Tag Archives: air

The pressure is on for Australia to accept the coronavirus really can spread in the air we breathe

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C Raina MacIntyre, UNSWMore than a year into the pandemic, the World Health Organization (WHO) and US Centers for Disease Control finally changed their guidance to acknowledge SARS-CoV-2, the virus that causes COVID-19, can be transmitted through the air we breathe.

In Australia, we’ve just had the latest leak from hotel quarantine, this time in South Australia. Investigations are under way to find out whether a man may have caught the virus from someone in the hotel room next to his, before travelling to Victoria, and whether airborne transmission played a role.

These examples are further fuelling calls for Australia to officially recognise the role of airborne transmission of SARS-CoV-2. Such recognition would have widespread implications for how health-care workers are protected, how hotel quarantine is managed, not to mention public health advice more broadly.

Indeed, we’re waiting to hear whether official Australian guidelines will acknowledge the latest evidence on airborne transmission, and amend its advice about how best to protect front-line workers.

The evidence has changed and so must our advice

At the beginning of the pandemic, in the absence of any scientific studies, the WHO said the virus was spread by “large droplets” and promoted handwashing. Authorities around the world even discouraged us from wearing masks.

A false narrative dominated public discussion for over a year. This resulted in hygiene theatre — scrubbing of hands and surfaces for little gain — while the pandemic wreaked mass destruction on the world.

But handwashing did not mitigate the most catastrophic pandemic of our lifetime. And the airborne deniers have continually shifted the goalposts of the burden of proof of airborne spread as the evidence has accrued.



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What does the evidence say?

SARS-CoV-2 is a respiratory virus that multiplies in the respiratory tract. So it is spread by the respiratory route — via breathing, speaking, singing, coughing or sneezing.

Two other coronaviruses — the ones that cause MERS (Middle Eastern respiratory sydrome) and SARS (severe acute respiratory syndrome) — are also spread this way. Both are accepted as being airborne.

In fact, experimental studies show SARS-CoV-2 is as airborne as these other coronaviruses, if not more so, and can be found in the air 16 hours after being aerosolised.

Several hospital studies have also found viable virus in the air on a COVID-19 ward.

Established criteria for whether a pathogen is airborne scores SARS-CoV-2 highly for airborne spread, in the same range as tuberculosis, which is universally accepted as airborne.

A group of experts has also recently outlined the top ten reasons why SARS-CoV-2 is airborne.

So why has airborne denialism persisted for so long?

The role of airborne transmission has been denied for so long partly because expert groups that advise government have not included engineers, aerosol scientists, occupational hygienists and multidisciplinary environmental health experts.

Partly it is because the role of airborne transmission for other respiratory viruses has been denied for decades, accompanied by a long history of denial of adequate respiratory protection for health workers. For example, during the SARS outbreak in Canada in 2003, denial of protection against airborne spread for health workers in Toronto resulted in a fatal outbreak.

Even influenza is airborne, but this has been denied by infection control committees.



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What’s the difference between aerosols and droplets?

The distinction between aerosols and droplets is largely artificial and driven by infection control dogma, not science.

This dogma says large droplets (defined by WHO as larger than 5 micrometres across) settle to the ground and are emitted within 2 metres of an infected person. Meanwhile, fine particles under 5 micrometres across can become airborne and exist further away.

There is in fact no scientific basis for this belief. Most studies that looked at how far large droplets travelled found the horizontal distance is greater than 2 metres. And the size threshold that dictates whether droplets fall or float is actually 100 micrometres, not 5 micrometres. In other words, larger droplets travel further than what we’ve been led to believe.

Leading aerosol scientists explain the historical basis of these false beliefs, which go back nearly a century.

And in further evidence the droplet theory is false, we showed that even for infections believed to be spread by droplets, a N95 respirator protects better than a surgical mask. In fact airborne precautions are needed for most respiratory infections.

Why does this difference matter?

Accepting how SARS-CoV-2 spreads means we can better prevent transmission and protect people, using the right types of masks and better ventilation.

Breathing and speaking generate aerosols. So an infected person in a closed indoor space without good ventilation will generate an accumulation of aerosols over time, just like cigarette smoke accumulates.

A church outbreak in Australia saw spread indoors up to 15 metres from the sick person, without any close contact.

Masks work, both by preventing sick people from emitting infected aerosols, and by preventing well people from getting infected. A study in Hong Kong found most transmission occurred when masks weren’t worn inside, such as at home and in restaurants.



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Coughing generates more aerosols

The old dogma of droplet infection includes a belief that only “aerosol generating procedures” — such as inserting a tube into someone’s throat and windpipe to help them breathe — pose a risk of airborne transmission. But research shows a coughing patient generates more aerosols than one of these procedures.

Yet we do not provide health workers treating coughing COVID-19 patients with N95 respirators under current guidelines.

At the Royal Melbourne Hospital, where many health worker infections occurred in 2020, understanding airflow in the COVID ward helped explain how health workers got infected.

Think about it. Airborne deniers tell us infection occurs after a ballistic strike by a single large droplet hitting the eye, nose or mouth. The statistical probability of this is much lower than simply breathing in accumulated, contaminated air.

The ballistic strike theory has driven an industry in plastic barriers and face shields, which offer no protection against airborne spread. In Switzerland, only hospitality workers using just a face shield got infected and those wearing masks were protected.



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In hotel quarantine, denial of airborne transmission stops us from fixing repeated breaches, which are likely due to airborne transmission.

We need to select quarantine venues based on adequacy of ventilation, test ventilation and mitigate areas of poor ventilation. Opening a window, drawing in fresh air or using air purifiers dramatically reduce virus in the air.



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We need to provide N95 respirators to health, aged-care and quarantine workers who are at risk of high-dose exposure, and not place them in poorly ventilated areas.

It’s time to accept the evidence and tighten protection accordingly, to keep Australia safe from SARS-CoV-2 and more dangerous variants of concern, some of which are vaccine resistant.The Conversation

C Raina MacIntyre, Professor of Global Biosecurity, NHMRC Principal Research Fellow, Head, Biosecurity Program, Kirby Institute, UNSW

This article is republished from The Conversation under a Creative Commons license. Read the original article.

There’s no evidence the new coronavirus spreads through the air – but it’s still possible

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Ian M. Mackay, The University of Queensland and Katherine Arden, The University of Queensland

A recent announcement by a Chinese health official suggested the new coronavirus might spread more easily than we thought, via an “airborne route”. The virus is now known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), while the name of the disease it causes is now called COVID-19.

The Chinese Center for Disease Control and Prevention almost immediately corrected the announcement, noting SARS-CoV-2 was not known to be an airborne virus.

The centre confirmed the virus appears to spread via droplets, direct contact and by coming into contact with contaminated surfaces and objects. The World Health Organisation agrees.

So far no infectious virus has been recovered from captured air samples. This would need to occur to demonstrate the virus was airborne.



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What’s the difference between airborne and droplet spread?

When we sneeze, cough or talk, we expel particles in a range of sizes.

The bigger, wet droplets larger than 5-10 millionths of a meter (µm or micrometre) fall to the ground within seconds or land on another surface.

These wet droplets are currently considered to be the highest risk routes for the SARS-CoV-2.

But smaller particles aren’t implicated in the spread of SARS-CoV-2.

Smaller particles remain suspended in the air and evaporate very quickly (at less than one-tenth of a second in dry air). They leave behind gel-like particles made of proteins, salts and other things, including viruses.

These leftovers are called “droplet nuclei” and can be inhaled. They may remain aloft for hours, riding the air currents through a hospital corridor, shopping centre or office block. This is what we mean when we talk about something being airborne.



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But there’s more to airborne spread. To infect humans, the droplet nuclei need to contain infectious virus. The virus must be able to land on our mucous membranes – the soft lining of our ears, nose, conjunctiva (eyelid), throat and digestive tract and it must be able to enter our cells and replicate.

There also needs to be enough virus to overcome our early immune responses to the invader and start an infection.

So a few stars have to align for airborne infection to result.

When we cough, sneeze or talk, we expel particles in a range of sizes.
Shutterstock

But airborne transmission wouldn’t be a shock

We already know the measles virus can remain aloft in a room for up to 30 minutes after an infected person leaves it.

Likewise, the MERS coronavirus has been captured in infectious form from hospital air samples and found to be infectious.

So there is some precedent.

Other viruses that can be infectious via an airborne route include rhinoviruses (the main causes of the common cold) and flu viruses.

The ability for common respiratory viruses to spread via airborne particles means it wouldn’t be a shock to find SARS-CoV-2 also had this capability.

But there is no evidence this is currently occurring.



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Why would airborne spread be such a problem?

Airborne spread would mean the virus could travel further. It could spread through unfiltered air conditioning ducting and reach people further away from the infected person, despite them not being in their direct line of sight.

It would also affect how far away from the patient hard surfaces need cleaning and whether airborne personal protective equipment (PPE) precautions – such as P2 respirator masks – would need to be more widely used.

Our definition of “sufficient contact” for someone to be a possible new infection may broaden, which would mean more people need to be monitored, tested and possibly quarantined for each known patient.

But even if an airborne route is found in the future, it’s unlikely to be the major route of transmission.

People who are ill and show symptoms such as coughing and sneezing usually produce and expel viruses in greater amounts than those who show fewer symptoms. These sicker people are more likely to spread the virus via bigger wet droplets, physical contact and contamination of surfaces and objects.

Do I need to worry?

No. SARS-CoV-2 has been spreading the whole time, regardless of our understanding of how. That spread doesn’t look to be changing.

Currently, relatively few people infected with SARS-CoV-2 are outside of mainland China. Only 15 cases have been identified in Australia. Those found are isolated quickly and are well cared for.



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The chances of catching SARS-CoV-2 outside of mainland China are, at the moment, remote (provided you aren’t on a certain cruise ship).

If the situation changes because infected travellers arrive in greater numbers than we can contain, then our best tools to mitigate spread remain the ones we already know:

  • distancing ourselves from obviously ill people
  • hand-washing
  • cleaning surfaces
  • good cough etiquette (coughing into a tissue or your elbow and washing your hands)
  • keeping our hands away from our face.

And if you are at risk, stay home and seek medical advice by phone.The Conversation

Ian M. Mackay, Adjunct assistant professor, The University of Queensland and Katherine Arden, Virologist, The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.

How does poor air quality from bushfire smoke affect our health?

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Brian Oliver, University of Technology Sydney

New South Wales and Queensland are in the grip of a devastating bushfire emergency, which has tragically resulted in the loss of homes and lives.

But the smoke produced can affect many more people not immediately impacted by the fires – even people many kilometres from the fire. The smoke haze blanketing parts of NSW and Queensland has seen air quality indicators exceed national standards over recent days.

Studies have shown there is no safe level of air pollution, and as pollution levels increase, so too do the health risks. Air pollution caused nine million premature deaths globally in 2015. In many ways, airborne pollution is like cigarette smoking – causing respiratory disease, heart disease and stroke, lung infections, and even lung cancer.



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However, these are long-term studies looking at what happens over a person’s life with prolonged exposure to air pollution. With bushfire-related air pollution, air quality is reduced for relatively short periods.

But it’s still worth exercising caution if you live in an affected area, particularly if you have an existing health condition that might put you at higher risk.

Air quality standards

The exposure levels will vary widely from the site of the fire to 10 or 50 kilometres away from the source.

The national standard for clean air in Australia is less than 8 micrograms/m³ of ultrafine particles. This is among the lowest in the world, meaning the Australian government wants us to remain one of the least polluted countries there is.

8 micrograms/m³ refers to the weight of the particles in micrograms contained in one cubic meter of air. A typical grain of sand weighs 50 micrograms. When people talk about ultrafine particles the term PM, referring to particulate matter, is often used. The size of PM we worry the most about are the small particles of less than 2.5 micrometres which can penetrate deep into the lungs, called PM2.5.

People with pre-existing medical conditions are at highest risk.
From shutterstock.com

To put this in perspective, Randwick, a coastal suburb in Sydney which was more than 25km from any of the fires yesterday, had PM2.5 readings of around 40 micrograms/m³. Some suburbs which sit more inland had readings of around 50 micrograms/m³. Today, these levels have already reduced to around 20 micrograms/m³ across Sydney.

We’re seeing a similar effect in Queensland. Today’s PM2.5 readings at Cannon Hill, a suburb close to central Brisbane, are 21.5 micrograms/m³, compared with 4.7 micrograms/m³ one month ago.

A number of health alerts were issued for areas across NSW and Queensland earlier this week.

While these numbers may seem alarming compared to the 8 microgram/m³ threshold, the recent air pollution in India’s New Delhi caused by crop burning reached levels of 900 micrograms/m³. So what we’re experiencing here pales in comparison.

Bushfire smoke and our health

However, this doesn’t mean the levels in NSW and Queensland are without danger. Historically, when there are bushfires, emergency department presentations for respiratory and heart conditions increase, showing people with these conditions are most at risk of experiencing adverse health effects.

Preliminary analysis of emergency department data shows hospitals in the mid-north coast of NSW, where fires were at their worst, have had 68 presentations to emergency departments for asthma or breathing problems over the last week. This is almost double the usual number.



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One study looked at the association between exposure to smoke events in Sydney and premature deaths, and found there was a 5% increase in mortality during bushfires from 1994 to 2007.

But it’s important to understand these deaths would have occurred in the people most vulnerable to the effects of smoke, such as people with pre-exsisiting lung and heart conditions, who tend to be older people.

For people who are otherwise healthy, the health risks are much lower.

But as the frequency of bushfires increases, many scientists in the field speculate these health effects may become more of a concern across the population.

How to protect yourself

If you’re in an affected area, it’s best to avoid smoke exposure where possible by staying indoors with the windows and doors closed and the air conditioner turned on.

If you are experiencing any unusual symptoms, such as shortness of breath or chest pain, or just do not feel well, you should speak to your health care professional and in an emergency, go to hospital.



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Once the fires have been put out, depending upon the region, local weather conditions and the size of the fire, air quality can return to healthy levels within a few days.

In extreme situations, it might take weeks or months to return to normal. But we are fortunate to be living in a country with good air quality most of the time.The Conversation

Brian Oliver, Research Leader in Respiratory cellular and molecular biology at the Woolcock Institute of Medical Research and Senior Lecturer, School of Medical & Molecular Biosciences, University of Technology Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Our ability to manufacture minerals could transform the gem market, medical industries and even help suck carbon from the air

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Pictured is a slag pile at Broken Hill in New South Wales. Slag is a man-made waste product created during smelting.
Anita Parbhakar-Fox, Author provided

Anita Parbhakar-Fox, The University of Queensland and Paul Gow, The University of Queensland

Last month, scientists uncovered a mineral called Edscottite. Minerals are solid, naturally occurring substances that are not living, such as quartz or haematite. This new mineral was discovered after an examination of the Wedderburn Meteorite, a metallic-looking rock found in Central Victoria back in 1951.

Edscottite is made of iron and carbon, and was likely formed within the core of another planet. It’s a “true” mineral, meaning one which is naturally occurring and formed by geological processes either on Earth or in outer-space.

But while the Wedderburn Meteorite held the first-known discovery of Edscottite, other new mineral discoveries have been made on Earth, of substances formed as a result of human activities such as mining and mineral processing. These are called anthropogenic minerals.

While true minerals comprise the majority of the approximately 5,200 known minerals, there are about 208 human-made minerals which have been approved as minerals by the International Mineralogical Association.

Some are made on purpose and others are by-products. Either way, the ability to manufacture minerals has vast implications for the future of our rapidly growing population.

Modern-day alchemy

Climate change is one of the biggest challenges we face. While governments debate the future of coal-burning power stations, carbon dioxide continues to be released into the atmosphere. We need innovative strategies to capture it.

Actively manufacturing minerals such as nesquehonite is one possible approach. It has applications in building and construction, and making it requires removing carbon dioxide from the atmosphere.



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Nesquehonite occurs naturally when magnesian rocks slowly break down. It has been identified at the Paddy’s River mine in the Australian Capital Territory and locations in New South Wales.

But scientists discovered it can also be made by passing carbon dioxide into an alkaline solution and having it react with magnesium chloride or sodium carbonate/bicarbonate.

This is a growing area of research.

Other synthetic minerals such as hydrotalcite are produced when asbestos tailings passively absorb atmospheric carbon dioxide, as discovered by scientists at the Woodsreef asbestos mine in New South Wales.

You could say this is a kind of “modern-day alchemy” which, if taken advantage of, could be an effective way to suck carbon dioxide from the air at a large scale.

Meeting society’s metal demands

Mining and mineral processing is designed to recover metals from ore, which is a natural occurrence of rock or sediment containing sufficient minerals with economically important elements. But through mining and mineral processing, new minerals can also be created.

Smelting is used to produce a range of commodities such as lead, zinc and copper, by heating ore to high temperatures to produce pure metals.

The process also produces a glass-like waste product called slag, which is deposited as molten liquid, resembling lava.

This is a backscattered electron microscope image of historical slag collected from a Rio Tinto mine in Spain.
Image collected by Anita Parbhakar-Fox at the University of Tasmania (UTAS)

Once cooled, the textural and mineralogical similarities between lava and slag are crystal-clear.

Micro-scale inspection shows human-made minerals in slag have a unique ability to accommodate metals into their crystal lattice that would not be possible in nature.

This means metal recovery from mine waste (a potential secondary resource) could be an effective way to supplement society’s growing metal demands. The challenge lies in developing processes which are cost effective.



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Ethically-sourced jewellery

Our increasing knowledge on how to manufacture minerals may also have a major impact on the growing synthetic gem manufacturing industry.

In 2010, the world was awestruck by the engagement ring given to Duchess of Cambridge Kate Middleton, valued at about £300,000 (AUD$558,429).

The ring has a 12-carat blue sapphire, surrounded by 14 solitaire diamonds, with a setting made from 18-carat white gold.

Replicas of it have been acquired by people across the globe, but for only a fraction of the price. How?

In 1837, Marc Antoine Gardin demonstrated that sapphires (mineralogically known as corundum or aluminium oxide) can be replicated by reacting metals with other substances such as chromium or boric acid. This produces a range of seemingly identical coloured stones.

On close examination, some properties may vary such as the presence of flaws and air bubbles and the stone’s hardness. But only a gemologist or gem enthusiast would likely notice this.

Diamonds can also be synthetically made, through either a high pressure, high temperature, or chemical vapour deposition process.

Synthetic diamonds have essentially the same chemical composition, crystal structure and physical properties as natural diamonds.
Instytut Fizyki Uniwersytet Kazimierza Wielkiego

Creating synthetic gems is increasingly important as natural stones are becoming more difficult and expensive to source. In some countries, the rights of miners are also violated and this poses ethical concerns.

Medical and industrial applications

Synthetic gems have industrial applications too. They can be used in window manufacturing, semi-conducting circuits and cutting tools.

One example of an entirely manufactured mineral is something called yttrium aluminum garnet (or YAG) which can be used as a laser.

In medicine, these lasers are used to correct glaucoma. In dental surgery, they allow soft gum and tissues to be cut away.

The move to develop new minerals will also support technologies enabling deep space exploration through the creation of ‘quantum materials’.

Quantum materials have unique properties and will help us create a new generation of electronic products, which could have a significant impact on space travel technologies. Maybe this will allow us to one day visit the birthplace of Edscottite?



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In decades to come, the number of human-made minerals is set to increase. And as it does, so too does the opportunity to find new uses for them.

By expanding our ability to manufacture minerals, we could reduce pressure on existing resources and find new ways to tackle global challenges.The Conversation

Anita Parbhakar-Fox, Senior Research Fellow in Geometallurgy/Applied Geochemistry, The University of Queensland and Paul Gow, Principal Research Fellow, The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Australia to send naval and air assistance to protect Middle East sea lanes: Morrison

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Michelle Grattan, University of Canberra

Australia will commit a frigate, an aircraft and some headquarters staff to an American-led freedom of navigation operation in the Middle East.

Scott Morrison, announcing the long-expected commitment at a Canberra news conference on Wednesday, stressed this was an international mission, but so far the United Kingdom is the only other country to have signed up.

Under questioning, the Chief of the Australian Defence Force, General Angus Campbell, said the operation would be United States-led. But Campbell avoided spelling out in detail the rules of engagement in the event of being involved in an incident, other than referring to legal obligations.

Iran has seized ships in recent months, amid escalating tensions.

This week, an Iranian oil tanker was released after being detained by the British overseas territory of Gibraltar on suspicion of taking oil to Syria. The US tried unsuccessfully to have Gibraltar extend the vessel’s detention.

Morrison said Australia had made very clear both to the US and the UK “that we are here as part of a multinational effort”.

“This is a modest, meaningful and time-limited contribution …to this international effort to ensure we maintain free-flow of commerce and of navigation,” he said.

“Australia will defend our interests, wherever they may be under threat, we will always work closely with our international allies and partners.”



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Morrison emphasised that the safety of shipping lanes was vital to Australia’s economic interests.

The government had been concerned over incidents in the Strait of Hormuz, he said. “30% of refined oil destined for Australia travels through the Strait. It is a threat to our economy.”

The Australian contribution will be

  • a P-8A Poseidon maritime surveillance aircraft for one month before the end of 2019;

  • an Australian frigate in January 2020 for six months; and

  • ADF personnel to the International Maritime Security Construct headquarters in Bahrain.

One complication for Australia in finalising the commitment was the fact there was no Australian frigate in the area, with the next deployment not due until January.

Australian ships participate in counter-piracy and counter-terrorism operations in the Middle East.

The Americans were very pressing in their request to Australia to join the force, including in public statements during the recent AUSMIN talks.

Morrison has emphasised Australia wants to see the de-escalation of tensions in the area and separates its commitment to the freedom of navigation operation from America’s other activities in relation to Iran.The Conversation

Michelle Grattan, Professorial Fellow, University of Canberra

This article is republished from The Conversation under a Creative Commons license. Read the original article.

China: The J-20 Fighter

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The link below is to an article reporting on China’s J-20 Fighter, which marks an interesting development for air defence throughout the world.

For more visit:
https://medium.com/editors-picks/e7dd4741d89f

Australia: Defence – The F-35

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The F-35 Joint Strike Fighter is central to Australia’s air defence plans for the years ahead, however, the continuing delays are causing major issues for Australia’s current defence needs. The link below is to an article that examines the F-35 development program in some detail.

For more visit:
http://www.latimes.com/business/la-fi-0612-fighter-jet-testing-20130612-dto,0,4701367.htmlstory

Syria: Israel Attacks Weapons Convoy Bound for Hezbollah

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The link below is to an article reporting on the latest news concerning Israeli air strikes against a weapons convoy in Syria bound for Hezbollah in Lebanon.

For more visit:
http://www.guardian.co.uk/world/2013/may/04/israel-syria-weapons-lebanon