Nav: Home

Traffic pollution drops in lockdown -- but other risks revealed by Manchester experts

May 07, 2020

Traffic pollution for most parts of the UK is plummeting thanks to the COVID-19 lockdown but more urban ozone - a dangerous air pollutant which can cause airway inflammation in humans - is probably being generated, say experts from The University of Manchester.

The analysis was led by Hugh Coe, Professor of Atmospheric Composition, plus air pollution expert Dr James Allan from Manchester's Department of Earth and Environmental Sciences. Their findings have been submitted in response to a call for evidence from the government's Department for Environment, Food and Rural Affairs (Defra).

According to Manchester research, levels of nitrogen oxides have shown reduction in most locations in the UK during mid-March and April when lockdown has been in full force - but the level of decline ranges from of 20 to 80 percent.

Manchester's city centre, for example, has seen a 70 per cent reduction in nitrogen oxides.

This drop can be attributed to the recent impact to traffic on the nation's roads, either private cars or public transport, as citizens were advised to stay at home to help prevent the spread of COVID-19.

"However, there is considerable site-to-site variability with some locations showing far less reduction than others," said Professor Coe. "In fact, a small number of sites have even shown a modest increase, for example in parts of Edinburgh.

"Whether this is due to changes in the number or type of vehicles now travelling in that particular area, changes in driving patterns or other causes is not clear but the reductions are certainly not uniform."

For example, levels of nitrogen oxides fall less in rural areas than urban areas; and they are higher in the morning than compared to later in the day. Unlike NO2, there was no evidence of a decrease in PM2.5 - tiny particulates that can make the air appear hazy.

"While these particle are produced by vehicles, they are also known to originate from domestic wood burning and chemical reactions involving emissions from industry and agriculture, so there has been no significant improvement in air quality in that regard," said Professor Coe.

At the same time, the Manchester team speculate that photochemical production of ozone may become more important in urban areas during summertime in these low NOx conditions.

This is an important finding because while ozone is extremely important for screening harmful solar ultraviolet (UV) radiation when present higher up in the atmosphere - it can be a dangerous air pollutant at the Earth's surface. Increasing surface ozone above natural levels is harmful to humans, plants, and other living systems because ozone reacts strongly to destroy or alter many biological molecules.

"Ozone is a strong oxidant and induces a range of health effects such as throat irritation and airway inflammation. It can reduce lung function and as a result worsens diseases such as bronchitis and asthma. In addition to human health impacts, ozone reduces plant growth and hence agricultural yields and chemically ages a wide range of polymers," explained Professor Coe

He added: "Observations in cities across the UK show marked decreases in nitrogen oxides but with corresponding increases in ozone during lockdown."

As nitrogen oxides reduce then photochemical production may well become more efficient and can lead to higher ozone concentrations in summertime as higher temperatures increase emissions of biogenic hydrocarbon from natural sources such as trees. These biogenic hydrocarbons significantly affect urban ozone levels.

As a result of the Manchester research government and local authorities will need to be alert to the potential increase in urban ozone during lockdown.

The Manchester team used the government's Automatic Urban and Rural Network (AURN) to help gather their nationwide data and the University's own Manchester Air Quality Supersite (MAQS), located in Fallowfield on the University campus. The work is carried out through the Manchester Environment Research Institute, which has a theme dedicated to Pollution, Human Health and Wellbeing.

The AURN is the UK's largest automatic monitoring network and it includes automatic air quality monitoring stations measuring oxides of nitrogen (NOx), sulphur dioxide (SO2), ozone (O3), carbon monoxide (CO) and particulate matter (including PM10, PM2.5).

Nitrogen oxides (NOx) is a generic term that includes nitric oxide (NO) and nitrogen dioxide (NO2) and these gases contribute to air pollution, including the formation of smog and acid rain, as well as affecting tropospheric ozone.
-end-


University of Manchester

Related Air Pollution Articles:

Exploring the neurological impact of air pollution
Air pollution has become a fact of modern life, with a majority of the global population facing chronic exposure.
Spotting air pollution with satellites, better than ever before
Researchers from Duke University have devised a method for estimating the air quality over a small patch of land using nothing but satellite imagery and weather conditions.
Exposure to air pollution during pregnancy is associated with growth delays
A new study by the Barcelona Institute for Global Health (ISGlobal) has found an association between exposure to air pollution during pregnancy and delays in physical growth in the early years after birth.
Nearly half of US breathing unhealthy air; record-breaking air pollution in nine cities
Amid the COVID-19 pandemic, the impact of air pollution on lung health is of heightened concern.
Air pollution linked to dementia and cardiovascular disease
People continuously exposed to air pollution are at increased risk of dementia, especially if they also suffer from cardiovascular diseases, according to a study at Karolinska Institutet in Sweden published in the journal JAMA Neurology.
New framework will help decide which trees are best in the fight against air pollution
A study from the University of Surrey has provided a comprehensive guide on which tree species are best for combating air pollution that originates from our roads -- along with suggestions for how to plant these green barriers to get the best results.
Air pollution is one of the world's most dangerous health risks
Researchers calculate that the effects of air pollution shorten the lives of people around the world by an average of almost three years.
The world faces an air pollution 'pandemic'
Air pollution is responsible for shortening people's lives worldwide on a scale far greater than wars and other forms of violence, parasitic and insect-born diseases such as malaria, HIV/AIDS and smoking, according to a study published in Cardiovascular Research.
Air pollution in childhood linked to schizophrenia
Children who grow up in areas with heavy air pollution have a higher risk of developing schizophrenia.
Air pollution can worsen bone health
A new study by the CHAI Project with over 3,700 people in India associates air pollution with a higher risk to develop osteoporosis.
More Air Pollution News and Air Pollution Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at Radiolab.org/donate.     You can read The Transition Integrity Project's report here.