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The Threat In Our Indoor Air

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PM2.5 fine particles linked to health risks and a wide range of diseases in homes and workspaces


Few people will have missed the television images broadcast globally of the men, women and children living in China's huge metropolitan areas suffering horrific levels of air pollution. But China is not alone. Almost every major urban area on the planet suffers significant outdoor and indoor airborne pollution that threatens our health and well-being.

Outdoor and indoor air pollution are two sides of the same coin. Yet a great many people remain oblivious of the link between the contaminated air they are breathing in their homes and workplaces and a huge range of health and well-being problems.

Fine particles commonly known as PM2.5, stemming from sooty exhaust fumes, industrial processes and a spectrum of household chemicals, have been linked in studies to cancer, asthma, infertility and even birth defects.

A 2012 report from the World Health Organization (WHO) on the impact of chemicals on human health notes that the "prevalence of pediatric asthma has more than doubled over the past 20 years and is now the leading cause of child hospitalization and school absenteeism". And new research carried out in 10 European cities has estimated that 14 percent of chronic childhood asthma is due to exposure to traffic pollution near busy roads.

Clearly, the health consequence of airborne pollution are worsening as levels of fine particulate matter soar in our homes and workplaces.

This White Paper surveys the research into the threats to health being sparked by particulate matter in our indoor air. And it warns of the very real necessity for more urgent effort by governments and health authorities to address the issue of indoor air quality to avoid potentially catastrophic health consequences for future generations.

This is particulate matter (PM)

* Particles found in dust, soot and liquid droplets come in a variety of sizes, some visible to the human eye and others only detectable by using an electron microscope.

* PM10 and PM2.5 are each measured and expressed as the amount (in micrograms) of particles contained in a cubic meter of air, expressed as micrograms per cubic meter.

* PM10 refers to particles that are 10 microns in diameter or less.

* PM2.5 (or fine particles) refers to particles that are 2.5 microns in diameter or less.

* A human hair typically measures 70 microns in diameter, while a grain of sand is about 90 microns.

* Breathing in PM has been linked in many scientific studies to a significant number of health problems, including aggravated asthma, difficult or painful breathing, chronic bronchitis and decreased lung function.

* Breathing PM has also been linked to premature death.

The Indoor Air Problem

Are we being poisoned by living everyday life in our homes and workplaces? In Europe, America, China, Japan and elsewhere we spend as much as 90 percent of our time indoors, but how many of us think much about the air we are breathing inside our homes, offices and even sports halls?

Arguably indoor air pollution is one of the most overlooked threats to human wellbeing and health despite being considered the fourth greatest pollution threat to us all by the U.S. Environmental Protection Agency (EPA). Underlining this, a report from the UN's World Health Organisation (WHO) says many chemicals found in household and industrial products that have not been adequately tested may also have disrupting effects on the human hormone system and lead to significant health issues.

From the outside in

Most air pollution is caused by humans and derives from the combustion of fossil or other fuels. Major sources of outdoor airborne pollution are exhaust fumes from cars, trucks and buses, emissions from factories and power plants and smoke emanating from residential heating and cooking.

Urban outdoor pollution is measured according to hourly, daily or even annual mean concentrations of particulate matter (PM10 or PM2.5) in urban backgrounds such as traffic areas, residential areas and commercial areas.

Particles come in a wide range of sizes, but are usually measured as either "fine particles" that are less than 2.5 micrometers in diameter (PM2.5) or "coarse particles" ranging between 2.5 and 10 micrometers in diameter (PM10).

PM2.5 particles that are less than 2.5 micrometers in diameter are so small that they can easily be drawn into the lungs when breathing and potentially cause serious health problems, including respiratory and heart diseases. Fine particles result from all types of combustion, including motor vehicles, power plants, some industrial processes, and burning wood, while coarse particles, which can irritate your eyes, nose and throat, stem in part from dust stirred up by road traffic.

All particles pose a potential health or well-being risk, and the threats have been well documented. In the U.S., the State of California's Environmental Protection Agency's Air Resources Board (ARB) has written, "both short- and long-term exposures to particulate matter (PM) have been shown to lead to harmful health effects. A large body of evidence has shown significant associations between measured levels of PM outdoors and increases in the numbers of human deaths.

In addition, scientists have observed higher rates of hospitalizations, emergency room visits and doctor's visits for respiratory illnesses or heart disease during times of high PM concentrations. During these periods of high PM levels, scientists also observed the worsening of both asthma symptoms and acute and chronic bronchitis. Scientists have found a relationship between high PM levels and reductions in various aspects of the healthy functioning of people's lungs."

Even more alarmingly, from a long-term perspective, a data analysis from ARB's Children's Health Study shows health effects in children, as well. The study revealed that in communities highly polluted with PM, children's lungs developed more slowly and did not move air as efficiently as children's lungs in clean air communities.

Children and infants are more exposed to harm from inhaling pollutants such as PM because they inhale more air per kilo of body weight than adults do - they breathe faster, exercise more and have smaller body sizes. Also, children's immature immune systems may cause them to be more at risk from PM than healthy adults.

California has set ambient air quality standards for PM that are lower than the corresponding standards set by the U.S. EPA. California's average annual PM2.5 standard for the maximum amount of particles that can be present in outdoor air without threatening the public's health is 12 micrograms per cubic meter (µg/m3), compared to 15.0 µg/m3 set by the EPA.

Informed decisions

The World Health Organization has established air quality guidelines that recommend humans should not be exposed to PM2.5 over the long-term exceeding an annual mean average of 10 micrograms per cubic meter. The organization recognizes not every country is in a position to realistically achieve that goal so WHO offers different air quality gradings to allow a country to gradually move towards interim targets leading to the overall limit.

There are several other air quality standards used around the world such as the U.S. National Ambient Air Quality Standards and the EU's Air Quality Directive, which are based on maximum atmospheric concentrations for specific pollutants.

One measurement that has been used to spotlight high levels of PM2.5 is the U.S. Air Quality Index (AQI), an index for reporting how clean or polluted air is. The AQI is a yardstick used across North America that runs from 0 and upwards measuring, on an hourly basis, the amount of five major air pollutants such as ground-level ozone, particle pollution and carbon monoxide in the air. So, for example, an AQI value of 50 represents good air quality, while any figure above 150 is considered unhealthy and anything above 300 as "hazardous".

In Europe, sixty scientists in 12 European countries spent three years measuring the health impact of air pollution in 25 cities. Their Aphekom research program shows that a decrease to 10 µg/m3 of long-term exposure to PM2.5 fine particles (WHO's annual mean air-quality guideline) could add up to 22 months of life expectancy for persons 30 years of age and older, depending on the city and its average level of PM2.5.

In the cities studied, Aphekom's health impact assessment (HIA) showed that living near roads carrying heavy traffic could be responsible for some 15-30 percent of all new cases of asthma in children; and of COPD (chronic obstructive pulmonary disease) and CHD (coronary heart disease) in adults 65 years of age and older. The study noted that in the cities studied, which included Barcelona, Brussels, Vienna and Stockholm, some 50 percent of the population lives within 150 meters of roads travelled by 10,000 or more vehicles per day, exposing them to "substantial levels of toxic pollutants".

The Aphekom study concludes that exceeding the WHO air-quality guideline on PM2.5 leads to a burden on mortality of nearly 19,000 deaths per annum, more than 15,000 of which are caused by cardiovascular diseases. Aphekom also determined that the monetary health benefits from complying with the WHO guideline would total some €31.5 billion annually, including savings on health expenditures, absenteeism and intangible costs such as well being, life expectancy and quality of life.

Reduced life expectancy

The 8 million people living in the British capital London, for example, suffer some of the worst air pollution of any UK or European city, and air quality is a very significant issue for Londoners' health. The Department for Environment, Food and Rural Affairs (Defra) estimates that current PM2.5 (Particulate Matter) emission levels reduce average life expectancy of people in the UK by six months and cost the economy £15 billion each year; equivalent to the cost of obesity in urban areas. The situation is particularly bad in London where 4,300 deaths each year are thought to be attributable to air pollution (the individuals dying, on average, 11 years prematurely).

Year of the air

The European Union has declared 2013 the "Year of the Air". However, the European Environmental Bureau itself has stated current EU standards for ambient air quality are weaker than those recommended by the World Health Organization (WHO) which are intended to minimize the health effects of air pollutants.

For fine particles (PM2.5), which is one of the pollutants with the highest impact on people's health, the maximum concentration allowed is 25 µg/m3, currently 2,5 times higher than what the WHO recommends for this pollutant, and will only enter into force in 2015. In comparison, the US Environmental Protection Agency has proposed an annual limit of 12 µg/m3 for PM2.5 which is much more ambitious than the EU standards.

China acts positively

Weak as they are, the EU standards, some of which were agreed more than 10 years ago, are still breached by most EU Member States. Even China, where the PM2.5 debate has been brought to the forefront, a national clean air law with bite is now on the horizon with a number of pollution-reduction measures already underway that includes real-time air quality monitoring data on PM2.5 intensity in China's 74 major cities and a plan to cut emissions of gas and pollutants in its most economically dynamic areas.

According to the Chinese Ministry of Environmental Protection's plan for reducing overall air pollution, China will cut the PM2.5 intensity by at least 5 percent by 2015 in 13 major areas covering 117 cities.

"Escaping indoors" is not a good idea

In 2012 researchers at the leading University of Umeå, in northern Sweden, released a study of pregnant mothers that indicated high levels of traffic exhaust fumes and ozone can lead to a bigger risk of premature birth than the mother smoking. The authors suggested it would be safer for them to stay inside their homes.

Sadly, the advice from the Umea University research team can be viewed as potentially misleading. There is well documented evidence indicating homes and work spaces suffer higher levels of airborne pollutants than most people are aware about.

In many areas of the industrialized world, humans spend around 90 percent of their time indoors, so the question we should all be asking is which is worse: breathing in air at a busy traffic intersection or inside our own homes or workspaces? There is no easy answer. A recent overview of global health risks published in The Lancet has revealed the deadly nature of air pollution with 3.2 million people dying prematurely from outdoor air pollution in 2010 and 3.5 million dying prematurely as a result of indoor air pollution.

The American EPA has said indoor air can be up to 100 times more polluted than outdoor air. Indoor air may be contaminated as a result of external emissions, building more airtight buildings to conserve energy, inadequate ventilation and the use of home cleaning products and furnishings that emit harmful gases such as formaldehyde or ammonia.

Although health authorities around the world acknowledge that poor air quality can be a contributing factor to health problems, very few countries have taken steps to vigorously regulate indoor air quality. However, both Taiwan and South Korea have introduced tough new regulations to improve indoor air and acknowledged that poor domestic and work air quality can spark headaches, fatigue and skin problems.

Every day we come into contact with things in the environment that affect our health. Air pollution is hard to avoid because we are exposed to it when commuting to and from work or school, when we exercise and in our homes and offices.

The air we breathe is filled with particles and chemicals. One study of household air in Arizona found over 400 chemicals ranging from pesticides to phthalates, while a European Union study says indoor air may contain more than 900 different organic compounds in addition to particles, microbes, and allergens.

PM2.5 is not just an outdoor problem

Indoors, PM2.5 pollution comes from sources such as smoking, cooking, and cleaning, and PM2.5 that has infiltrated from the outside. Although there has been considerably less research into indoors PM2.5 and cardio-respiratory morbidity, Health Canada reported researchers had found a link in asthmatic children between indoor PM2.5 and declines in lung function.

A study of ten work places in busy street canyon in Dublin, the Irish capital, showed results indicating that indoor concentrations of PM2.5 can be significantly greater than outdoor concentrations. Dutch researchers evaluating long term exposure to traffic have found that people who lived near a main road were almost twice as likely to die from heart or lung disease compared with those who lived in less trafficked areas.

Research conducted in 10 European cities has estimated that 14 percent of chronic childhood asthma is due to exposure to traffic pollution near busy roads. Published in the European Respiratory Journal in late March 2013, the results are comparable to the burden associated with passive smoking: the World Health Organization (WHO) estimates that between 4% and 18% of asthma cases in children are linked to passive smoking.

Most of us, and especially the very young, those in ill health and the elderly, spend up to 90 percent of our time inside our homes and at work. As a result, the indoor domestic or work environment is a key contributor to an individual's exposure to many particle pollutants.

The American Lung Association says that because of the population exposed, the complexity of the components and the wide ranging health effects, PM2.5 is likely the most lethal air pollutant, increasing the risk of early death from heart disease, lung disease and cancer - the three top causes of mortality in the U.S.

Solving the indoor air threat

Individual people and businesses already have the means to remove pollutants from their indoor air, speedily and efficiently by increasing ventilation and/or using indoor air purifiers.

The problem most people face is that outdoor air is contaminated with particle pollution from traffic, industry and nature (especially during allergy season) that infiltrates into buildings. So ventilation is not necessarily the best option in a metropolitan area. Nor is it practically feasible to remove all the indoor sources of the household contamination, such as the chemicals found in fire-retardant or building materials.

Blueair air purifiers are designed to remove 99.97 percent of all the bad stuff in the air faster than any competing products to help avoid respiratory problems like coughing, chest tightness, and sore throat. Blueair's air cleaning technology also helps banish symptoms like watery or itchy eyes, shortness of breath, headache, bronchitis and full-blown asthma or other allergy attacks.

Blueair air purifiers remove all the burdens of allergens associated with indoor air quality such as pets, dust mites, mold and bacteria as well as cold and flu viruses. A Blueair air purifier is proven by independent research to rid indoor air of PM10 and PM2.5 particles, including dust, traffic and industrial particles as well as the volatile organic compounds (VOCs) found in cleaning products such as chlorine, ammonia, paints, floor polishes, furnishings - even air fresheners.

To back up its claims, Blueair adheres to the worldwide Clean Air Delivery Rate (CADR) measurement standard established by the U.S. independent industry organization, the Association of Home Appliance Manufacturers (AHAM). Used by the U.S. Environmental Protection Agency (EPA) in its Air Cleaner Energy Star Program and endorsed by the U.S. Food and Drug Administration (FDA), CADR helps tell a consumer how efficient air purifiers are at removing contaminants from indoor air.

Independent evidence indicates that using indoor air purifiers with advanced air cleaning technologies such as those delivered by Blueair can help reduce that burden of disease and suffering.


There is little doubt particulate matter poses a threat to human health and well-being. Children are particularly at risk. Lungs do not fully develop until our teens and exposure to particle pollution can cause lifelong respiratory problems. Fine particles also travel long distances to impact communities far from where they were created to contaminate the countryside, farm crops, rivers and coastal waters.

Mostly invisible to the human eye, particulate pollution according to scientific evidence causes eye, nose and throat irritation, respiratory infections and bronchitis, and cancer.

Blueair believes governments and health authorities in Europe and worldwide need to take a new look at air quality standards. Indoor air quality especially has taken a back seat to outdoor air pollution despite the fact that building regulations designed to save energy are creating home and workplace environments that encourage the accumulation of hazardous pollutants such as particulate matter.

High levels of particulate matter both outdoors and indoors pose a major threat to human life, health and well-being in all urban areas of the world. Children are most at risk because our lungs do not fully develop until we are in our teens and exposure to particle pollution can create lifelong respiratory problems.

Knowing how many lives could be saved and health problems avoided, it is unacceptable to ignore the facts. At Blueair, we ask heads of government and health authorities globally to speed their efforts to adopt stronger, more protective air quality standards to protect the health of future generations.

Blueair believes it is vital more national governments acknowledge the extent of the problem, work to raise public awareness and introduce legislation that will lead to cleaner indoor air at home and work.

Health Disclaimer. Copyright ©2015. Published with permission.