The impact of polluted air on life expectancy

New index quantifies link between air quality and longevity but may not be the best guide to policy, reports Feng Hao
<p>Tiananmen Square, Beijing (Image:&nbsp;James Riker)</p>

Tiananmen Square, Beijing (Image: James Riker)

How much longer could you expect to live if you breathed clean air? If you’re in north-east China then it could be three or more years, according to the Air Quality Life Index (AQLI), which was launched last month in Beijing by the Energy Policy Institute at the University of Chicago (EPIC).

Unlike the well-known Air Quality Index, which highlights how good or bad the air quality is in a particular area, the AQLI shows the cost of breathing polluted air on life expectancy.

Search for a city on the AQLI map and you can see how much longer residents there could expect to live if PM2.5 levels reached the World Health Organization’s safe target of 10 micrograms per cubic metre of air.

The website was developed to give the public and policymakers a more direct understanding of the importance of reducing air pollution.

But some academics say it would not be appropriate to base environmental policies too firmly on the link between PM2.5 and life expectancy. If policies don’t take into account differences in wealth between regions, and between urban and rural areas, poorer populations may see longevity fall even further.

The true cost of PM2.5

The AQLI is based on two pieces of research that found life expectancy drops by 0.98 years for every increase of 10 micrograms of PM2.5 per cubic metre.

The index demonstrates the value of China’s success in reducing air pollution since 2013. The 12% drop in PM2.5 levels between 2013 and 2016 means that people in China can expect to live an average six months longer. Michael Greenstone, director of EPIC, calls this success huge and unprecedented.

Statistics show that Tianjin, one of China’s three most polluted cities in 2013, saw a drop of 14% in PM2.5 by 2016. If that improvement is sustained, the life expectancy of the city’s 13 million residents will increase by 1.2 years. Henan saw an even greater improvement over the same period, a fall in PM2.5 levels of 20%, equivalent to 1.3 years of extra life. Researchers found that if PM2.5 levels met the World Health Organization’s target, the average life expectancy would increase by 2.9 years.

“People always say tackling air pollution is too expensive, and that policymakers and the public want to see better evidence before making further efforts. AQLI uses the most important measure – life expectancy – to show directly how important tackling air pollution is,” Greenstone said.

Is a single index useful?

However, Jennifer Holdaway, co-director of the Forum on Health, Environment and Development (FORHEAD) said: “as an interdisciplinary researcher, I don’t think AQLI offers much new.”

She said that seven years ago, before the government took strong action on air pollution, many papers were published demonstrating the link between air quality and health. Now governments at all levels are pouring resources into environmental protection and almost everyone is aware of the health dangers of PM2.5. Therefore, there is little value in working out new shocking figures. What is needed in policymaking is consideration of how to achieve the maximum health benefit for the least social cost, which includes better addressing the needs of vulnerable populations.

According to a summary report from the FORHEAD team, life expectancy in China is still closely correlated with wealth. In the richest cities such as Shanghai, Tianjin and Beijing, life expectancy is higher than in the US or South Korea. Meanwhile, the poorest provinces, mostly in western China, have life expectancy on a par with the nations of Southeast Asia.

Wealthier parts of China have reached an income threshold where pollution control is likely to have greater public health benefits than additional increases in income. But in China’s poorer regions, economic growth is still likely to bring the biggest benefits to health.

Holdaway added that it is essential to ensure spending on improving air quality in those economically weaker regions does not harm other factors benefiting heath, such as stable employment or public investment in healthcare. If environmental protection competes for resources with other public services, money will need to be transferred between regions to offset that loss.

China has a pressing need both to sustain rapid economic growth and to improve health by controlling pollution.

In an interview with chinadialogue, Michael Greenstone said that in the end there is no easy option. Policy ultimately lies in the hands of local government. “I strongly suggest a more open attitude, allowing local governments which have a full understanding of the situation to experiment, to find a balance better suited to reality,” he said.

Who pays for blue skies?

Jiang Kejun, a researcher at the National Development and Reform Commission’s Energy Research Institute, agrees with Jennifer Holdaway that particular attention needs to be paid to fairness in tackling air pollution.

Since 2016 there has been a drive to clean up air in northern China by switching domestic heating from coal to natural gas or electricity. Jiang’s research has found that good progress has been made, but in some cases it will take time for the high costs to be absorbed.

Holdaway told chinadialogue that forceful environmental policies often come at the cost of future opportunities for poorer communities. For example, the Beijing-Tianjin-Hebei region’s most polluting industries – steel and cement makers – are also its biggest employers. Reducing output or closing factories means many workers must be let go. During the transition, new high-tech or service jobs may be created, but the laid-off workers don’t have the education or skills to take advantage.

“Historically, we see similar occurrences in Germany, the US and the UK as they deindustrialised, with increased inequality and job losses affecting entire families and future generations,” said Holdaway.