health

Feb 22, 2016

Cleaner Air Means Healthier Hearts

Air Pollution, Clean Air, health, healthy heart month, heart, heart attacks, Million Hearts, science, strokes 25 Comments

By EPA Administrator Gina McCarthy

February is Healthy Heart Month. There’s no better time than now to learn how to protect your heart.

Air pollution can affect heart health, and even trigger heart attacks and strokes. That’s important information for the one in three Americans who have heart disease, and for the people who love them.

And it’s why EPA is working with other government agencies, and with private and nonprofit health organizations, on the Million Hearts® national initiative to prevent 1 million heart attacks and strokes by 2017. This month, and every month, we want to make sure people understand how heart disease is linked to air pollution – and what people can do to protect themselves.

Scientific studies, including research by EPA scientists, shows that there’s not just an association between air pollution and heart disease, but that this association can have life-threatening consequences.

In a recent study in Environmental Research, EPA scientists looked at data from NASA satellites and EPA ground-based air monitors, and confirmed that heart disease and heart attacks are more likely for individuals who live in places with higher air pollution. The study found that exposure to even small additional amounts of fine particle pollution averaged over a year could increase a person’s odds of a heart attack by up to 14 percent.

So, what can you do to help keep your heart healthy?

You can start by making sure to eat nutritious meals and exercise (just make sure to check with your health care provider first).

Check the Air Quality Index every day to learn about your local air quality and how can reduce your exposure to air pollution.

And we can all do our part to make choices that are better for the environment and our health – like taking public transit more often and driving cleaner vehicles.

This February, and every month, remember that cleaner air means healthier hearts.

Editor's Note: The views expressed here are intended to explain EPA policy. They do not change anyone's rights or obligations. You may share this post. However, please do not change the title or the content, or remove EPA’s identity as the author. If you do make substantive changes, please do not attribute the edited title or content to EPA or the author.

EPA's official web site is www.epa.gov. Some links on this page may redirect users from the EPA website to specific content on a non-EPA, third-party site. In doing so, EPA is directing you only to the specific content referenced at the time of publication, not to any other content that may appear on the same webpage or elsewhere on the third-party site, or be added at a later date.

EPA is providing this link for informational purposes only. EPA cannot attest to the accuracy of non-EPA information provided by any third-party sites or any other linked site. EPA does not endorse any non-government websites, companies, internet applications or any policies or information expressed therein.

Oct 2, 2015

Explaining How We Address Contaminated Sites – Learn About the Superfund National Priorities List

cleanups, health, national priorities list, npl, reuse, superfund 0 Comments

By Mathy Stanislaus

Love Canal. Valley of the Drums. In the late 1970s, these sites created a growing national awareness that if hazardous waste was released into the environment and left abandoned, it presented potential human health and environmental risks. On December 11, 1980, President Jimmy Carter signed the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA, better known as “Superfund”) into law. Finally, the federal government had a statutory authority to clean up sites where releases had occurred or threatened to occur.

EPA maintains a list of the nation’s most serious abandoned and uncontrolled hazardous sites, the National Priorities List (NPL). The NPL helps us determine which sites warrant further investigation and cleanup. There is a statutory requirement to update the NPL annually, though as a matter of policy, we typically update the NPL twice a year. Recently, we added five and proposed seven hazardous waste sites to the NPL.

Only sites on the NPL are eligible for federal funding for long-term cleanup. The Superfund program operates on the principle that polluters should pay for the cleanups, rather than passing the costs to taxpayers. We search for parties legally responsible for the contamination at sites and the law holds them accountable for the cleanup costs. For the newly added sites without viable potentially responsible parties, we will investigate the full extent of the contamination before starting substantial cleanup at the site.

We undertake removal actions to address more immediate threats, including emergencies that require on-scene arrival within hours, and time-critical situations, where a response is needed within six months. Removal actions may speed up the cleanup of portions of a site or eliminate the need for long-term actions at portions of a site.

Listing a site on the NPL is a multi-step process. To propose a site to the NPL depends on many factors such as:

site complexity;
extent of stakeholder interest;
state and tribal support; and
availability of other cleanup options.

After initial investigation and sampling determines the site warrants further evaluation and potential remediation, the data gathered is used to evaluate a site’s relative threat to human health or the environment through the Hazard Ranking System.

In addition, if the Agency for Toxic Substances and Disease Registry (ATSDR) issues a health advisory recommending removing people from the site and we determine it will be more cost-effective to use our remedial authority rather than our emergency removal authority, a site can be placed on the NPL. Further, each state can designate one top-priority site for addition to the NPL (16 states or territories have yet to designate a top-priority site). Sites are proposed for addition to the NPL as a rulemaking published in the Federal Register. EPA generally accepts comments for 60 days, responds to the comments, and places those sites on the NPL.. For most sites, the time between proposal and final listing is six months.

State partnership is critical to the cleanup of Superfund sites. We often work with states to conduct site assessments, and as a matter of policy, we request state support to place sites on the NPL. In some cases, states lead the remedial action work with our oversight. As a statutory requirement, states contribute a “cost share” equal to 10 percent of the fund-financed costs of the remedial action, and are responsible for long-term operation and maintenance of the site remedy. When we list sites on the NPL, federally recognized tribes are afforded the same treatment as states at sites for which they have jurisdiction.

Superfund cleanups protect communities’ health, environment and economic wellbeing. The study Superfund Cleanups and Infant Health, shows that investment in Superfund cleanups reduces the incidence of congenital abnormalities in infants by as much as 25 percent for those living within 2,100 yards of a site. Another study found that once a site has all cleanup remedies in place, nearby property values reflect a significant increase as compared to their values prior to the site being proposed for the NPL.

Superfund not only protects health and the environment, it can serve as a catalyst for beneficial reuse. Today hundreds of communities are reusing Superfund sites for ecological, recreational, industrial, military, commercial, residential, and other productive uses. At the end of FY 2014, based upon data from 450 of the of the 850 sites that have some type of reuse, ongoing operations of more than 3,400 businesses are generating sales of more than $30 billion and employing over 89,000 people representing a combined income of $6 billion.

Apr 2, 2013

My Air, My Health, My Future

air research, air sensors, asthma, health, health datapalooza, innovation, My Air My Health, sensor apps, smartphone apps 6 Comments

The best innovations rely on disruption, a catalyst for change in a world of status quo.

Disruptive innovation is the theory behind the My Air, My Health Challenge, sponsored by EPA and the Department of Health and Human Services (HHS). The challenge encouraged Americans to consider the future of air quality and human health by developing small, wearable air quality sensors that also detect how our bodies respond to the air we breathe.

Two major ideas drive the effort to combine air sensor technologies and health data. First, sensors mirror the rise of computers and smartphones – more power in less space at lower prices. Second, the air we breathe affects our health, but that data changes constantly as we move.

All four finalist teams in the challenge received $15,000, and the teams continue to transform their designs into portable sensor systems that measure air quality and corresponding physiological responses to that air quality.

Below, leaders of the four teams talk about how they’re pursuing the priorities of sensor portability, data accuracy, and low cost for the final design.

Aaron Hechmer and his team chose to focus their challenge efforts on the aspects of air sensor data and cost. “This project, it really is sharing health information. To make [sensors] statistically robust, they’ve got to be in a lot of hands. To be in a lot of hands they’ve got to be cheap, particularly if you’re trying to serve communities. People don’t want to pay $5,000.”

Michael Heimbinder leads a team designing an air sensor that measures fine particulate matter and carbon monoxide. The team uses a chest strap sensor to look for connections between air pollutant exposure and heart rate variability, the interval between heart beats. The team completed a first prototype air monitor and will build five more for volunteers to wear and collect data. Heimbinder says the next hurdle is visualizing the data by “displaying thousands and thousands of measurement points as dots on a map.”

Guy Shechter and his team view the long-term scientific prospects of the challenge. The team’s sensor will tease out links between ultrafine particulate pollution and obstructive respiratory diseases such as COPD and asthma. “The exciting thing for us is this lack of science in this area and our belief that with the technology we have, with the scientific minds we have thinking about this, that we can actually do something interesting and new.”

David Kuller’s team has created T-shirts sewn with sensors. Owners can wash the shirts as long as they remove the battery and the air sensor, about the size of a matchbox, prior to washing. To measure health indicators, the shirts use an elastic strip of silver yarn that was originally designed for monitoring newborn babies. “We knew about the existence of these stretch sensors but hadn’t put them to test in any laboratory way.”

Stay tuned for an update this summer. The challenge winner will receive an award of $100,000 to be announced in June 2013 at Health Datapalooza IV.

About the author: Dustin Renwick works as part of the innovation team in the EPA Office of Research and Development.

Editor's Note: The opinions expressed herein are those of the author alone. EPA does not verify the accuracy or science of the contents of the blog, nor does EPA endorse the opinions or positions expressed. You may share this post. However, please do not change the title or the content. If you do make changes, please do not attribute the edited title or content to EPA or the author.

EPA's official web site is www.epa.gov. Some links on this page may redirect users from the EPA website to a non-EPA, third-party site. In doing so, EPA is directing you only to the specific content referenced at the time of publication, not to any other content that may appear on the same webpage or elsewhere on the third-party site, or be added at a later date.

EPA is providing this link for informational purposes only. EPA cannot attest to the accuracy of non-EPA information provided by any third-party sites or any other linked site. EPA does not endorse any non-government websites, companies, internet applications or any policies or information expressed therein.

Oct 19, 2012

Science Matters: Closing the Asthma Gap

air quality, asthma, asthma disparities, children's environmental health, children's health, Children's Health Month, health, health disparities, kids health, minority children, wildfires 1 Comment

To observe October as Children’s Health Month, we will periodically post Science Matters feature articles about EPA’s children’s health research here on the blog. Learn more about EPA’s efforts to protect children’s health by going to www.epa.gov/ochp.

Nearly 26 million Americans, including seven million children, are affected by asthma. But when emergency room doors burst open for someone with an asthma attack, chances are the patient will be a poor, minority child.

According to the Centers for Disease Control and Prevention (CDC), minority children living in poor socioeconomic conditions are at greatest risk. For instance, 16% of African American children had asthma in 2010 compared to 8.2% of white children, and they are twice as likely to be hospitalized with an asthma attack and four times more likely to die than white children. The asthma rate among children living in poverty was 12.2% in 2010, compared to 8.2% among children living above the poverty line.

“Across America we see low-income and minority children and families at a disproportionately higher risk for asthma and respiratory illnesses. Air pollution and other challenges are having serious health effects, which compound economic challenges through medical bills and missed school and work days,” said EPA Administrator Lisa P. Jackson. “As the mother of a child with asthma, I know what it means for our children to have clean and healthy air to breathe.”

Administrator Jackson made those remarks during the unveiling of the Coordinated Federal Action Plan to Reduce Racial and Ethnic Asthma Disparities, a blueprint for how EPA and other federal agencies can team up to reduce asthma disparities.

A major part of that effort is the work conducted by EPA scientists and their partners exploring environmental causes and triggers of asthma, including how socioeconomic factors contribute to childhood asthma. The overall goal is to illuminate the underlying factors of asthma to support work on prevention and intervention strategies.

What increases the risk of developing asthma? While part of the answer certainly lies with genetics, as more than half of all children with asthma also have close relatives with the illness, the environment also plays a key role. Air pollutants, allergens, mold, and other environmental agents trigger asthma attacks.

EPA researchers and their partners are leading the effort to develop new scientific methods, models, and data for assessing how such triggers increase the risk for asthma and asthma attacks. The impact of this research has already contributed to current regulatory standards for two priority air pollutants regulated under the National Ambient Air Quality Standards (NAAQS): ozone and particulate matter. EPA’s asthma research has also been factored into health assessments for diesel emissions.

The next step is to learn ways to better protect those most at risk.

“Now we’re digging into the disparities side of the asthma problem,” said Martha Carraway, MD, a researcher at EPA. “Kids with poorly controlled asthma are more likely to be treated in the emergency room than kids with controlled asthma. So for public health reasons we need to understand how environmental factors, including air pollution, affect asthma control in vulnerable populations.”

To advance that work, EPA researchers and their partners took advantage of a 2008 lightning strike that occurred in Pocosin Lakes National Wildlife Refuge in North Carolina. The 40,000-acre (16,000-hectare), smoldering peat fire sparked by the lightning sent thick, billowing clouds of smoke wafting into the air.

In collaboration with scientists at the University of North Carolina Center for Environmental Medicine, Asthma, and Lung Biology, a team of EPA researchers led by David Diaz-Sanchez, PhD compared emergency room visits for asthma with air quality reports. Looking at the results geographically, they found that low income counties had significantly more visits than more affluent counties, even though air quality and exposure levels were the same.

Haga clic en la imagen para unirse a la conversación en nuestro blog en español... ¡No olvide de suscribirse!

“EPA studies suggest that children and others living in low-income counties could be less resilient to air pollution, possibly because of social factors such as inadequate nutrition. For example, if you’re poor and you’re not eating well, your asthma may be more severe,” said Nsedu Obot Witherspoon, MPH, Executive Director of the Children’s Environmental Health Network, a national multi-disciplinary organization whose mission is to protect developing children from environmental health hazards and promote a healthier environment. “Of course, other factors may also be involved, such as whether kids take medications correctly and whether they have access to good medical care.”

EPA’s research on asthma disparities can help guide newer and better interventions for reducing exposure to asthma triggers and limiting the impacts of the ailment, helping to close the gap for minority and poor children and improving the health of children everywhere.

Sep 20, 2012

On the way to wonderful…

Arts, Brownfields, health, In Your Backyard, Local Community, Partnership, Philadelphia, Stormwater, Urban Waters 0 Comments

By Maryann Helferty

Front of the Overbrook Environmental Education Center

During a summer drive along a busy commercial corridor in Philadelphia’s historic Overbrook section, I was transfixed by a vibrant mural lining the cinder block wall of a former cable manufacturing plant. The wall had been painted to show bees and flowers emerging over the cityscape just as the property’s new occupant, the Overbrook Environmental Education Center, has grown into a community asset from a former brownfields site.

Interpretive signs explained how stormwater systems in older cities are often routed in tandem with the sanitary sewer. During heavy rainfall, raw sewage can be discharged into waterways, causing a health concern. At this site, however, stormwater is managed with bio-retention basins, swales, green roof systems and pervious pavement. These techniques allow an amazing 90 percent of rainwater to be harvested on the 45,000 square foot site. Developers and contractors frequently visit to see these innovations in action.

The Center director, Mr. Jerome Shabazz, shared his vision for community-based urban outreach centers. “We create a third place beyond home and work, where everyone can meet and feel welcome.” How does creation like this happen? First, one listens to the home-owners and businesses to understand what strengths make Overbrook stable and connected. Then educational offerings build from the needs expressed by the community.

Overbrook Environmental Arts Orchard Planting

Today, like the bees on its mural, the former brownfields site hums with energy, offering environmental education initiatives, as well as nutrition, fitness, and literacy. Rising over the parking lot was the Penn State Extension High Tunnel Greenhouse; children are climbing a gym set under the trees; and a vibrant tile mosaic shows the creativity of residents from a Summer Youth project who designed the entrance that says: “On the way to wonderful find a place called alright.”

What are the strengths that make your neighborhood an alright place to be? How do you work in your community to make it wonderful? I’d love to hear from you.

About the Author: Maryann Helferty is a water quality scientist with the Mid-Atlantic Regional office of the EPA. She has worked on groundwater and watershed protection in both the rural Pacific Northwest and the urban corridors of the Atlantic. One of her passions is teaching urban youth about water through the poetry curriculum: River of Words.

Aug 10, 2012

Sister Blog: EPA Seeking Feedback on Beta Tool to Address Community Environmental Issues

C-FERST, communities, health, Sister Blog, sustainable and healthy communities 1 Comment

(Reposted from EPA’s Environmental Justice in Action Blog.)

By Dr. Valerie Zartarian and Dr. Andrew Geller

Communities and individuals are faced with exposure to many different kinds of pollution, like lead, air pollution, water pollution, and toxics in fish. People want to understand their health risks and how to prevent them. As communities move to protect their neighborhoods, the issues can seem too numerous, with too few experts and limited access to information that can limit meaningful involvement.

In EPA’s Office of Research and Development we are designing the Community-Focused Exposure and Risk Screening Tool (C-FERST) and related research to address these challenges. C-FERST is being developed to increase the availability and accessibility of science and data for evaluating impacts of pollutants and local conditions, ranking risks, and understanding the environmental health consequences of your community. (Keep reading at Environmental Justice in Action.)

Jul 25, 2012

You Don’t Need Oz to Give You a Healthy Heart

air research, health, Human Health, PECASE 1 Comment

By Christina Motilall

When the Tin Man went to the Wizard of Oz to get a heart, I am sure he assumed it was a healthy one. But as we all know, hearts are tricky things, affected by any number of stressors—including, EPA scientists are starting to learn, pollutants.

Everything from what we eat to what we breathe influences our heart in some way. That is why the research of EPA’s Dr. Mehdi Hazari analyzing air pollution effects on cardiovascular health is so important.

By researching and developing new methods to assess cardiopulmonary effects of air pollution, Dr. Hazari is working to ensure that we understand all of the cardiovascular effects our air may have on us. Dr. Hazari calls the effects he is studying ‘latent effects’—ones we cannot see the symptoms of right away, but can lead to subsequent adverse responses triggered down the road.

Dr. Hazari stated that his research has “demonstrated that two health-compromised groups might be more susceptible than healthy individuals: those with hypertension and those with heart disease.” It seems these days we all know someone struggling with heart-related problems, and Dr. Hazari’s research is working to understand what long-term role air pollution may play in this.

The big difference between Dr. Hazari’s research and others I have heard of is that he is not necessarily examining air pollution (specifically ground-level ozone and particulate matter) as a toxicant, but rather as a stressor. “Even though we are sometimes faced with these stressors on a daily basis, our bodies compensate for the insult and continue functioning normally. But have we considered the long-term implications? Because as the effects of these stressors accumulate in the body over time, our ability to compensate decreases and we run the risk of something adverse happening,” Dr. Hazari explains.

And the big picture of Dr. Hazari’s work also means he gets a picture with the President. That’s right. This week he was one of two EPA scientists named as recipients of the 2011 Presidential Early Career Award for Scientists and Engineers (PECASE). Next week, Dr. Hazari gets to travel to Washington, DC to meet the Commander-in-Chief and accept this prestigious award for innovative and internationally-recognized research. When asked how he felt about meeting the President, Dr. Hazari stated “It’s a once-in-a-lifetime opportunity, a total honor!”

Along with President Obama, I value Dr. Hazari’s future-focused research illuminating risks to protect the heart health of myself and my loved ones. And you know what? I bet if the Tin Man were here, he would wholeheartedly agree.

About the author: Christina Motilall is an intern for the Office of Research and Development’s Science Communications Team.

Jul 19, 2012

A Better Approach to a Clogged Drain?

chemicals, Drains, Green Solutions, health, In Your Backyard, Water Sense, What you can do 1 Comment

By Laura Janson

It happens every so often. One of the drains in my house gets clogged. It is usually the drain in my shower stall or the drain in my bathroom sink. They tend to collect hair.

Being a health-conscious environmentalist, I try not to use harsh chemicals — you know — the ones that contain an irritant that can burn your skin or the inside of your nose? I’ve tried a drain snake, but that requires some elbow grease and sometimes I can’t seem to reach the clog. Why don’t I just use a drain sieve or filter on top of the drains? The bathroom sink is angled so that one will not lay flat. I did find one for the shower that’s easy to clean—stainless steel—and is fine enough to catch hair, but it doesn’t fit in the kids’ tub. What about an environmentally friendly drain cleaner? Good approach, but let’s think outside of the box.

An idea hit me when my brother showed me the filter in my dishwasher that catches large food particles and “foreign objects” like fancy plastic toothpicks. Who knew? Not me, but then I never read the entire manual.

Why not have the same gizmos, those traps they have in many dishwashers, in bathroom drains? Then I could just unscrew the cover on the drain, pull out the trap, remove the hair, put back the cover, and voila, an unclogged drain! It would just take a minute and it would be environmentally friendly.

Calling all faucet manufacturers or entrepreneurs. Find a way to incorporate a filter into every faucet’s design. Then everyone can clean their own drain filters. . . they just have to read the manual to know it’s there.

While you’re thinking about eco-friendly bathroom fixtures, check out all the water efficient appliances from the Water Sense program. Will you be giving your bathroom an eco-makeover?

Jun 26, 2012

Ozone Exposure and Your Heart

Air, air research, health, ozone 6 Comments

By Jing Zhang

I couldn’t imagine living in a world where buildings are filled with thick cigarette smoke, but smokeless buildings haven’t always been the norm. Many things today, such as washing hands to avoid spreading germs, were previously not the norm and are the result of scientific findings uncovered years ago.

EPA researchers and scientists are constantly conducting studies to make important advances in improving human health and the environment. One such EPA study was recently published in the American Heart Association journal Circulation. (Read the press release.)

According to the study, breathing in ozone can be harmful to both your lungs and your heart.

For years, air pollutants, including ozone, have been known to harm the lungs. The EPA ozone study shows that breathing in ozone can cause inflammation of the vascular system, a change in heart rate variability, and a reduction in the ability of blood clots to dissolve, which are risk factors for heart disease. The study also confirmed the ability of ozone to impact lung inflammation and function.

It amazes me how a seemingly simple molecule composed of three tiny oxygen atoms can impact lung and heart health! Where does this tiny yet harmful air pollutant come from?

As it turns out, ozone is in two areas of the earth’s atmosphere. Ozone exists naturally in the upper regions of the atmosphere, where it protects the earth from the sun’s harmful ultraviolet rays. Ozone found at the ground level is created from the mixture of nitrogen oxides (NO_x), volatile organic compounds (VOC), and sunlight. The NO_x and VOC emissions come from sources including industrial facilities, electric utilities, and vehicle exhausts.

Because sunlight is a key factor in creating ground-level ozone, sunny days can create unhealthy levels of ozone in urban areas. Some people, including children, older adults, and those with preexisting heart or lung conditions, are at greatest risk from exposure to ozone.

In order to protect your health, use EPA’s Air Quality Index, which forecasts air quality on a daily basis, and minimize time spent outside on high ozone days.

The recently-released EPA study paves the way for further research on the health effects of exposure to ozone. With more discoveries, the impacts of ozone on health may become as widely known as the impacts of cigarette smoke on health. In the meantime, EPA scientists are continuously conducting cutting-edge research to protect your heart from outdoor air pollution and environmental effects.

To learn more about EPA air research, vistit: www.epa.gov/airscience

About the author: Jing Zhang is a student services contractor working on the Science Communications Team in EPA’s the Office of Research and Development.

Jun 6, 2012

Attention Innovators: The My Air, My Health HHS/EPA Challenge is Open!

air research, health, innovation, My Air, My Health 4 Comments

By Ruthanna Gordon

When I came to work for EPA as an American Association for the Advancement of Science fellow, I hoped to connect my social science background with my passion for the environment. In my time on EPA’s Innovation Team, I’ve found such connections in places I never expected. I’ve grown particularly excited about our work on portable air quality sensors.

As a psychologist, I have learned that people care about a problem more, and come up with better solutions, when they see how it affects them personally. Air pollution is a great example—when people can measure particulates on their jogging route, it’s far more meaningful than just hearing about the issue on the news.

The My Air, My Health Challenge, announced today by EPA’s Science Advisor Dr. Glenn Paulson and Dr. Linda Birnbaum of the National Institute of Environmental Health Science, aims to gather the best work in this area, and bring it to the next level.

The challenge calls on academics, industry researchers, and garage-lab do-it-yourselfers to connect wearable air and health sensors, allowing citizens and communities to collect highly localized data and create a meaningful picture of how the environment affects their well-being.

The data integration and analysis component of the challenge is particularly exciting.

A few weeks ago, I was privileged to attend the Apps and Sensors for Air Pollution workshop in Research Triangle Park, NC. There, I listened to cutting edge sensor developers talk about their work. They had some fascinating projects, ranging from cheap ozone monitors carried by students to a community initiative measuring black carbon in the homes of elders. Our challenge took its final shape from these experts’ input.

Portable sensor development is flourishing, but everyone agreed that integrating data from different types of sensors was a tough problem that needed an extra push to move forward. My Air, My Health is intended to be that push. It spotlights the problem—and gives researchers an extra incentive for focusing on it. The four top ideas will receive $15,000 apiece, and be invited to carry out a proof-of-concept project in the 2^nd phase. The best of these projects will receive a grand prize of $100,000.

If you’d like to hear more about the My Air, My Health challenge, or if you know an innovative thinker who might be interested in participating, we’re holding a webinar on June 19^th at 4 PM. We’re looking forward to seeing what everyone comes up with!

About the Author: Ruthanna Gordon is a behavioral scientist, and a AAAS science and technology fellow working with the EPA Innovation Team.

1 2