, accounting for both population growth and expected changes in susceptibility to air pollution.
Ultimately, West and Silva found that climate change was expected to increase air pollution-related deaths globally - and in all world regions except for Africa.
Specifically, five out of eight models predicted there would be more premature deaths in 2030, and seven of nine models in 2100.
"Our finding that most models show a likely increase in deaths is the clearest signal yet that climate change will be detrimental to air quality and health," West said.
"We also collaborated with some of the world's top climate model ing groups in the United States, United Kingdom, France, Japan and New Zealand, making this study the most comprehensive yet on the issue."
New Zealand atmospheric scientist Dr Guang Zeng contributed data using a sophisticated chemistry-climate model, which she has operated helped developed at Cambridge University and has operated at Niwa since 2008.
This modelled global surface ozone, following projected climate scenarios for 2100.
"Under the climate change projected for 2100, ozone and PM2.5 [microscopic particles that are a key measure of air pollution] will have negative impact on human health," she said.
"New Zealand is relative unaffected by ozone air pollution, due to its geographical location and remoteness, but does suffer from some urban particulate pollution.
"Climate change is a global phenomenon; it will modify pollutants' transport, and chemical and physical transformation, globally. New Zealand will not be immune to such global change."
A World Health Organisation report published last year nonetheless suggested New Zealand has some of the cleanest and safest air on the planet.
The report analysed data from more than 100 nations, comparing exposure to ambient air pollution and related death and illness, and showed New Zealand was either in the top five or 10 nations with the best results for concentrations of PM2.5, along with rates of deaths, disease and illness that could be attributed to pollution.