To Reduce Exposure to Pollution on Your Commute, Crank The Air Conditioning

New research suggests the best way to minimize your pollution exposure on the commute to and from work is to crank the air conditioning in your vehicle.

Most Americans spend almost an hour traveling to and from work each day. And it is during the commute that people experience the majority of their daily exposure to contaminants.s

To determine how drivers and passengers might mitigate their exposure risks, scientists at Washington University in St. Louis tested what effects the car ventilation system has on passing pollutants.

Scientists tested different combinations and fan and air conditioning settings and monitored contaminant concentrations using portable sensors. A dashboard camera allowed scientists to determine how outside variables — a restaurant exhaust system or a passing diesel truck — impacted exposure.

“As aerosol scientists, we had access to state-of-the-art air monitoring equipment,” Nathan Reed, a doctoral candidate at WUSTL, said in a news release. “Once we began measuring inside and outside of the car, and started getting numbers back, we were able to confirm our hypothesis that by controlling our car’s ventilation we could mitigate some pollutant risk.”

Researchers found that using air conditioning reduced the amounts of the pollutants inside the vehicle by 20 to 34 percent. While the fan and AC both pull air from the outside, the air conditioning system sees air passed across a cold evaporator.

“This cold surface attracts the pollutant particles, and they deposit there, as opposed to diffusing it into the air you’re breathing,” Reed said.

Scientists found the AC was best at minimizing pollution exposure when following a heavy polluter like a bus or big rig.

Of course, using the AC also diminishes a car’s fuel economy, contributing to auto emissions. Scientists recommend deploying the AC only when presented with a high pollution exposure scenario. Once the truck or bus is gone, the driver should role down the windows to allow any buildup of pollutants to dissipate.

Scientists detailed their experiments in a paper published this week in the journal Atmospheric Environment.

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Los Angeles Tests Cooling Pavement Paint to Combat Climate Change

Normal black asphalt absorbs 80 to 95 percent of sunlight, but painting road surfaces grey reflects the sun’s rays, helping to cool urban temperatures.

The problem of global air pollution

The World Health Organisation (WHO) expect poor air quality worldwide to be the leading cause of premature deaths by 2050. They probably look back at the Paris Climate Accord of December 2015 with mixed emotions. First off, replicating the wide consensus about climate change for the effects of air pollution on population health would be a worthy ambition. Then again, they must now look at how recent populist resistance, particularly by the Trump presidency in the US, has set back the cause of legislating against environmental degradation. They might wish for no more horse-trading over whys and wherefores, just consensus on what needs to be done, then getting on with it.

But in seeking agreement on how to improve air quality, WHO do themselves few favours. Their standard parameter of suffering from poor health is the Disability Adjusted Life Year or ‘DALY’, measuring numbers of years lost to ill health, disability or death, against a notional average healthy life expectancy. Not surprisingly, this peasoup of statistical complexity is argued over by medics, demographers and sociologists threatening the capacity to agree anything about how to tackle the poisoning of our lungs.

We all accept the root causes of poor air; most are man made. They include the vastly increased reliance on the internal combustion engine over the last half-century, particularly in rapidly growing economies. But emissions from industrial processes, and urbanisation with its encroachment on previous areas of virgin, or partly domesticated natural vegetation, are just as guilty. Nature adds its own contribution via volcanic emissions and the minority of forest fires not started by man, but largely we are responsible for the deteriorating quality of the air we breathe. We know the causes, so we should be able to identify the solutions to slow and eventually stop, worldwide decline in air quality.

In most developed economies, there are some promising starts. Coal-fired power generation is now a fraction of what it was 30 years ago. Sustainably sourced generation continues to rise as its lifetime and operating costs continue to fall. We still have a way to go on vehicle emissions, but again we’ve made a start. Old vehicle scrapping schemes, congestion charging and a new wave of road pricing all act to encourage more use of public transport and ultra low emission zones will soon make it too expensive to move freight with anything other than vehicles with the cleanest emissions, if not electric motivation. These measures cannot come soon enough for cities across the developed world where climate warming over the last two decades is exacerbating toxic air quality.

But how can we deliver such improvements to developing economies where the worst air quality deterioration is found? Not, I suggest, by arguing endlessly over the health statistics. We need positive and practical measures on the ground.


Schemes scrapping ageing and inefficient cars for those with more efficient engines would have a major impact in fast developing economies, where reliance on private vehicles is the only solution for the livelihoods of marginally coping communities. A subsidy scheme by motor industry offenders over recent NOx emission cheating, replacing old with new models might be too much to hope for, but consumer loyalty would be engendered worldwide by an international gesture of this sort. VW and others, are you listening?

Greater investment in public transport infrastructure is at last becoming a viable sector for the finance industry, as it seeks out longer term returns for its insurance and pensions customers. Only the most secure covenants are attracting the right quality of project funding capital, but where this ventures into developing economies, it needs underwriting via World Bank and other overseas aid agencies.

Hydrocarbons-fired power generation in, for example China and South East Asia, as already in the west, needs steady replacement by sustainable sources, as already occurring in the west. Those losing jobs in mining and facing the burden of unemployment, could be re-trained to manufacturing jobs in fast-growing renewables. There is ample experience to build on here from across western Europe. Rapidly reducing costs of sustainable energy generation needs importing to economies where they will soon be needed most to compete with continued low labour costs in mining and extraction.

Air pollution Kuala Lumpur, Malaysia

Finally, urban planning has to become a stronger feature of land use management, thus optimising development of previously green space on the edges of towns, and only allowing urbanisation to expand beyond current city limits where take-up of underused space inside the urban envelope is impossible. Effective land use management has a huge if indirect contribution to make to reduce air pollution.

The long-term effects of degraded air are measurable in the treatment of respiratory disorders and associated loss of earnings or death with its associated dependencies from what would otherwise be healthy populations. Society has to develop cross accounting, so that the costs of installing physical infrastructure now, pay for reduced health care later. Only by making such mould-breaking accounting solutions work effectively, will we achieve the benefits of a truly joined-up world economy.

Hugh’s new book is Journeys with Open Eyes, Seeking Empathy with Strangers, £12.98 (i2i Publishing).

Hugh is a graduate of Oxford (St. Johns, 1969). For over for decades he has worked for an array of public and private sector in international urban planning and development.

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Vapor Intrusion: What FMs Need to Know

Vapor intrusion is the migration of potentially harmful chemical vapors into a dwelling or occupied building from a subsurface source. This migration can lead to an accumulation of chemical-containing vapor. Evidence of toxic vapor intrusion is often found at various sites where manufactured chemicals such as petroleum hydrocarbons and chlorinated solvents are present in the groundwater, soil, or soil vapor. As vapor intrusion occurs, a building’s habitable indoor air quality is negatively affected and can lead to possible health risk. The types of chemicals which are major culprits in the concern of vapor intrusion are volatile organic compounds (e.g., trichloroethylene), petroleum hydrocarbons (e.g., gasoline), and semi-volatile organic compounds (e.g., naphthalene).

According to the United States Environmental Protection Agency, recognition of soil vapor intrusion to buildings and other enclosed spaces occurred in the 1980s with concerns over radon intrusion. There was an increasing awareness that  man-made chemicals in soil, groundwater, and sewers could pose a threat to indoor air quality.

In addition to health risks that vapor intrusion poses, there are financial implications to this environmental condition as well. There are lawsuits on record of having been filed against various businesses for their dangerous air quality due to vapor intrusion. Class action lawsuits have been settled at upwards of $8 million in certain cases.

The source of a vapor intrusion risk is not always on the property being developed. Soil, groundwater, and soil vapor contamination can migrate a great distance, depending on soil characteristics, from the initial location of release onto adjacent properties as well as properties considerably down gradient. This movement of chemicals may result in a vapor intrusion risk below a proposed or existing structure without there having been any history of storage or use of these chemicals on the property at issue.


From a new construction point of view, land assessments are continuing to become more thorough. Doing their due diligence on the history of the land and being sure to test for the presence of the volatile chemicals is becoming a standard operating procedure before finalizing plans on a new development. If it is determined that vapor intrusion is indeed a real potential risk for the site, architects are now specifying that something be done to mitigate this risk. This mitigation comes in the form of chemical vapor barriers, not to be confused with standard moisture barriers (too often referred to as vapor barriers). Chemical vapor barriers are being laid down underneath the foundation to block dangerous vapors from migrating into the habitable zone of the future building. Contractors are receiving the specifications of new projects that include a chemical vapor barriers on a more regular basis.

But what if there is a vapor intrusion risk in a facility that is already standing? Is there anything that can be done at this point? Fortunately, there are solutions for this type of situation.

There are chemical vapor-barrier products that are specifically designed for existing structures. Sealant materials are applied to the top of the slab as opposed to the bottom, as they would if the chemical vapor barrier were applied before the foundation is laid. Facility managers are finding this retroactive installation of a chemical vapor barrier attractive because it not only acts as a useful vapor mitigation system but it also doubles as a finished floor surface. Because it coats the floor, the system is always “on” and always working. Alternatively or in addition to the sealant product described above, is the installation of a depressurization system below the slab in order to provide a piped pathway leading chemical vapors away from the interior of a structure. These are known as sub-slab depressurization systems. Essentially, these systems act as a fan blowing out any contaminants. However, these systems do have to be continually powered, require a level of maintenance to ensure continued effectiveness, and require trenching below the slab and reconstruction of the slab to install.

It is important for a facility manager to understand if there are harmful chemical vapors migrating into an existing structure. After testing, if it is determined that there is a risk, the next step would be to consult a chemical vapor installation professional to do a site assessment and help determine the best course of action.

Wesley Robb is director of technical strategies and applications of Vapor Mitigation Strategies and has more than 23 years of environmental field and laboratory experience including several years of soil vapor sampling and analyses. He can be reached at

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Indoor Air Pollution: The Hidden Health Hazard

Breathing is a double-edged sword. It’s essential for survival, but in some places, the air quality poses significant health risks. Exposure to air pollution is linked to lung cancer, asthma attacks, cardiovascular damage, reproductive harm, and more.

Experts claim our air quality has improved remarkably over the last few decades thanks to the Clean Air Act, but many still see plenty of room for improvement.According to the American Lung Association’s latest “State of the Air” report, 40 percent of Americans live in states that have unhealthful levels of air pollution.

Scientists, policy analysts, and public health advocates from across the country met to discuss the state of the nation’s air quality at a summit hosted by The Atlantic magazine in Chicago in April.

Much of the event focused on rules that govern outdoor air quality, and the health conditions that result from exposure to things like vehicle emissions and coal-fired power plants. But according to panelist Joseph Allen, professor of exposure assessment science at Harvard University, the majority of pollution exposure occurs inside—in our schools, homes, and workplaces.

“Outdoor air pollution penetrates indoors. And because of the time we spend inside, your daily dose can actually be greater indoors,” he said.

Chemical Exposure

Pollutants that originate outside get a lot of attention from regulators, and for good reason. In a study published in 2013, researchers from the Massachusetts Institute of Technology tracked emissions throughout the United States and found that air pollution from vehicles, industry, and other sources causes about 200,000 early deaths each year. Vehicle emissions alone were responsible for 53,000 premature deaths—about 15,000 more than were caused by car accidents.

However, research demonstrates that chemicals that originate indoors may be just as harmful. According to the U.S. Environmental Protection Agency (EPA), in some cases, concentrations of indoor pollutants have been shown to be twice as high as those outside. This is particularly concerning because we spend the vast majority of our time—around 90 percent—indoors.

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Some indoor pollutants, such as radon gas, naturally emanate from the earth and seep into buildings through cracks in the foundation. Mold and legacy toxins such as lead and asbestos are hazards that must also be dealt with in order to protect our precious breathing space.

However, the majority of indoor toxins come from sources we voluntarily bring into our environment.

There are about 82,000 chemicals in commercial use, and no available health data for 85 percent of them. In the last few years, researchers have learned a lot about the risks associated with exposure to many indoor air pollutants, but the vast majority remains a mystery.

Even the products we use to freshen up our environment, such as dryer sheets, synthetic fragrances, and cleaning products, may cause more harm than good. According to the Environmental Working Group, the popular air freshener Febreze contains chemicals that have been found to affect the respiratory and nervous systems.

Protecting Your Space

Do as your grandparents did and open the windows to increase the ventilation.(gpointstudio/iStock)

Do as your grandparents did and open the windows to increase the ventilation.(gpointstudio/iStock)

Harvard’s For Health website provides science-backed guidelines on how to create a healthy indoor environment. When choosing products that will share your breathing space, there are three chemical families of particular concern:

Flame Retardants: Found in items such as furniture and building insulation, as well as products designed for children such as toys and car seats. Many of these chemicals are endocrine disruptors, chemicals that have been shown to interfere with the reproductive system, thyroid function, and other aspects of the endocrine system.

Stain-Resistant Chemicals: Found in furnishings, carpets, clothing, nonstick cookware and paints, and other products designed to repel oil and water.

Plasticizers: Particularly phthalates—a class of chemicals used to make products soft and flexible. Phthalates are found in vinyl tile, artificial leather, and even some brands of personal care products such as nail polish, hairspray, and skin lotions.

Other common indoor pollutants found to pose risks to human health include nitrogen oxides, carbon monoxide, particulate matter, and volatile organic compounds (VOCs) such as formaldehyde, limonene, and benzene. These pollutants may come from printer emissions, cleaning supplies, personal care products, paint, pesticides, and more.

Choose office supplies, furnishings, and other products with low (or no) chemical emissions to limit pollutants in their indoor airspace.

“We need to make better decisions about the products we put into our homes—low VOCs, no pesticide use, and purchasing furniture without flame retardant chemicals,” said Allen, who is also the director of the Healthy Buildings Program at Harvard, where he investigates the connections between indoor air quality and health.

Unfortunately, many products are also made with chemicals that are emitted into the air in the form of gas—a process known as off-gassing. Because of the impact of these off-gassing chemicals on air quality, Allen urges consumers to choose office supplies, furnishings, and other products with low (or no) chemical emissions to limit pollutants in their indoor airspace.


Making matters worse, our homes, schools, and offices are often built in such a way that toxic chemicals get trapped inside, concentrating in our air space. A lack of ventilation is one of the biggest reasons indoor air quality is so poor, and modern building methods are to blame, Allen says.

Airflow was always an important consideration for previous generations of architects. But starting in the 1970s, builders began creating spaces that were more tightly sealed. Since 2000, there has been an even greater effort to ensure that our buildings remain air tight.

This design choice makes for structures that are more energy efficient and fireproof, but it inevitably hurts air quality for the people who live and work inside, leading in severe cases to what is known as sick building syndrome.

I think it’s a false choice that we’ve been presented with for a long time: energy versus health. In fact, we should have both and we can have both.

— Joseph Allen

With minimal ventilation, air can’t circulate. Pollution concentrates indoors, and, by design, there’s little exchange of fresh air brought from outside. As a result, people who reside in “sick buildings” may develop eye irritation, headaches, breathing problems, and other health issues.

Virtually every building we inhabit—from the coffee shop you visited this morning to the place you’re reading this article right now—is governed by this minimal ventilation standard.

Several studies have shown that people who live, work, or attend school in buildings with good air circulation are healthier and more productive than those who inhabit poorly ventilated spaces. One study conducted in California found that students felt calmer and had longer attention spans in highly ventilated classrooms.

Studies have also demonstrated a relationship between poor ventilation rates and higher instances of short-term sick leave, asthma, and respiratory infection among building occupants.

In the interest of keeping energy costs down, most builders still tend toward minimal ventilation. But Allen says we spend too much time indoors to live and work in spaces that sacrifice our health.

“I think it’s a false choice that we’ve been presented with for a long time: energy versus health. In fact, we should have both and we can have both,” he said.

More Ways to Improve Air Quality

We can’t see or smell many of the chemicals that pervade our environment. Besides chemically sensitive individuals, most of us don’t think about our indoor air space until someone gets sick. Even then, we may still not link our health problems to air quality.

But we can take simple precautions to ensure that our inside air is as clean as can be.

In addition to improving ventilation and limiting exposure to toxic off-gassing chemicals, be sure to employ simple public health measures. “Wash your hands, and take your shoes off so you’re not tracking in outdoor pollutants into your home,” Allen said.

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Another step is controlling exposure to fine particles in your environment. One way in which we create these particles is cooking. That’s why Allen recommends installing an exhaust system over your stove.

“You want exhaust ventilation that is capturing those pollutants and putting them outside,” he said. “A lot of the time, they’re just putting them right back into your breathing zone.

To collect these fine particles while cleaning, use a vacuum with high efficiency particulate air (HEPA) filtration. “Very often when people use a vacuum, it doesn’t capture the particles, it just disperses the particles and turns them into smaller particles. So you can actually increase the exposure,” Allen said.

The good news is, making these small improvements can have a big impact. Last year, Allen and his team published a study that examined how the indoor environment impacts our ability to think and process information. Researchers had people come into a controlled environment, and each day made various changes to the air the participants’ breathed, then tested their cognitive functions.

“Even with minor improvements in the environment, we saw better cognitive function scores,” Allen said.

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