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Nitrogen Dioxide

Hong Kong can create its own smog, researchers say

Scientists from Hong Kong and Macau found one day in which pollutants were formed when dirty air was not blowing from the north

Smoggy days are often blamed on regional pollution and weather, but at least one recent scientific study has shown that the city can, under the right conditions, “form its own smog”.

The study by Hong Kong and Macau air scientists argued that a rapid build-up of particulate matter in the air – a key component of smog – was possible even in the absence of northerly winds that can transport pollutants from afar.

The evidence boiled down to at least one particular sunny September day in Hong Kong in which a “land-sea breeze” pattern formed along with weak winds far below average speeds.

The scientists observed a rapid rise of photochemical activity during mid-afternoon, in which ozone and nitrogen dioxide skyrocketed along with increasing sunshine.

“It is clear that there was a rapid increase in particulate matter (PM) concentration on this day when we were not really affected by external meteorological conditions. It’s not easy to argue in this case that winds were blowing PM to Hong Kong from the region ,” said co-author Professor Chan Chak-keung, dean of City University’s school of energy and environment.

The culprits, he said, were most likely local sources such as vehicles or industrial emissions, which contain nitrogen oxides and volatile organic compounds. The latter pollutant is also found in products such as organic solvents, paints and printer inks.

Chan’s team investigated “episodes” – days with high PM concentrations – in one-month periods in each of the four seasons from 2011 to 2012 at the University of Science and Technology’s air quality research supersite.

Other episodes across the seasons were also observed with high local photochemical activity, but those days also came under the influence of transported air from the north, making it less clear what was actually local or regional.

The paper was published in scientific journal Atmospheric Chemistry and Physics in November.

“Of course, regional sources play a role but [this research] shows that under the right conditions, PM can build up and Hong Kong can form its own photochemical smog.”

Photochemical smog is created when nitrogen oxides react with volatile organic compounds in the air under sunlight. It leads to the formation of ozone. This hazardous pollutant facilitates the formation of the tiny particles, small enough to be inhaled deep into the lungs and even into the bloodstream.

The particulate matter in the air lowers visibility, turning the sky smoggy and gives it a lurid orange tint at dusk.

The Environmental Protection Department usually points to meteorological influences such as northeast monsoons when the air quality health index hits “very high” health risk levels.

During a bout of high pollution last Thursday, it said: “Hong Kong is being affected by an airstream with higher background pollutant concentrations. The light wind hinders effective dispersion of air pollutants.”

It added that the formation of ozone and fine particulates during the daytime resulted in high pollution in the region.

Chan said most smoggy days were doubtless a result of regional factors or pollution. But he said the study’s findings warranted more research on how PM was formed and pinpointing its sources.

Source URL: http://www.scmp.com/news/hong-kong/health-environment/article/2076236/hong-kong-can-create-its-own-smog-researchers-say

Hong Kong enjoys a breath of fresh air but it’s not enough to meet annual quality goals

Lower concentrations of harmful pollutants were recorded last year but roadside-dominant nitrogen dioxide remains a headache for the city

Lower concentrations of harmful pollutants were recorded last year, including the tiny particulates that can penetrate deep into the lungs – but roadside- dominant nitrogen dioxide remains a headache for the city, with most figures failing annual air quality targets.

And while ambient concentrations of hazardous ozone fell for the second consecutive year, they are proving stubbornly hard to cut having increased 15 per cent since 1999.

The preliminary air quality data for 2016 was released by the Environmental Protection Department yesterday.

At roadsides, concentrations of respirable suspended particulates (PM10) dropped by 15 per cent, fine suspended particulates (PM2.5) by 12 per cent, and sulphur dioxide
(SO2) by 10 per cent.

Similar drops were recorded at general stations. Fewer hours and days of high health risk air were recorded at both ambient and roadside stations last year.

But although roadside concentrations of nitrogen dioxide (NO2) – a product of fuel combustion – fell by 17 per cent, the average annual concentration of 82 micrograms per cubic metre of air was still more than double the annual air quality objective target of just 40.

All three roadside monitoring stations also fell short of the air quality objectives for acceptable annual NO2 levels last year.

“Roadside NO2 remains a very big challenge as reduction technologies available now are not that sophisticated,” assistant director of air policy Mok Wai-chuen said.

At roadsides, concentrations of respirable suspended particulates (PM10) dropped by 15 per cent, fine suspended particulates (PM2.5) by 12 per cent, and sulphur dioxide
(SO2) by 10 per cent.

Similar drops were recorded at general stations. Fewer hours and days of high health risk air were recorded at both ambient and roadside stations last year.

But although roadside concentrations of nitrogen dioxide (NO2) – a product of fuel combustion – fell by 17 per cent, the average annual concentration of 82 micrograms per cubic metre of air was still more than double the annual air quality objective target of just 40.

All three roadside monitoring stations also fell short of the air quality objectives for acceptable annual NO2 levels last year.

“Roadside NO2 remains a very big challenge as reduction technologies available now are not that sophisticated,” assistant director of air policy Mok Wai-chuen said.

He believed improvements in particulate pollution were a result of policy measures such as an ongoing scheme to phase out old diesel commercial vehicles progressively and new laws requiring ships at berth to switch to low- sulphur fuel.

“This proves our policies to tackle particulate matter have been effective,” he said, adding that other measures such as tightening emission controls are being looked at.

Mok claimed the most severely polluted days were a result of ozone, a regional problem, either from pollution blowing in from the Pearl River Delta or meteorological
conditions such as tropical cyclones.

Ozone is formed through a reaction of nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the air and under sunlight. It is a main component of photochemical smog – which gives a dusk sky a lurid, orange tint – and at elevated levels, can cause or aggravate respiratory diseases.

Asked if the toxic smog plaguing northern China could have drifted south, he said “it could not be ruled out” but “was of low possibility”.

The Clean Air Network’s Loong Tsz-wai said Mok’s meteorological explanations diverted attention from the most pressing issue, which was roadside pollution and the
“uncontrolled growth” of road vehicles.

“Most of our exposure to bad air is at roadside,” he said. “NO2 concentrations may be going down but the effectiveness of exhaust pipe policies could be easily offset over the years if the number of private cars is not curbed.”

Wang Tao, chair professor of atmospheric environment at Polytechnic University, said the increase in regional ozone had indeed slowed since 2013, but not fallen. More control of precursors, such as VOC and NOX, were needed on both sides of the border, he said.

Source URL: http://www.scmp.com/news/hong-kong/healthenvironment/article/2059691/hong-kong-enjoys-breath-fresh-air-its-not-enough

Air pollution could be to blame for hundreds of traffic accidents, warn researchers

Air pollution could be responsible for hundreds of car accidents a year, according to the London School of Economics.

http://www.telegraph.co.uk/science/2016/10/03/air-pollution-could-be-to-blame-for-hundreds-of-traffic-accident/

A study looking a five years of data showed that when levels of nitrogen dioxide (NO2) rise just one microgramme per cubic metre, the number of collisions rises by two per cent.

Although it might seem that effect could be explained by more traffic on the roads, and therefore more pollution and more accidents, the researchers found that the increase remained even when adjusting for the extra traffic

Instead, they believe that the toxic air impairs driver fitness, while watery eyes and an itchy nose could also be distracting for motorists.

A recent study found that air pollution inside a car can be more than double that on the outside because the NO2 builds up in a small space.

Lead researcher Lutz Sager of the Grantham Research Institute on Climate Change and the Environment at the LSE said: “Although it has already been shown that air pollution adversely affects human health and the ability to carry out mental tasks, this is the first published study that assesses the impact on road safety.

“The analysis identifies a causal effect of air pollution on road accidents, but I can only speculate about the cause of the link.

“My main theory is that air pollution impairs drivers’ fitness. However, other explanations are possible such as air pollution causing physical distractions, perhaps an itching nose, or limiting visibility.”

Air pollution can result from many different toxins, including carbon monoxide, nitrogen dioxide, sulphur dioxide, small particulate matter and ozone. But it was NO2 which was found to have the biggest impact.

Mr Sager, a postdoctoral candidate, divided the UK into a grid of 32 areas each covering about 4784 square miles (7700 sq km) and mapped accidents to the level of air pollution between 2009 and 2014 provided by the Department for the Environment (Defra)

He found a rise in the concentration of nitrogen dioxide of just one microgramme per cubic metre above the daily average is sufficient to increase the average number of accidents each day by two per cent, with the biggest effect occurring in cities.

Mr Sager calculated that in the area containing west London, which suffers from some of the highest levels of air pollution, a cut of about 30 per cent in the concentration of NO2 could reduce the number of road accidents every day by almost 5 per cent.

Levels of NO2 in polluted areas of London can reach beyond 97 microgrammes per cubic metre on average.

There are around 150,000 collisions in which someone is injured in Britain every year so preventing just two per cent of crashes could avert thousands of accidents.

Mr Sager added: “Whatever the exact mechanisms responsible, the robust finding of a significant effect of air quality on road safety is important given the high cost of road traffic accidents through damage to vehicles and deaths and injuries to people every day.

“Although this analysis has used data for the United Kingdom, I think my findings are relevant to other parts of the world. These additional costs from traffic accidents strengthen the case for reducing air pollution, particularly in congested cities.

“My analysis suggests that the causal effect of air pollution on road traffic accidents measured in this study more likely stems from nitrogen dioxide or other pollutant gases rather than particulate matter.”

However other experts were more sceptical about the link between air pollution and accidents.

AA president Edmund King said: “If you think about areas which are high in air pollution they are a lot busier, with taxis and buses and lorries and where you have a greater mix of traffic you tend to have more accidents.

“It would be hard to tease apart whether a crash is caused by a driver wiping his eyes because of pollution or the type of traffic which is to blame.

“If you look at Mumbai and New Delhi where you have some of the worst air pollution, yes you have far more accidents, but it is also far more chaotic.

“So I think this research may be far-fetched as I think it would be very difficult to prove that a driver’s fitness is impaired by pollution.”

The results of the study are published today as a working paper, and will be submitted for peer review in the coming weeks.

Something in the air: Is Hong Kong’s pollution problem worsening?

https://www.timeout.com/hong-kong/blog/something-in-the-air-is-hong-kongs-pollution-problem-worsening-092116

The government is trumpeting recent figures that show air pollution is significantly decreasing but is the news as good as it sounds? And what other forms of pollution should Hongkongers worry about?

Christie Tse and Joyce Au find out

“See the people walking by right now? Leisurely walking past, enjoying life, breathing the fresh air?” asks Dr Bob Tsui, vicechairman of NGO Clear The Air, as he points out his office window overlooking the streets of Jordan. You are being ‘attacked through your eyes, your cornea, your nostrils, your mouth and your skin” all the time, he follows up. As you’re reading this, tiny deadly pollution particles called magnetites are slowly moving up your nostrils, penetrating your brain tissue, nervous system and lungs. In a crowded, polluted city like Hong Kong, your body is constantly under attack, every second of every day according to Dr Tsui.

According to government statistics, though, air pollution has been decreasing for several years now. The Environmental Protection Department reckons that between 2011 and 2015, average concentrations of PM10, PM2.5, nitrogen dioxide and sulphur dioxide at roadside monitoring stations fell by 26 percent, 21 percent, 19 percent and 33 percent, respectively. The figures sound impressive and the government has been running adverts on TV trumpeting its success at clearing the air.

However, all is not rosy. Recent studies conducted by scientists in Mexico City have discovered a correlation between 100 and 200 nanometer magnetites released through the exhaust pipes of taxis and buses and the development of Alzheimer’s disease. This new information has sparked concern in the local scientific community since roadside pollution remains one of the leading causes of air pollution in our jam-packed city. “In the past 20 years, Hong Kong has not once met its own Air Quality Index standard or that of the World Health Organisation’s,” exclaims Patrick Fung, CEO of NGO Clean Air Network. Paul Zimmerman, Southern District councillor, believes this is unforgiveable, as ‘it’s almost like violence is around you the whole time’, he tells us.

And that’s not the half of it. You may think you can avoid pollution by simply turning recluse and staying at home, but you’d be very wrong.

Studies conducted at the University of Hong Kong reveal that our own kitchens discharge carcinogenic particles into the air every time food is made with vegetable oil. Dr Tsui states that vegetable oil is ‘the most dangerous oil you can use’ since it contributes to air pollution. Clear The Air has published an article that details the process by which vegetable oil, when subjected to high temperatures, oxidises into cancer causing chemicals. “People wonder how they get sick because they eat well all their lives,” Dr Tsui remarks, “but they don’t realise they’re constantly surrounded by these cancerous particles.”

The worst part of all of this is that the toxic kitchen discharge is completely preventable. According to Dr Tsui, the government has the ability and resources to go into restaurants and check their deep friers for dangerous particles.

“It’s a simple test strip and they can do it very easily,” he tells us. “But I have made this announcement for years and the government has not taken any action!” By placing steam jet filters in the kitchen stove, the carcinogenic particles could be released into water. This wouldn’t contaminate the water, according to Dr Tsui, because by the time the dangerous particles pass through the filter and hit the water, many things happen chemically to make the particles no longer harmful.

And cooking oil and air pollution are not the only worries we need have in Hong Kong. After the waves of rubbish that washed up on our beaches over the summer, Hongkongers should be acutely aware of the problem of landfill. Around 30 percent of landfill is made of Styrofoam and in 500 years, that same Styrofoam will still not have decomposed. What’s worse, Styrofoam is mainly composed of styrene, an extremely dangerous chemical that has been linked to cancer, vision and hearing loss, impaired memory and concentration, damage to the nervous systems and depression. “Styrene is dangerous,” Dr Tsui declares. “Styrene is vicious. Styrene should not exist in the food chain and yet, every restaurant [in Hong Kong] today still uses Styrofoam takeout boxes.” Worryingly, when we eat hot food or drink hot liquid from Styrofoam plates, boxes or cups, it’s possible for us to consume the styrene that leaches out of the hazardous material.

Once we’ve ingested these dangerous chemicals, they can swim into our bloodstreams, penetrate our organs and cause irrevocable damage to our bodies. Even Styrofoam that’s out in the ocean can ultimately affect us since when marine life, such as fish, consume it, styrene enters the food chain and eventually, Dr Tsui believes, ‘we’ll eat the darn thing’.

Dr Tsui asks: “How can the government be so blind and be so idiotic to allow this to go on?” Just as toxic kitchen discharges are preventable, so too is the use of Styrofoam. Not just in the food industry but all industries. Instead of using Styrofoam boxes for takeaway meals, companies should start using biodegradable containers, Clear The Air advocates. This minor innovation is also very much within the grasp of companies’ capabilities. Fibre generated from corn can be made to make the boxes and then coated in honey wax. Best of all, these resources are biodegradable.

Another solution that the government and corporations can consider implementing, according to Clear The Air, is changing the original chemical composition used to make Styrofoam. The government could order corporations to put titanium dioxide polymers in the Styrofoam so that once the material is dumped on landfill or into the ocean and exposed to UV light, the Styrofoam will disintegrate into carbon dioxide and water, which equates to less harmful pollution.

There are many little things we can do to contribute to a more environmentally friendly society, such as switching off the lights when we leave a room, turning off the air conditioner when we leave the house, adding insulated panels to our windows and attaching solar panels to our roofs. The list is endless. But while every little helps, these changes are too-little-too-late because, ultimately, it is up to our local authority to enact the kind of legislative reform required to make a real difference. As Dr Tsui so clearly puts it: “No matter how rich or how poor you are, you are subjected to this kind of invisible attack. The government needs to stop with the [political games] and start working on practical solutions to eradicate pollution-induced cancer.”

Unfortunately, when it comes to asking the government for help, every issue seems like an urgent matter. Compared to global threats such as deadly diseases like the zika virus or even more mundane local issues like affordable housing, the largely invisible problem of pollution is all too often pushed to the bottom of the list of priorities.

The public, not just the government, underestimate the drastic consequences of air contamination since the effects are not as apparent as many other similarly pressing matters. But pollution is an urgent problem because it surrounds us all. It’s in the air we breathe, the places we walk and the supposedly safe confines of our own homes. We live and breathe pollution whether we like it or not, so it’s about time we paid attention.

For more information visit cleartheair.org.hk.

Sadiq Khan to more than double size of London’s clean air zone

New mayor of London calls air pollution ‘our biggest environmental challenge’ and plans to bring the increased ultra low emission zone into force early

https://www.theguardian.com/environment/2016/may/13/sadiq-khan-to-double-size-londons-clean-air-zone-pollution

The new mayor of London Sadiq Khan has made his first major policy announcement, unveiling plans to substantially increase the size of London’s clean air charging zone to tackle the capital’s illegal air pollution levels.

The Ultra Low Emissions Zone (ULEZ) – which could also now come into force earlier than planned – will require drivers of the 2.5m oldest and dirtiest vehicles to pay a charge. Owners of cars that fail to meet the standards will pay a £12.50 charge, separate to the congestion charge.

The scheme is intended to act as an incentive to drivers to use cleaner vehicles or alternative transport to reduce the levels of nitrogen dioxide, a toxic gas produced by diesel vehicles.

Under Khan’s plans, which will now be subject to a public consultation, the ULEZ will stretch from the north to south circular roads in London rather than just the much smaller congestion charge zone in central London as currently planned. Officials said the area covered will more than double in size.

Khan said his predecessor, Boris Johnson, had been too slow to act and had left the city a “laughing stock” internationally, and the government had been “hopelessly inactive” on the issue. Officials said the ULEZ, under a consultation to be published within weeks, could now come into force as soon as 2019 rather than the original plan of 2020.

“I have been elected with a clear mandate to clean up London’s air – our biggest environmental challenge,” Khan said at a school in east London. He said London had only acted on pollution in the past after emergencies, such as the Great Smogs of the1950s: “But I want to act before an emergency, which is why we need big, bold and sometimes difficult policies if London is to match the scale of the challenge.”

The mayor’s office also said an extra charge on the most polluting vehicles would be brought in from 2017, which would be administered by the congestion charge system but be separate to the congestion charge. It is not yet clear what that charge will be.

Khan chatted with pupils and sowed seeds with them at a rooftop garden of a primary school in Aldgate, which is situated on a busy road packed with cars and buses. Sir John Cass’s Foundation is equipped with its own pollution sensors as well as one from the wider London Air Quality Network, decorated with a design created by schoolchildren.

“For me it can’t be right that this school on three occasions last year has to make the call whether to allow children to play in the playground breathing in this dangerous stuff or play indoors,” Khan told the Guardian.

He said the issue was very personal to him because of his asthma, but also as a father of two daughters, and as someone with nephews and nieces. “At the age of 45 I’ve been diagnosed with asthma. All the experts say that one out of three people who have asthma could be because of air quality.”

Khan said that under eight years of Boris Johnson the city’s reputation had gone from: “being one of the world-leading cities [in terms of air pollution], according to people around the world, to being at best mediocre.” He added the city had gone from having an earlier reputation for leadership on climate change and air quality but was now “a laughing stock around the world.”

A study by King’s College London last year found that nearly 9,500 people in the capital die early because of air pollution. Earlier this year it took parts of London just one week to breach annual limits, and a major global study by the World Health Organisation on Thursday found the city breached its guideline limits for two harmful types of particulate pollution.

Alan Andrews of ClientEarth, which has sued the government over the illegal pollution levels in London and other cites, said the mayor’s plan was a “hugely positive announcement”.

“We will have to wait and see if the detail of the mayor’s proposals matches his ambition. With air pollution causing over 9,000 deaths a year in London it is vital that all options to solve this problem are on the table. It will be crucial that the ULEZ ensures vehicles meet the most stringent emission standards when driving on London’s roads, not just in discredited laboratory tests,” he said.

“Today’s announcement, coming so early in the new mayor’s term, should send a clear message to the UK government that ambitious and bold action is needed. The government must now up its game so that the whole country can breathe cleaner air.”

Caroline Russell, Green party London Assembly member, said: “While I warmly welcome the mayor’s intention to expand the ULEZ to the north and south circular, it’s essential that all outer London boroughs should also have the ability to opt in right from the beginning.”

But Friends of the Earth said that while it welcomed such a swift plan and expanded ULEZ, Khan was sending mixed messages by clearing an obstacle to City Airport’s expansion earlier this week. “It is confusing that this announcement comes in the same week that Sadiq Khan has removed a key hurdle in the expansion of City Airport which will only add to London’s dirty air woes,” said its campaigner, Sophie Neuburg.