Air Pollution Linked to Higher Heart Attack Risk

BETHESDA, Maryland, March 23, 2009 (ENS) – Scientific evidence is mounting that connects an increase in particulate air pollution with an increase in heart attacks and deaths. Research from the relatively new field of environmental cardiology includes a 16-year-long Harvard University study of six U.S. cities that found fine particulate pollution, even at levels below the federal health standard, can shorten lifespans by two years. A majority of these earlier deaths were due to heart disease.

A study in Salt Lake City found that when a steel mill shut down for a period of months, there was a four to six percent drop in mortality in neighboring areas. The mortality rose to previous levels when the steel mill reopened.

A study of 250 metropolitan areas around the world found that a spike in air pollution is followed by a spike in heart attacks.

The people who seem to be most susceptible to environmental pollutants are those who are already vulnerable, including the elderly and people with coronary artery disease. There is some evidence that diabetics, women and people who are obese may be at greater risk.

Cardiovascular disease is the leading cause of death in the industrialized world. In the United States, it kills approximately one million people per year, accounting for over 40 percent of all deaths.

To examine this emerging research in greater detail, Aruni Bhatnagar of the University of Louisville and Robert Brook of the University of Michigan have organized a symposium called Environmental Factors in Heart Disease, to take place April 21 at an Experimental Biology conference in New Orleans. The 120-year-old American Physiological Society is one of the sponsors of the annual conference.

Dr. Bhatnagar, from the Division of Cardiology, Department of Medicine, University of Louisville, will speak on environmental aldehydes exposure and cardiovascular disease. His research shows that the risk of having a heart attack increases in parallel with time spent in traffic the previous day.

Joggers in San Francisco traffic inhale fine particles into their lungs. (Photo by Sharad Gupta)

In animal experiments, Dr. Bhatnagar has found that aldehydes – a toxic class of chemicals found in most forms of smoke, including cigarette smoke and car exhaust – increase blood cholesterol levels and activate enzymes that cause plaque in the blood vessels to rupture. When plaques rupture, it can cause a blood clot, which may block an artery and lead to a heart attack.

Aldehydes are present in high concentrations in smog and are generated during combustion of any kind of organic material coal, wood, paper, or cotton. “Direct exposure to high concentrations of unsaturated aldehydes is cardiotoxic,” writes Dr. Bhatnagar in a 2004 editorial in the “American Journal of Physiology.”

The evidence strongly supports the view that “exposure to environmental toxins significantly increases CVD [cardiovascular disease] risk, which contributes to the overall health burden of air pollution,” he writes.

Dr. Brook, an associate professor in the Department of Internal Medicine at the University of Michigan will speak on environmental pollution and hypertension. He has found that fine particles and ultra-fine particles entering the lungs can make their way into the blood vessels. Within 15 minutes of inhaling pollutants, there is a very rapid increase in blood pressure, he says.

Blood vessels react to the pollutants by producing an inflammatory response to attack the foreign particles. However, the inflammatory response itself can set off a complex physiological reaction that is harmful to the blood vessels, Dr. Brook says.

If you live in an area where pollution levels may be high, you can take steps to reduce the risk of air pollution, Dr. Brook advises. “During times when air quality is unhealthy, exercise indoors, because indoor air is filtered. If you exercise outdoors, particularly if you’re at risk for heart disease, do it when pollutants are at lower levels. Avoid peak traffic times,” he says.

Other speakers at the symposium include Araujo Jesus of the University of California, Los Angeles, who will describe the the effects of ultrafine air pollution of blood vessels, and Murray Mittleman of the Harvard School of Public Health will speak on the connection between air pollution and strokes.

Copyright Environment News Service (ENS) 2009. All rights reserved.


Every breath you take — air quality in Europe

Every breath you take — air quality in Europe
Courtesy of European Environment Agency (EEA)
Originally published Mar. 2009

The characters in this story are fictional. However the data are real. The story is set on 27 July 2008 when an air quality warning was issued in Brussels. Anna is 37 years old and lives in the centre of Brussels. She and her young son Johan are planning a trip outside the busy city. Anna suffers from asthma and her doctor has warned of the dangers of air pollution, especially on hot summer days.

Anna has heard about the London fogs of the 1950s that killed 2 000 people in one week. She has childhood memories of evening news bulletins showing dead fish and dying trees as ‘ acid rain’ first came to popular attention in the 1970s.

Motherhood and a recent asthma attack have quite rightly brought air pollution back to mind. The fact is that emissions of many air pollutants have fallen substantially across Europe since Anna’s childhood. The air she and Johan breathe is much improved compared to the past, and air policy is one of the great success stories of the EU’s environmental efforts. In particular, EU policy has dramatically cut emissions of sulphur, the main component of ‘acid rain’.

In contrast, nitrogen — also a major component of ‘acid rain’ — has not been dealt with to the same extent and so continues to cause major problems. A significant proportion of Europe’s urban population still live in cities where EU air quality limits, protecting human health, are regularly exceeded. Each year, many more people die prematurely from air pollution in Europe than die in traffic accidents.

The European goal of achieving levels of air quality that do not damage people’s health or the environment has still not been reached. EEA analysis suggests that 15 of the 27 EU Member States will miss one or more of their legally binding 2010 targets to reduce harmful air pollutants.

Particulate matter and ozone
Two pollutants, fine particulate matter and ground-level ozone, are now generally recognised as the most significant in terms of health impacts. Long-term and peak exposure can lead to a variety of health effects, ranging from minor irritation of the respiratory system to premature death.

Particulate matter, a term used to describe a variety of tiny particles from sources such as vehicle exhausts and domestic stoves, affect the lungs. Exposure can harm people of all ages, but people with existing heart and respiratory problems are particularly at risk.

According to the latest EEA data, since 1997 up to 50 % of Europe’s urban population may have been exposed to concentrations of particulate matter above the EU limit set to protect human health. As much as 61 % of the urban population may have been exposed to levels of ozone that exceed the EU target. It has been estimated that PM2.5 (fine particulate matter) in air has reduced statistical life expectancy in the EU by more than eight months.

The EEA has noted that while emissions of these two key air pollutants have dropped since 1997, measured concentrations in the air we breathe have remained largely the same. As yet, we don’t know why there has not been a drop in ambient concentrations but it could be a combination of several factors: increased temperatures caused by climate change could be affecting air quality; perhaps we are on the receiving end of pollution from other continents or natural emissions of ozone forming substances released from trees, for example.

A day in the country
Anna is planning a day in the country with Johan. Before leaving her apartment she logs onto IRCEL, a government web service providing a host of regular information on air quality around Belgium. Using maps, Anna can scan readings and forecasts for particulate matter, ozone, nitrogen dioxide, sulphur dioxide among many others. The data are relayed to the web from monitoring stations around the country.

Improvements in monitoring and availability of information on air pollution are another of the success stories of recent years. For instance, local data on ozone levels are now passed onto the EEA ‘Ozone web’ (1) service that provides an overview of the situation across Europe.

Anna scrolls across a map of Belgium, zooming in on a monitoring station in the centre of Brussels, less than two kilometres from her home.

The reading, taken minutes earlier, shows high levels of ozone in Brussels. Indeed the website forecasts that levels will exceed EU target values later that day and again the following day ( Figure 1).

Anna leaves her apartment building and makes for the nearest Metro station, a 10 minute walk away. Out on the street, the full impact of the city’s traffic problems are easy to see — and smell.

Exhaust emissions from cars in the centre of Brussels, and all major cities, irritate the respiratory tract and eyes and lungs. Anna and Johan turn into their local train station and head for the countryside.

Soon, Anna and Johan are entering a national park just outside Brussels. A sign tells them that they are visiting a Natura 2000 site — one part of a European-wide ecological network, set up to secure natural habitats and to maintain the range of plant and animal life.

Figure 1: The location and levels of ozone at air quality monitoring stations in Brussels on Sunday 27 July 2008

But what’s that smell? A tractor is spraying liquid manure onto a field not far away. This is irritating, Anna thinks, but it’s also part of real country life which is shown in a rather more romantic way in Johan’s picture books.

The pungent smell is caused by as many as 40 different chemical substances emitted from the manure. Ammonia (NH3), a volatile nitrogen compound, is one of them. In very high concentrations NH3 is caustic and can damage the respiratory tract. However, the levels here are not dangerous for human health. Anna can breathe a sigh of relief, albeit a stinky one.
Nitrogen is an essential nutrient in nature. Reactive nitrogen forms are actually used by our bodies to produce proteins. However, excess nitrogen can lead to severe environmental and health problems.

‘Acid rain’ forms when high levels of sulphur and nitrogen oxides are present in the air. One of the great success stories of air pollution policy over the last decades has been the massive reduction in emissions of sulphur dioxide. The 32 EEA member countries reduced sulphur emissions by 70 % between 1990 and 2006. Nitrogen, on the other hand, has not been dealt with as successfully.

With sulphur emissions declining, nitrogen is now the principal acidifying component in our air. Agriculture and transport are the main sources of nitrogen pollution. Agriculture is responsible for more than 90 % of ammonia (NH3) emissions alone.

Suddenly Johan, who has been walking unsteadily loses his balance and falls into a clump of stinging nettles. Having picked him up and brushed him off, Anna notices nettles everywhere. She has vivid memories of them as a child in a neighbour’s garden. Then the nettles grew around a compost heap that was also used as a dump for poultry dung. That was no coincidence — the stinging plant is an indicator of high nitrogen concentrations in soils.

‘Eutrophication’ is the most likely cause of this explosion of stinging nettles surrounding Johan. It occurs when too many chemical nutrients (such as N) are available to an ecosystem either on land or in water. In water, excessive plant growth and subsequent decay occur, which in turn leads to further effects including oxygen depletion. Fish and other animals and plants ultimately suffocate as the oxygen supply is used up.

The abundance of the nettles here suggests that despite being a protected habitat, the Natura 2000 site is not immune from airborne nitrogen deposits. The fence protecting the area offers no defence — in fact building a greenhouse around the area would be the only way to protect it totally from airborne substances.

Looking ahead
Because air pollution pays no regard to national boundaries the problem needs to be tackled internationally. The United Nations Convention on Long-range Transboundary Air Pollution (LRTAP Convention) agreed in 1979, has been signed by 51 countries and forms the basis of the international fight to tackle air pollution.

In parallel, the EU has developed polices limiting the total emissions of each Member State, setting legally binding limits. The ‘ National Emissions Ceiling Directive’ (NECD) is a key EU policy. It sets ‘ceilings’ or limits for four pollutants: sulphur dioxide (SO2), nitrogen oxides (NOx), non-methane volatile organic compounds (NMVOCs), and ammonia (NH3). Member States should meet these ceilings by 2010.

The EEA considers that further emission cuts are still needed in order to properly protect environment and health. An EEA analysis of the most recent NECD data (2) indicates that 15 Member States expect to miss at least one of their four ceilings; with 13 anticipating missing ceilings for the 2 nitrogen-containing pollutants NOX and NH3 (3).

In 2009 the European Commission plans to publish a proposal to revise the current NECD, including stricter ceilings for the year 2020. National limits are likely to be proposed for fine particulate matter (PM2.5) for the first time.

The NECD is mirrored by air quality directives setting limit and target values for major air pollutants. A new one called the Cleaner Air For Europe (CAFE) Directive was adopted in April 2008. For the first time it sets legally binding limit values for PM2.5 concentrations (fine particulate matter), to be attained in 2015. The European Commission is also taking countries to task for having missed earlier limits and, where sufficient measures have not been outlined to improve performance, has begun infringement proceedings.

Later that evening Anna, while watching the evening news, sees that an air quality warning has been issued by the government in response to high ozone levels beyond the EU threshold. The warning advises people with breathing problems to take precautions such as avoiding strenuous exercise while the ozone levels remain high.

Climate change mitigation efforts will improve air quality

In January 2008, the European Commission proposed a Climate and Energy package to:

  • reduce greenhouse gas emissions by 20 % by 2020;
  • increase the share of renewable energy by 20 % by 2020;
  • improve energy efficiency by 20 % by 2020.

The efforts required to meet these targets will also cut air pollution in Europe. For example, improvements in energy efficiency and increased use of renewable energy will both lead to reduced amounts of fossil fuel combustion — a key source of air pollution. These positive side effects are referred to as the ‘co-benefits’ of climate change policy.

It has been estimated that the above package will cut the cost of meeting EU air pollution targets by EUR 8.5 billion per year. The savings to the European health services could be as much as six times that figure.

Lung Association Supporting Drive Thru Moratorium

Lung Association Supporting Drive Thru Moratorium
January 9, 2009

The province’s lung association has thrown its support behind the city’s moratorium on new drive thru’s. Spokesperson Greg Noel says they have been encouraging the public to limit vehicle use for some time, because of environmental and health concerns. Noel says while they may be pursuing change for different reasons, the association is pleased with the debate taking place. Noel notes it is not just drive thrus that cause the Lung Association concern. He says idling vehicles in general can have harmful health effects.