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Melting Greenland ice now source of 25% of sea level rise, researchers say

Ocean levels rose 50 percent faster in 2014 than in 1993, with meltwater from the Greenland ice sheet now supplying 25 percent of total sea level increase compared with just 5 percent 20 years earlier, researchers reported Monday.

http://www.japantimes.co.jp/news/2017/06/27/world/science-health-world/melting-greenland-ice-now-source-25-sea-level-rise-researchers-say/#.WVWU6YiGOHs

The findings add to growing concern among scientists that the global watermark is climbing more rapidly than forecast only a few years ago, with potentially devastating consequences.

Hundreds of millions of people around the world live in low-lying deltas that are vulnerable, especially when rising seas are combined with land sinking due to depleted water tables, or a lack of ground-forming silt held back by dams.

Major coastal cities are also threatened, while some small island states are already laying plans for the day their drowning nations will no longer be livable.

“This result is important because the Intergovernmental Panel on Climate Change (IPCC)” — the U.N. science advisory body — “makes a very conservative projection of total sea level rise by the end of the century,” at 60 to 90 cm (24 to 35 inches), said Peter Wadhams, a professor of ocean physics at the University of Oxford who did not take part in the research.

That estimate, he added, assumes that the rate at which ocean levels rise will remain constant.

“Yet there is convincing evidence — including accelerating losses of mass from Greenland and Antarctica — that the rate is actually increasing, and increasing exponentially.”

Greenland alone contains enough frozen water to lift oceans by about 7 meters (23 feet), though experts disagree on the global warming threshold for irreversible melting, and how long that would take once set in motion.

“Most scientists now expect total rise to be well over a meter by the end of the century,” Wadhams said.

The new study, published in Nature Climate Change, reconciles for the first time two distinct measurements of sea level rise.

The first looked one-by-one at three contributions: ocean expansion due to warming, changes in the amount of water stored on land, and loss of land-based ice from glaciers and ice sheets in Greenland and Antarctica.

The second was from satellite altimetry, which gauges heights on the Earth’s surface from space.

The technique measures the time taken by a radar pulse to travel from a satellite antenna to the surface, and then back to a satellite receiver.

Up to now, altimetry data showed little change in sea levels over the last two decades, even if other measurements left little doubt that oceans were measurably deepening.

“We corrected for a small but significant bias in the first decade of the satellite record,” co-author Xuebin Zhang, a professor at Qingdao National Laboratory of Marine Science and Technology in China’s Shandong Province, told AFP.

Overall, the pace of global average sea level rise went up from about 2.2 mm a year in 1993, to 3.3 mm a year two decades later.

In the early 1990s, they found, thermal expansion accounted for fully half of the added millimeters. Two decades later, that figure was only 30 percent.

Andrew Shepherd, director of the Centre for Polar Observation and Modelling at the University of Leeds in England, urged caution in interpreting the results.

“Even with decades of measurements, it is hard to be sure whether there has been a steady acceleration in the rate of global sea level rise during the satellite era because the change is so small,” he said.

Disentangling single sources — such as the massive chunk of ice atop Greenland — is even harder.

But other researchers said the study should sound an alarm.

“This is a major warning about the dangers of a sea level rise that will continue for many centuries, even after global warming is stopped,” said Brian Hoskins, chair of the Grantham Institute at Imperial College London.

New study confirms the oceans are warming rapidly

Although there’s some uncertainty in the distribution among Earth’s ocean basins, there’s no question that the ocean is heating rapidly

As humans put ever more heat-trapping gases into the atmosphere, the Earth heats up. These are the basics of global warming. But where does the heat go? How much extra heat is there? And how accurate are our measurements? These are questions that climate scientists ask. If we can answer these questions, it will better help us prepare for a future with a very different climate. It will also better help us predict what that future climate will be.

The most important measurement of global warming is in the oceans. In fact, “global warming” is really “ocean warming.” If you are going to measure the changing climate of the oceans, you need to have many sensors spread out across the globe that take measurements from the ocean surface to the very depths of the waters. Importantly, you need to have measurements that span decades so a long-term trend can be established.

These difficulties are tackled by oceanographers, and a significant advancement was presented in a paper just published in the journal Climate Dynamics. That paper, which I was fortunate to be involved with, looked at three different ocean temperature measurements made by three different groups. We found that regardless of whose data was used or where the data was gathered, the oceans are warming.

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In the paper, we describe perhaps the three most important factors that affect ocean-temperature accuracy. First, sensors can have biases (they can be “hot” or “cold”), and these biases can change over time. An example of biases was identified in the 1940s. Then, many ocean temperature measurements were made using buckets that gathered water from ships. Sensors put into the buckets would give the water temperature. Then, a new temperature sensing approach started to come online where temperatures were measured using ship hull-based sensors at engine intake ports. It turns out that bucket measurements are slightly cooler than measurements made using hull sensors, which are closer to the engine of the ship.

During World War II, the British Navy cut back on its measurements (using buckets) and the US Navy expanded its measurements (using hull sensors); consequently, a sharp warming in oceans was seen in the data. But this warming was an artifact of the change from buckets to hull sensors. After the war, when the British fleet re-expanded its bucket measurements, the ocean temperatures seemed to fall a bit. Again, this was an artifact from the data collection. Other such biases and artifacts arose throughout the years as oceanographers have updated measurement equipment. If you want the true rate of ocean temperature change, you have to remove these biases.

Another source of uncertainty is related to the fact that we just don’t have sensors at all ocean locations and at all times. Some sensors, which are dropped from cargo ships, are densely located along major shipping routes. Other sensors, dropped from research vessels, are also confined to specific locations across the globe.

Currently, we are heavily using the ARGO fleet, which contains approximately 3800 autonomous devices spread out more or less uniformly across the ocean, but these only entered service in 2005. Prior to that, temperatures measurements were not uniform in the oceans. As a consequence, scientists have to use what is called a “mapping” procedure to interpolate temperatures between temperature measurements. Sort of like filling in the gaps where no data exist. The mapping strategy used by scientists can affect the ocean temperature measurements.

Finally, temperatures are usually referenced to a baseline “climatology.” So, when we say temperatures have increased by 1 degree, it is important to say what the baseline climatology is. Have temperatures increased by 1 degree since the year 1990? Since the year 1970? Since 1900? The choice of baseline climatology really matters.

In the study, we looked at the different ways that three groups make decisions about mapping, bias, and climatology. We not only asked how much the oceans are warming, but how the warming differs for various areas (ocean basins) and various depths. We found that each ocean basin has warmed significantly. Despite this fact, there are some differences amongst the three groups. For instance, in the 300-700 meter oceans depths in the Pacific and Southern oceans, significant differences are exhibited amongst the tree groups. That said, the central fact is that regardless of how you measure, who does the measurements, when or where the measurements are taken, we are warming.

The lead author, Dr. Gonjgie Wang described the importance of the study this way:

Our study confirms again a robust global ocean warming since 1970. However, there is substantial uncertainty in decadal scale ocean heat redistribution, which explains the contradictory results related to the ocean heat changes during the “slowdown” of global warming in recent decade. Therefore, we recommend a comprehensive evaluation in the future for the existing ocean subsurface temperature datasets. Further, an improved ocean observation network is required to monitor the ocean change: extending the observations in the boundary currents systems and deep oceans (below 2000-m) besides maintaining the Argo network.

In plain English, it will be important that we keep high-quality temperature sensors positioned throughout the oceans so in the future we will be able to predict where our climate is headed. We say in science that a measurement not made is a measurement lost forever. And there are no more important measurements than of heating of the oceans.

Exposure to pollution in Hong Kong is worst in the home, study reveals

It’s not just on the city’s streets where we are at risk from dangerous PM2.5 particulates – three-quarters of daily personal exposure is indoors

http://www.scmp.com/news/hong-kong/health-environment/article/2097540/exposure-pollution-hong-kong-worst-home-study

Your home may be your refuge in Hong Kong, but not from air pollution. It’s probably worse.

Exposure to PM2.5 particulates small enough to lodge deep in the lungs and most harmful to human health have been found to be just as high – or higher – inside people’s homes as they are outdoors or during the commute to work on an average weekday.

A two-year study by think tank Civic Exchange and City University, funded by investment bank Morgan Stanley, found that most urban dwellers are exposed to concentrations of PM2.5 during their daily commute that are almost always above average limits set by the World Health Organisation, and generally above readings at the nearest air quality monitoring station.

Breathe easier, Hong Kong is on course to hit global air pollution target

While the Environmental Protection Department’s 16 stations can monitor and assess ambient and roadside air quality across districts, the study fills a relatively wide gap in statistics on individual-level exposure to pollution in different “micro-environments”.

Co-author Dr Zhi Ning reported finding that people were exposed to air pollution risks not just outdoors but also indoors at home or the office.

“Your 24 hours are spent in different environments,” the City University air pollution expert said. “You may think that even if its very polluted outside, you are more safe inside. But it really depends on what that indoor environment is like.”

The researchers employed 73 volunteers who carried lunchbox-sized “personal exposure kits” fitted with sensors and GPS, 24 hours a day for a year around the city.

They found that most spent more than 85 per cent of each weekday indoors, which broke down to 42 per cent of the day at home, 34 per cent in the office, 4 per cent commuting and 11 per cent outdoors or in other indoor areas.

Homes were found to contribute 52 per cent of an individual’s personal exposure to PM2.5 compared with 13 per cent for offices, 4 per cent while commuting, 18 per cent outdoors and 14 per cent in other indoor areas.

The average PM2.5 concentration measured in homes – 42.5 micrograms per cubic metre – was three to four times lower than outdoors but slightly higher than while commuting and three times higher than in the office.

Factors for the PM2.5 build up in homes, Ning surmised, could range from cooking and the type of gas used to proximity to a construction site or smoking tobacco. And this was exacerbated by poor ventilation and dirty air filters. Offices tended to have better ventilation systems. Flats on lower floors were also exposed to more pollution.

But Ning found little correlation between personal exposure and district pollution. A person who spent more time in better ventilated indoor areas in heavily polluted Sham Shui Po, for example, could have a lower exposure to PM2.5 than the station reading and vice versa.

“Right now we only rely on [the department’s] data but they only provide a general, ballpark figure,” Civic Exchange research fellow and co-author Simon Ng Ka-wing said.

“It is important to know how much air pollution we are exposed to on a personal level. This would allow us to make better decisions as to when to go or not to go somewhere.”

The study recommended the government do more to promote better indoor air quality in homes and implement a comprehensive management programme.

A government spokesman said: “The EPD has been conducting promotional and educational activities, including exhibitions and seminars, to promote practices to achieve good indoor air quality.”

Additional reporting by Brian Wong

Fasten your seat belts: Climate change could add to turbulence during air travel

Flight turbulence could increase significantly under climate change, a study warns, potentially upping the risk of injury — or at least flight anxiety — for future airline passengers. Furthermore, fuel and maintenance costs for carriers could rise.

http://www.bendbulletin.com/nation/5214806-151/fasten-your-seat-belts-climate-change-could-add

An increase in atmospheric carbon dioxide concentrations could cause changes in the jet stream over the North Atlantic flight corridor, leading to a spike in air turbulence, suggests the research conducted by atmospheric scientist Paul Williams of the University of Reading.

By the middle of the century, with no effort to reduce atmospheric concentrations of carbon dioxide, the volume of airspace experiencing light turbulence would increase by about 59 percent.

Airspace experiencing severe turbulence could increase by anywhere from 36 percent to 188 percent, the study found.

“We’re particularly interested in severe turbulence, because that’s the kind of turbulence that’s strong enough to hospitalize people,” Williams told The Washington Post.

Forecasting algorithms can help pilots anticipate and avoid turbulent patches. But the research does suggest that future fliers could be in for a bumpier ride.

The paper builds on a 2013 study in the journal Nature Climate Change by Williams and colleague Manoj Joshi of the University of East Anglia, which found an increase in moderate-to-severe turbulence in the North Atlantic as a result of climate change.

The study did not investigate the effects on lighter or more severe degrees of turbulence. In the new paper, Williams expanded the study to light turbulence, and more severe conditions.

Light turbulence typically comes with only minor discomfort for passengers, perhaps an increase in nausea or anxiety. Severe turbulence has been known to cause injuries and even hospitalizations.

Williams focused on an area in the North Atlantic known for heavy air traffic, particularly between Europe and North America, and limited his simulations to winter, when turbulence is known to be at its highest.

He examined 21 different wind-related characteristics known to be indicators of air turbulence levels, including wind speed and changes in air flow direction.

The study found an increase in turbulence across the spectrum. Light turbulence was projected to increase by an average of 59 percent, light-to-moderate by 75 percent, moderate by 94 percent, moderate-to-severe by 127 percent and severe by 149 percent, although there’s substantial uncertainty associated with the more severe categories.

Williams stressed that severe turbulence would remain rare — even with the increase. But even an increase in light turbulence can cause greater wear and tear on planes or force pilots to use extra fuel redirecting their flight paths to avoid rough patches.

The increase in air turbulence may apply only to the North Atlantic, researchers not involved in the study said.

“Regional variations of this increase may be quite uncertain, particularly in the higher latitudes where other aspects of circulation change that are less well understood and more model-dependent may dominate,” said Isla Simpson, a scientist at the National Center for Atmospheric Research, in an emailed comment to The Post.

Kristopher Karnauskas, an atmospheric and oceanic sciences expert at the University of Colorado at Boulder, said the behavior of the jet stream over the Pacific may respond differently to climate change.

The study builds on an area of climate science that increasingly suggests rising global temperatures can cause changes in atmospheric airflow, including shifts in major air currents known as jet streams.

Because the equator is the warmest part of the planet, and warm air takes up more space than cold air, the atmosphere tends to be thicker around the center of Earth than at the poles. As a result, there’s a kind of downhill atmospheric slope from the equator to the poles over which air flows. While this is happening, Earth is constantly spinning, pushing airflow eastward. In the North Atlantic, the result is a jet stream — a meandering, wavy current flowing around the planet from west to east.

As the planet grows hotter, however, warming air near the surface could bring about changes in the atmospheric slope between equator and poles. Models such as the one used in Williams’ new paper have suggested that the jet stream could become stronger as a result, bringing about an increase in the types of wind patterns that lead to increased air turbulence.

Some research has already begun to detect changes in large-scale atmospheric currents. Other scientists have suggested that rapid warming in the Arctic is actually causing the jet stream to weaken.

There remains considerable uncertainty about how airflow near Earth’s surface might change in the future, Simpson said. But she said scientists are becoming more confident about the changes “that we expect to happen higher up, near the altitude where planes fly.”

Examining these issues can lead to a better understanding of the effects of climate change on aviation, Karnauskas said.

“I think it’s been decades that all of the attention has been on the impact of such industries like aviation on climate, but this is something that’s flipping it around and looking at the impact of climate on aviation,” he said. “If we can really understand the two-way street that we’re dealing with, that’s really going to help us understand ultimately how the climate will change in the future as a coupled system between the people and the atmosphere.”

Arctic sea ice, Eurasia snow, and extreme winter haze in China

Download (PDF, 773KB)

Lung disease costs the United Kingdom £11bn every year – report

https://uk.news.yahoo.com/lung-disease-costs-united-kingdom-11bn-every-report-015300294.html

New figures show lung disease is costing the UK more than £11bn every year, prompting criticism the NHS and governments are not doing enough to tackle one of the country’s biggest killers.

A report by the British Lung Foundation (BLF) says, despite such a large healthcare bill for respiratory conditions, there has been little change in mortality rates over the last 10 years.

The Foundation says 115,000 people die from lung disease every year – one person every five minutes.

More than 12 million people are living with a lung condition in the UK.

It also claims the UK has the highest mortality rates for children with asthma in Europe.

According to the BLF, of the £11.1bn that lung disease costs every year, £9.9bn is spent by the NHS.

A further £1.2bn is lost in the wider economy through things like days off work.

There are calls for the governments and NHS in both England and Scotland to create special taskforces for lung health, and produce new five-year strategies for tackling lung disease.

Dr Nicholas Hopkinson, Medical Adviser for the British Lung Foundation, told Sky News air pollution is a major part of the problem.

He said: “In this country, the estimate from the Royal College of Physicians is that there are about 40,000 excess deaths per year caused by air pollution and one of the things in parallel with a respiratory task-force would be a new Clean Air Act.

“We need for the Government to be setting strong binding targets and actions to reduce this air quality problem.”

At the Hospice of St Francis in Hertfordshire, a group of patients with pulmonary fibrosis take part in a fortnightly exercise group.

Their condition will get worse. Some will take years to deteriorate and others will worsen more quickly.

One of the patients, Peter Bryce, runs the Pulmonary Fibrosis Trust. He told Sky News groups like his offer vital support.

“Coming here is like joining a family. The people understand the nature of this illness and it’s easy to relate to them and share experiences and support each other. It’s brilliant,” he said.

The Hospice only receives 20% of its funding from the NHS – but it is this sort of support group campaigners want to see more of to help those with lung conditions.

The Department of Health insists it is doing more to tackle lung conditions.

A DoH spokesperson told Sky News: “It is plainly wrong to suggest that tackling lung disease is not a priority – government research funding has risen to over £25 million, our policies have helped reduce smoking rates to a record low and Public Health England has extended its successful ‘Be Clear on Cancer’ campaign to raise awareness of the symptoms.”

India reported 1.1 million deaths due to air pollution in 2015, says a global study

http://economictimes.indiatimes.com/news/environment/pollution/india-reported-1-1-million-deaths-due-to-air-pollution-in-2015-says-a-global-study/printarticle/57145119.cms

The government here may be in denial mode on linking premature deaths to air pollution, but a new study on global air pollution by the US-based institutes claims that the India’s worsening air pollution caused some 1.1 million premature deaths in 2015 and the country now “rivals China for among the highest air pollution health burdens in the world.”

The special report on ‘global exposure to air pollution and its disease burden’, released on Tuesday, noted that the number of premature deaths in China caused by dangerous fine particulate matter, known as PM2.5, has stabilised in recent years but has risen sharply in India.

It also said that both the countries together were responsible for over half of the total global attributable deaths while India had registered an alarming increase of nearly 50% in premature deaths from particulate matter between 1990 and 2015.

Besides data analysis on air pollution, the report also carries an interactive website on the issue highlighting that 92% of the world’s population lives in the areas with unhealthy air.

“We are seeing increasing air pollution problems worldwide, and this new report and website details why that air pollution is a major contributor to early death,” said Dan Greenbaum, President of the Health Effects Institute (HEI), the global research institute that designed and implemented the study.

He said, “The trends we report show that we have seen progress in some parts of the world – but serious challenges remain.”

The State of Global Air 2017 is the first of a new series of annual reports and accompanying interactive website, designed and implemented by the Health Effects Institute in cooperation with the Institute of Health Metrics and Evaluation (IHME) at the University of Washington and the University of British Columbia.

The IHME is an independent population health research center that publishes the annual Global Burden of Diseases — a systematic scientific effort to quantify the magnitude of health loss from all major diseases, injuries, and risk factors in populations across the world. Its results are published every year in The Lancet medical journal.

“Although there are many parts of the world where air pollution has grown worse, there has also been improvement in the US and Europe. The US Clean Air Act and actions by the European Commission have made substantial progress in reducing people exposed to PM pollution since 1990,” said a statement issued by the HEI.

Referring to the study, it said, “The US has experienced a reduction of about 27% in average annual population exposures to fine particulate matter with smaller declines in Europe. Yet some 88,000 Americans and 258,000 Europeans still face increased risks of dying early due to PM levels today”.

The report noted that the highest concentrations of combustion-related fine particulate matter were in South and Southeast Asia, China and Central and Western Sub-Saharan Africa in 2015 where household solid fuel use, coal-fired power plants, transportation, and open burning of agricultural and other wastes were among the most important contributors to outdoor air pollution.

“The Global Burden of Disease leads a growing worldwide consensus – among the WHO, World Bank, International Energy Agency and others – that air pollution poses a major global public health challenges,” said Bob O’Keefe, Vice President of HEI and Chair of Clean Air Asia.

He said, “Nowhere is that risk more evident than in the rapidly growing economies of Asia.”

The study finds that increasing exposure and a growing and aging population have meant that India now rivals China for among the highest air pollution health burdens in the world, with both countries facing some 1.1 million early deaths from air pollution in 2015.

It said the long-term exposure to fine particulate matter — the most significant element of air pollution — contributed to 4.2 million premature deaths and to a loss of 103 million healthy years of life in 2015, making air pollution the 5th highest cause of death among all health risks, including smoking, diet, and high blood pressure.

India has, however, always been sceptical of such reports. Though the government here did never deny the negative impact of air pollution on human healths, it preferred not to speak about numbers.

Even recently during Budget session of the Parliament, the government had on February 6 said that there was no conclusive data to link deaths exclusively with air pollution. It, however, admitted that the air pollution could be one of the triggering factors for respiratory ailments and diseases.

“There is no conclusive data available in the country to establish direct co-relationship of death exclusively with air pollution. Health effects of air pollution are synergistic manifestation of factors which include food habits, occupational habits, socio-economic status, medical history, immunity, heredity etc. of the individuals,” said the country’s environment minister Anil Madhav Dave.

Dave, in his written response to a Parliament question in Rajya Sabha, had said, “Air pollution could be one of the triggering factors for respiratory associated ailments and diseases.”

Tube ‘higher than driving’ for air pollution, study finds

Travelling on the Underground exposes commuters to more than eight times as much air pollution as those who drive to work, a university study has found.

Monitors worn by commuters found those who travelled on the Tube were exposed to 68mg of harmful pollutant PM10, whereas car drivers had 8.2mg.

The University of Surrey study found when train windows were open, commuters were exposed to more pollutants.

Drivers were not as exposed because cars filter the pollutants out.

But although drivers are not exposed to as many pollutants, the types given out by cars are more harmful than the ones found on the Underground.

‘Environmental injustice’

The study found PM levels were highest on trains on the Victoria and Northern lines, because they all had their windows open, heightening the effect of pollutants when going through tunnels.

The study did not include people who commute on foot or cycle.

The study also found:

• Passengers on the District Line in trains with closed windows were exposed to far lower concentrations of PM than those travelling on trains with open windows on the same line
• Bus commuters were exposed to an average of 38mg of PM10, roughly half as much as Tube passengers but five times as much as cars
• The morning commute has more pollutants than the afternoon and evening journeys
• Although car drivers were the least exposed, they caused the most pollutants.

Dr Prashant Kumar, who led the study, said: “We found that there is definitely an element of environmental injustice among those commuting in London, with those who create the most pollution having the least exposure to it.

“The relatively new airtight trains with closed windows showed a significant difference to the levels of particles people are exposed to over time, suggesting that operators should consider this aspect during any upgrade of Underground trains, along with the ways to improve ventilation in underground tunnels.”

The surprising link between air pollution and Alzheimer’s disease

http://www.latimes.com/science/sciencenow/la-sci-sn-air-pollution-alzheimers-20170131-story.html

With environmental regulations expected to come under heavy fire from the Trump administration, new research offers powerful evidence of a link between air pollution and dementia risk.

For older women, breathing air that is heavily polluted by vehicle exhaust and other sources of fine particulates nearly doubles the likelihood of developing dementia, finds a study published Tuesday. And the cognitive effects of air pollution are dramatically more pronounced in women who carry a genetic variant, known as APOE-e4, which puts them at higher risk for developing Alzheimer’s disease.

In a nationwide study that tracked the cognitive health of women between the ages of 65 and 79 for 10 years, those who had the APOE-e4 variant were nearly three times more likely to develop dementia if they were exposed to high levels of air pollution than APOE-e4 carriers who were not.

Among carriers of that gene, older women exposed to heavy air pollution were close to four times likelier than those who breathed mostly clean air to develop “global cognitive decline” — a measurable loss of memory and reasoning skills short of dementia.

While scientists have long tallied the health costs of air pollution in asthma, lung disease and cardiovascular disease, the impact of air pollutants on brain health has only begun to come to light. This study gleans new insights into how, and how powerfully, a key component of urban smog scrambles the aging brain.

Published Tuesday in the journal Translational Psychiatry, the research looks at a large population of American women, at lab mice, and at brain tissue in petri dishes to establish a link between serious cognitive decline and the very fine particles of pollution emitted by motor vehicles, power plants and the burning of biomass products such as wood.

All three of these biomedical research methods suggest that exposure to high levels of fine air pollutants increases both dementia’s classic behavioral signs of disorientation and memory loss as well as its less obvious hallmarks. These include amyloid beta protein clumps in the brain and the die-off of cells in the brain’s hippocampus, a key center for memory formation.

Using air pollution standards set by the U.S. Environmental Protection Agency, researchers found significant differences on all those measures between those who breathed clean air and those exposed to pollution levels deemed unsafe.

In lab mice, breathing air collected over the 10 Freeway in Los Angeles led to brain concentrations of amyloid protein that were more dense and more likely to form dangerous clumps than breathing air that satisfied EPA standards before 2012. When lab mice were bred with a strong predisposition to develop dementia and its hallmarks, the brain differences between pollution-breathing animals and those that breathed clean air were starker.

In 2011, a study in the journal Lancet found that those who lived close to densely trafficked roads were at a far higher risk of stroke and dementia than those who lived farther away. A year later, a team led by Alzheimer’s disease researcher Dr. Samuel Gandy at Mt. Sinai in New York first established that air pollutants induced inflammation, cell death and the buildup of amyloid protein in the brains of mice.

The new study extends those findings.

Authored by geriatric and environmental health specialists at USC, the new study estimates that before the EPA set new air pollution standards in 2012, some 21% of new cases of dementia and of accelerated cognitive decline could likely have been attributed to air pollution.

There is potential legal significance to the researchers’ finding that women (and mice) who carried a genetic predisposition to developing Alzheimer’s disease were far more sensitive to air pollution’s effects. In devising pollution standards, the EPA is currently required to consider their health impact on “vulnerable populations.” The agency is also required to use its regulatory authority to take steps to protect those populations.

Air pollution has been declining steadily since the EPA promulgated new standards in 2012. But Dr. Jiu-Chiuan Chen, an environmental health specialist at USC’s Keck School of Medicine and the study’s senior author, said it’s not clear that even current standards are safe for aging brains, or for brains that are genetically vulnerable to Alzheimer’s.

The Trump administration has signaled it will look to scrap or substantially rewrite Obama administration regulations that tightened emissions from power plants and established tougher fuel efficiency standards for cars in an effort to curb climate change and reduce air pollution.

“If people in the current administration are trying to reduce the cost of treating diseases, including dementia, then they should know that relaxing the Clean Air Act regulations will do the opposite,” Chen said.

Dementia rates ‘higher near busy roads’

People who live near major roads have higher rates of dementia, research published in the Lancet suggests.

http://www.bbc.com/news/health-38506735

About 10% of dementia cases in people living within 50m of a major road could be down to traffic, the study suggests.

The researchers, who followed nearly 2m people in Canada over 11 years, say air pollution or noisy traffic could be contributing to the brain’s decline.

Dementia experts in the UK said the findings needed further investigation but were “certainly plausible”.

Nearly 50 million people around the world have dementia.

However, the causes of the disease, that robs people of their memories and brain power, are not understood.

Population growth

The study in the Lancet followed nearly two million people in the Canadian province of Ontario, between 2001 and 2012.

There were 243,611 cases of dementia diagnosed during that time, but the risk was greatest in those living closest to major roads.

Compared with those living 300m away from a major road the risk was:

• 7% higher within 50m
• 4% higher between 50-100m
• 2% higher between 101-200m

The analysis suggests 7-11% of dementia cases within 50m of a major road could be caused by traffic.

Dr Hong Chen, from Public Health Ontario and one of the report authors, said: “Increasing population growth and urbanisation have placed many people close to heavy traffic, and with widespread exposure to traffic and growing rates of dementia, even a modest effect from near-road exposure could pose a large public health burden.

“More research to understand this link is needed, particularly into the effects of different aspects of traffic, such as air pollutants and noise.”

The researchers suggest noise, ultrafine particles, nitrogen oxides and particles from tyre-wear may be involved.

However, the study looks only at where people diagnosed with dementia live. It cannot prove that the roads are causing the disease.

‘Provocative’

“This is an important paper,” says Prof Martin Rossor, the UK’s National Institute for Health Research director for dementia research.

He added: “The effects are small, but with a disorder with a high population prevalence, such effects can have important public health implications.”

Prof Tom Dening, the director of the Centre for Dementia at the University of Nottingham, said the findings were “interesting and provocative”.

He said: “It is certainly plausible that air pollution from motor exhaust fumes may contribute to brain pathology that over time may increase the risk of dementia, and this evidence will add to the unease of people who live in areas of high traffic concentration.

“Undoubtedly living in conditions of severe air pollution is extremely unpleasant and it is hard to suppose that it is good for anyone.”

The best advice to reduce the risk of dementia is to do the things that we know are healthy for the rest of the body – stop smoking, exercise and eat healthily.