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Air Pollution

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

‘Forest Cities’: The Visionary Plan to Save China From Air Pollution

Stefano Boeri, the architect famous for his plant-covered skyscrapers, has designs to create entire new green settlements in a nation plagued by dirty air

http://readersupportednews.org/news-section2/318-66/42061-forest-cities-the-visionary-plan-to-save-china-from-air-pollution

Nanjing Green Towers, promoted by Nanjing Yang Zi State-owned National Investment Group Co., Ltd, will be the first Vertical Forest built in Asia. (photo: Stefano Boeri Architetti)

Nanjing Green Towers, promoted by Nanjing Yang Zi State-owned National Investment Group Co., Ltd, will be the first Vertical Forest built in Asia. (photo: Stefano Boeri Architetti)

hen Stefano Boeri imagines the future of urban China he sees green, and lots of it. Office blocks, homes and hotels decked from top to toe in a verdant blaze of shrubbery and plant life; a breath of fresh air for metropolises that are choking on a toxic diet of fumes and dust.

Last week, the Italian architect, famed for his tree-clad Bosco Verticale (Vertical Forest) skyscraper complex in Milan, unveiled plans for a similar project in the eastern Chinese city of Nanjing.

The Chinese equivalent – Boeri’s first in Asia – will be composed of two neighbouring towers coated with 23 species of tree and more than 2,500 cascading shrubs. The structures will reportedly house offices, a 247-room luxury hotel, a museum and even a green architecture school, and are currently under construction, set for completion next year.

But Boeri now has even bolder plans for China: to create entire “forest cities” in a country that has become synonymous with environmental degradation and smog.

“We have been asked to design an entire city where you don’t only have one tall building but you have 100 or 200 buildings of different sizes, all with trees and plants on the facades,” Boeri told the Guardian. “We are working very seriously on designing all the different buildings. I think they will start to build at the end of this year. By 2020 we could imagine having the first forest city in China.”

Boeri described his “vertical forest” concept as the architectural equivalent of a skin graft, a targeted intervention designed to bring new life to a small corner of China’s polluted urban sprawl. His Milan-based practice claimed the buildings would suck 25 tons of carbon dioxide from Nanjing’s air each year and produce about 60 kg of oxygen every day.

“It is positive because the presence of such a large number of plants, trees and shrubs is contributing to the cleaning of the air, contributing to absorbing CO2 and producing oxygen,’ the architect said. “And what is so important is that this large presence of plants is an amazing contribution in terms of absorbing the dust produced by urban traffic.”

Boeri said, though, that it would take more than a pair of tree-covered skyscrapers to solve China’s notorious pollution crisis.

“Two towers in a huge urban environment [such as Nanjing] is so, so small a contribution – but it is an example. We hope that this model of green architecture can be repeated and copied and replicated.”

If the Nanjing project is a skin graft, Boeri’s blueprints for “forest cities” are more like an organ transplant. The Milan-born architect said his idea was to create a series of sustainable mini-cities that could provide a green roadmap for the future of urban China.

The first such settlement will be located in Luizhou, a mid-sized Chinese city of about 1.5 million residents in the mountainous southern province of Guangxi. More improbably, a second project is being conceived around Shijiazhuang, an industrial hub in northern China that is consistently among the country’s 10 most polluted cities.

Compared with the vertical forests, these blueprints represent “something more serious in terms of a contribution to changing the environmental urban conditions in China,” Boeri said.

Boeri, 60, first came to China in 1979. Five years ago he opened an office in Shanghai, where he leads a research program at the city’s Tongji University.

The architect said believed Chinese officials were finally understanding that they needed to embrace a new, more sustainable model of urban planning that involved not “huge megalopolises” but settlements of 100,000 people or fewer that were entirely constructed of “green architecture”.

“What they have done until now is simply to continue to add new peripheral environments to their cities,” he said. “They have created these nightmares – immense metropolitan environments. They have to imagine a new model of city that is not about extending and expanding but a system of small, green cities.”

Boeri described the idea behind his shrub-shrouded structures as simple, not spectacular: “What is spectacular is the nature, the idea of having a building that changes colour with each season. The plants and trees are growing and they are completely changing.”

“We think – and we hope – that this idea of vertical forests can be replicated everywhere. I absolutely have no problem if there are people who are copying or replicating. I hope that what we have done can be useful for other kinds of experiments.”

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.”

Drop in roadside air pollutants in Hong Kong thanks to government measures

I refer to Natalie Siu Hoi-tung’s letter on pollution in Hong Kong (“Air pollution impact can’t be ignored [1]”, January 27).

We can’t agree more that air pollution must not be ignored. The government has been taking action to improve air quality.

Locally, we have capped the emissions of power plants via statutory technical memorandums (TM) since 2008 and have been progressively tightening the caps. Since 2014, we have implemented an incentive-cum-regulatory scheme to progressively phase out 82,000 pre-Euro IV diesel commercial vehicles by the end of 2019.

We have also deployed remote sensors to strengthen emission control for petrol and liquefied petroleum gas vehicles.

In July 2015, Hong Kong became the first Asian city to mandate ocean-going vessels at berth to switch to low-sulphur fuel. A new regulation was introduced in June 2015 requiring newly imported non-road mobile machinery to comply with statutory emission standards.

Regionally, we have been collaborating with the mainland authorities to reduce emissions in the whole Pearl River Delta region. Emission reduction targets have been set for key air pollutants for 2015 and 2020.

Joint efforts have been made in various scientific studies/programmes, for example, the Guangdong-Hong Kong-Macau Joint Regional PM2.5 Study, which will help provide a scientific base in formulating policies to alleviate regional air pollution.

The above measures have borne fruit. From 2012 to 2016, our roadside and ambient air pollutants have dropped by up to 30 per cent and 21 per cent, respectively, while the ambient level of ozone has seen a slight decline of 3 per cent. However, amid the improvement trends, there are still episodes of high pollution when pollutants are transported from the delta region under unfavourable meteorological conditions. Hence, we have to continue our efforts to improve air quality.

We will continue to review the emission caps under the TM for power plants and we are preparing to tighten the emission standards for newly registered vehicles to Euro VI.

We will collaborate with the mainland authorities to set up a domestic emission control area in the Pearl River Delta waters in 2019, such that all vessels in the area will have to use low-sulphur fuel. Furthermore, we have embarked on a review of the air quality objectives (AQOs) to identify new practicable air quality improvement measures and assess the scope of tightening the AQOs made possible by their implementation. The review will be completed next year.

Mok Wai-chuen, assistant director (air policy), Environmental Protection Department
________________________________________
Source URL: http://www.scmp.com/comment/letters/article/2070763/drop-roadside-air-pollutants-hong-kong-thanks-government-measures

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.

China orders local meteorological bureaus to stop issuing smog alerts

China is suspending local meteorological bureaus from issuing smog alerts, media reported Wednesday, raising suspicions the government is attempting to suppress information about the country’s air pollution as public anger over the issue grows.

China’s Meteorological Administration notified local bureaus Tuesday to “immediately stop issuing smog alerts”, according to a photo of a notice posted on China’s Twitter-like social media platform Weibo.

Instead, the local departments can issue alerts for “fog” when visibility is less than 10 km, according to the notice.

The notice was issued because local “meterological bureaus and the environmental protection administration often disagree when they issue smog-related information,” a representative from the China Meteorological Administration told the Chinese website The Paper.

“A joint alerting mechanism will be formulated to consult how to and who should issue alerts for smog,” the representative said.

One single department will now be responsible for issuing smog alerts, The Paper reported.

The reports met with stinging criticism from online commentators who have long doubted the credibility of official data on air pollution.

“Before, they cheated us separately, and now, they are going to cheat us together,” one person said on Weibo.

“Even though they are working on a unified alert standard, they should not stop the existing alert system,” another replied.

The Chinese government has a colour-coded system of smog alerts, topping out at red when severe pollution is likely to last more than 72 hours.

The notice sets off a series of emergency measures, ranging from taking cars off the road to closing heavily polluting factories.

Local authorities have long hesitated to issue the notices over fears that they will harm economic performance, even when pollution levels are literally off the charts.

In late 2015, China issued its first ever red alert in response to public anger over the government’s reluctance to take action after a wave of suffocating smog hit the country’s northeast.

In the past, local and national authorities have issued contradictory, confusing alerts, one ordering factories and schools to be closed and one not.

Bad air is a source of enduring public anger in China, which has seen fast economic growth in recent decades but at the cost of widespread environmental problems.

In recent weeks, parents in particular have expressed outrage over the miasma that regularly affect hundreds of millions and has led to high levels of lung cancer, demanding that schools be equipped with air purifiers.

Earlier this month, many took to social media to express their anger about the thick smog that choked Beijing for over a week around the New Year but found their articles quickly deleted, a move that only increased their frustration.

“When people are gagged, the sky will be blue,” said one sarcasm-laced Weibo comment.

Hong Kong’s official air quality index failing to warn on deadly health hazard

Paul Stapleton warns that the Air Quality Health Index is creating a false sense of security by consistently failing to consider dangerous levels of PM2.5, the fine particulate matter associated with lung disease

Each morning after waking up, I look out of the window at the clarity of the air and then check two websites that give air pollution readings for Hong Kong.

Admittedly, my first action is very subjective. Air clarity is a crude way to measure pollution levels, especially during months that tend to be foggy. This is why I check the indexes on those two sites. Then, I decide whether to go out for a jog or stay indoors on the treadmill.

One of the websites is run by the Environmental Protection Department. It makes air-quality forecasts and generates a real-time Air Quality Health Index [2] scaled from 1 to 10+, or “low” to “serious”. The other site is the reputable World Air Quality Index (aqicn.org) [3], which measures only particulate matter less than 2.5 microns in diameter (PM2.5), one-thirtieth the width of a human hair.

These microscopic particles that just hang in the air are known to penetrate deep into our lungs when we breathe. They mostly come from vehicle exhausts, the burning of coal to make electricity and other industrial activities.

They are also known to be hazardous to health, especially of children; PM2.5 is associated with lung diseases, including cancer, as well as cardiovascular disease.

During the past week, the air pollution forecast on the local TV news each day, presumably taken from the government service, was for “low” to “medium” levels. However, at the World Air Quality Index, PM2.5 levels have been in excess of 100 for several days running. The US Environmental Protection Agency puts the 24-hour and annual standard for PM2.5 at 35 and 15 respectively. Thus, on days when Hong Kong’s Environmental Protection Department was informing the public that the level of air pollution was forecast to be low to medium, the amount of PM2.5 – arguably the mostly deadly pollutant – exceeded safe levels by a big margin.

In defence of the Air Quality Health Index, many other pollutants, such as ozone, sulphur dioxide and nitrogen oxides, are included in its composite measure, and their levels may have been “low”. However, even if their levels are low and only the PM2.5 is high, that does not mean it is safe to be outdoors for extended periods, especially for young children whose lungs are particularly prone to damage [6] by pollutants in the air.

Unfortunately, the discrepancy I noticed this past week is not an isolated incident. Regularly, the index forecasts the level of air pollution in Hong Kong to be “low to moderate” on the following day when the PM2.5 reading turns out to be at levels much higher than that acceptable by international standards. Sadly, the government’s daily forecast lends a false sense of security about air quality. In the end, it may be best to look out of the window and judge for oneself.

Paul Stapleton is an associate professor at the Education University of Hong Kong

________________________________________
Source URL: http://www.scmp.com/comment/insight-opinion/article/2061239/hong-kongs-official-air-quality-index-failing-warn-deadly

Easterly wind spares Hong Kong from Pearl River Delta smog

City’s air to remain relatively clean despite heavy pollution in nearby Foshan, Shenzhen and Guangzhou

The severe smog enveloping the Pearl River Delta will not affect Hong Kong for now thanks to the favourable wind direction, a representative from an environmental group said.

Despite high concentrations of harmful pollutants recently recorded in nearby Foshan, Shenzhen and Guangzhou, which saw the air quality index hit the hazardous 300 benchmark in some areas, Hong Kong has been able to enjoy a breath of fresh air because the easterly wind currently blowing through the city does not pass through the smoggy areas.

But a government official said regional efforts were needed to maintain healthy air quality in the city as New Territories West was vulnerable to pollutants produced in the adjacent mainland industrial zone.

“We don’t exclude the possibility that the smog might be blown into Hong Kong under favourable conditions,” Clean Air Network campaign officer Winnie Tse Wing-lam said during a radio programme on Friday. “But will Hong Kong turn into a smoggy city like Foshan? I don’t think so.”

Tse said the city will continue to be controlled by the easterly wind in the next couple of weeks, while the severe smog mainly affects cities located to the northwest of Hong Kong.

This means the air brought to the city will be relatively fresh.

Speaking on the same radio programme, Mok Wai-chuen, assistant director of air policy at the government’s environmental protection department, said cooperation with mainland cities in the Pearl River Delta was necessary to improve the air quality in Hong Kong.

He said the government had been working with the Guangdong provincial government to set emission reduction targets, and both sides will review the results in the first quarter of this year.

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, according to preliminary air quality data for 2016 released by the department.

However, much of the decline was due to wetter, windier weather in what are traditionally two of the most polluted months, January and October, according to Dr Cheng Luk-ki, head of scientific research and conservation at Green Power.

Source URL: http://www.scmp.com/news/hong-kong/health-environment/article/2059905/easterly-wind-spares-hong-kong-pearl-river-delta

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.