Less air pollution may be the upside of lockdowns

Is there any upside to lockdowns like the one currently in place in Victoria?
 
One major benefit is significantly less air pollution.
 
With far fewer cars and trucks on the road, emissions of nitrogen oxides, sulphur dioxide, volatile organic compounds (VOCs) and PM2.5 particles plunged in many countries as they entered lockdown.   
 
We now have a natural experiment playing out. Will lockdowns result in better health from avoided air pollution? Or will the mental health impacts of uncertainty and economic disruption caused by lockdowns be a net negative for health?
 
While the answer will not be known for some time, GP and Associate Professor Vicki Kotsirilos told newsGP the drop in air pollution is welcome.
 
‘That’s the upside to lockdown – cleaner air, less noise, less cars on the road and less emissions,’ she said.
 
Associate Professor Kotsirilos said the improvements will be mainly noticeable in urban areas, with a particular benefit likely for people living or working near major roads.
 
An associated benefit is the drop in noise pollution linked to the reduction in traffic.

‘Noise pollution is also harmful to health. Studies have found it increases risk of cardiovascular disease and hypertension,’ Associate Professor Kotsirilos said.
 
Five national academies of science last year called for urgent action on air pollution.
 
‘The scientific evidence is unequivocal: air pollution can harm health across the entire lifespan,’ they wrote in the Annals of Global Health.
 
‘It causes disease, disability and death, and impairs everyone’s quality of life. It damages lungs, hearts, brains, skin and other organs; it increases the risk of disease and disability, affecting virtually all systems in the human body.’
 
Data from the UK’s lockdown saw emissions of nitrogen oxide gases (NOx) drop by around 30–40% in urban areas, with a greater reduction for roadside areas, according to a June rapid evidence review.
 
‘We know NOx gases are harmful to human health, especially the health of children. These gases are known to increase the risk of asthma,’ Associate Professor Kotsirilos said.
 
The asthma link emerges from the Australian Child Health and Air Pollution Study, which found increases in nitrogen dioxide (NO₂) exposure are ‘significantly associated with increased odds of having current asthma’.

Associate Professor Vicki Kotsirilos says measuring how reductions in air pollution translate into health impacts will be interesting.
 
‘That’s a really important study,’ Associate Professor Kotsirilos said. ‘It found that even small increases in NO₂ exposure were significantly associated with increased risks of asthma and reduced lung function in children, even at rates below our current cut offs [the levels deemed safe].
 
‘There is a catch – asthma is multifactorial. So air pollution is not the only cause or trigger for asthma. There are other causes, such as stress.
 
‘There is well established scientific evidence that traffic-related air pollution at rates well below current air quality standards are associated with adverse health effects.
 
‘These impacts include increased mortality and morbidity such as cardiovascular disease, lung disease, asthma, and reduced lung function in children. It is now well established that children exposed regularly to NOx and PM2.5 particles from traffic have reduced lung function from an early stage.’
 
So what will the lockdown mean for human health?
 
‘How lockdown reductions in air pollution translate into health impacts will be interesting. The reductions are basically observational findings – how they are translated for GPs and patients remains to be seen,’ Associate Professor Kotsirilos said.
 
‘For example, during the pandemic, we may find there is a lower road toll, but lockdowns may lead to more depression, anxiety and mental health impacts.
 
‘We may find a reduction in asthma due to less air pollution, but people are spending much more time indoors and indoor air pollution can impact asthma, through dust mites and mould.’
 
With the rolling lockdowns around the world producing the single largest fall in fossil fuel use in 70 years, Associate Professor Kotsirilos believes the restrictions may precipitate positive change.
 
Vox reports that Professor Drew Shindell of Duke University in the US estimates air pollution is roughly twice as bad as previously thought for human health.
 
‘About twice as many people die in total as die just from the pathways we understand,’ Professor Shindell told the outlet. ‘We’ve been underestimating all along.
 
‘The well-understood pathways, things like strokes, lower-respiratory infections, and chronic obstructive pulmonary disease, only seem to capture about half the total.
 
‘When you look at the [new] studies, you find that air pollution seems to affect almost every organ in the human body.’
 
Associate Professor Kotsirilos said the long-term consequences of lockdowns could lead to wider take up of active transport modes such as walking or cycling as people avoid crowded public transport, as well as a potential shift to electric vehicles, which could drastically reduce air pollution from internal combustion engines.
 
‘This does offer an encouraging opportunity to protect the health of the planet where it directly impacts human health, to promote a healthier environment and ultimately promote better health for humans,’ she said.  
 
In a recent article in MJA Insight, Associate Professor Kotsirilos observed:
 
‘[T]he studies and the improvement of air quality during the pandemic do remind us why we should continue to urgently further research, tackle and tighten air pollution standards in Australia and the rest of the world. The pandemic gave us a welcoming glimpse of breathing clean air, making exercise outdoors safer.’ 
 
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air pollution asthma coronavirus COVID-19 lung disease respiratory health