Pollution & Health
10 Apr 2014:
Mapping Program Helps
Cities See Money Saved by Planting Trees
New open-source software is helping cities better understand the benefits trees provide by calculating the value of the trees' ecosystem services, such as air quality improvements and CO2 storage. More than a dozen
cities have undertaken tree inventory initiatives, thanks to the OpenTreeMap software
, and residents have helped map more than 1.1 million trees worldwide. In addition to plotting a tree's location, users record its size, species, and other parameters that allow the software to calculate the tree's ecological value in terms of dollars saved through such benefits as cleaner air. San Diego's more than 340,000 mapped trees
, for example, are estimated to provide the city more than $7 million in benefits each year, including $4 million in air quality benefits and $2 million in reduced energy costs. In the coming months, the software will allow city managers to decide where to plant trees for maximum environmental benefit.
07 Apr 2014:
Newfound Atmospheric 'Hole'
Threatens Polar Ozone Layer, Scientists Say
Researchers have discovered
a large opening in the Earth's atmosphere that is enabling pollutants to rise
Pacific atmosphere hole an elevator to the stratosphere
into the stratosphere and destroy ozone. The hole, which is in a part of the lower atmosphere called the "OH shield," is several thousand kilometers long and is centered over the tropical west Pacific Ocean. It's relatively close to Southeast Asia, a region with a booming population and rapidly increasing air pollution. The hole is a major concern because the OH shield usually scrubs air of chemical compounds emitted near the ground before they can reach the stratosphere, where those compounds can persist for long periods of time, reacting with and destroying ozone, say researchers at Germany's Alfred Wegener Institute who identified the hole. The newly discovered phenomenon acts as a sort of elevator, researchers say, drawing chlorofluorocarbons, sulfur dioxide, and other contaminants straight up to the stratosphere and bypassing the OH shield scrub.
E360 Announces Contest
Yale Environment 360
For Best Environmental Videos
is holding a contest to honor the best environmental videos. Entries must be videos that focus on an environmental issue or theme, have not been widely viewed online, and are a maximum of 15 minutes in length. The first-place winner will receive $2,000, and two runners-up will each receive $500. The winning entries will be posted on Yale Environment 360
. The deadline for entries is June 6, 2014. Read further contest information.
01 Apr 2014:
Delaware River Watershed
Is Focus Of Large-Scale Restoration Project
A Philadelphia foundation is providing $35 million to launch a host of programs aimed at better protecting the Delaware River
, which flows through the heart of
Delaware River at Trenton, New Jersey
the populous U.S. eastern seaboard and provides drinking water for 15 million people. The William Penn Foundation, working with nonprofit groups such as The Open Space Institute, says its Delaware River Initiative will protect more than 30,000 acres of land, launch 40 restoration projects, create incentives for businesses and landowners to protect the watershed, and set up a comprehensive program of water quality monitoring that will enable the foundation and its partners to measure the success of their programs and the overall health of the river. A cornerstone of the foundation’s initiative will be its restoration and protection work in eight so-called “sub-watersheds” that feed into the Delaware River.
12 Mar 2014:
Nine Chinese Cities Outpaced
Beijing in Air Pollution in 2013, Report Says
China's air pollution problems are more severe and widespread than previously thought, with nine cities experiencing more days of extreme air pollution than Beijing in 2013, according to
a new analysis by Greenpeace's Energy Desk. Fine particulate (PM2.5) pollution plagued dozens of cities and millions of people in China — most of them outside of Beijing, although the Chinese capital captured the most air pollution headlines last year. The city of Xingtai, southwest of the capital, fared worst, with 129 days of emergency air pollution — more than doubling Beijing's 60 days. More than half of the cities in the top 10 are in Hebei province south of Beijing, where many steel, cement, and coal-fired power plants are located. "There are now millions of Chinese people living in cities with air pollution above emergency levels for a third of the year, while other urban areas have gone a whole 12-month period with hardly any days of good-quality air," said a member of Greenpeace's East Asia climate and energy campaign. Beijing had only 13 days ranked as "good" on the U.S. air quality scale, along with one day considered "beyond index," or off the pollution scale.
10 Mar 2014:
Arsenic Remediation Project
Will Begin Decontaminating Water in India
New technology that removes arsenic from drinking water is set to be deployed on a large scale in India, according to
researchers from Lawrence Berkeley National Laboratory and an India-based water technology company. The device removes arsenic by passing electricity through steel plates submerged in a water reservoir. The electric current causes the plates to rust more quickly than they would under normal conditions, and the rust chemically binds to arsenic in the water and sinks to the bottom of the reservoir. The precipitated sludge can be removed from the tank, rendering the water safe to drink. Notoriously high levels of arsenic, a tasteless and odorless contaminant, naturally occur in groundwater sources in India, Bangladesh, and even California's Central Valley. Long-term exposure can cause cancer and severe damage to organs. A commercial plant is set to begin operations in West Bengal, India, this year and researchers estimate the drinking water can be sold for as little as eight cents per gallon.
24 Feb 2014:
Maps Show Extent of
Oil and Gas Drilling in Southwest Wyoming
Oil and gas wells, including those involved in hydraulic fracturing operations, scar a major portion of southwest Wyoming, according to a recent analysis by the U.S. Geological Survey
. Nearly 17,000 well pads and former
drilling areas associated with oil and natural gas production were identified in satellite images across a 30,000-square-mile region. The maps include well scars dating from around 1900, when oil drilling started in the region, up to 2009, at which point natural gas extraction far outweighed oil production. Since then, production has only intensified in Wyoming, a leading state in the U.S.'s unconventional oil and gas boom. The mapping effort, a first step in determining how oil and gas drilling operations impact wildlife and ecosystems, focused on southwestern Wyoming because it not only has some of the nation's largest natural gas reserves, but also because the region has high-quality wildlife habitat and encompasses a major portion of the country's remaining intact sagebrush steppe.
21 Jan 2014:
More Crude Oil Spilled by
U.S. Trains in 2013 Than Previous 40 Years
U.S. trains spilled 1.15 million gallons of crude oil in 2013 — more than was spilled in the nearly 40 years since officials began tracking such accidents, federal data show
. The majority of that volume came from two major derailments: a November incident in Alabama that spilled 750,000 gallons and a December incident in North Dakota that officials estimate spilled 400,000 gallons. Those incidents, as well as smaller spills, have added to growing concerns over the safety of using railways
to transport crude as U.S. oil production surges in the upper Midwest. From 1975 to 2012, a total of 800,000 gallons of crude were spilled during rail transport. Excluding the two major derailments from the 2013 total, 11,000 gallons of crude were spilled last year — more than the previous two years combined. The data do not include a 1.5 million-gallon spill that killed 47 people in Lac-Mégantic, Quebec, in July.
16 Jan 2014:
Pebble Mine Would Endanger
Alaska's Bristol Bay, Major EPA Study Finds
A three-year study by the U.S. Environmental Protection Agency (EPA) has determined that mining in Alaska's Bristol Bay area would pose significant dangers to the environment
, a potentially fatal setback for plans
Mulchatna River, part of Bristol Bay watershed
to develop Pebble Mine, a major open-pit mining project that aimed to exploit one of the largest and richest mineral deposits in the world. The EPA study cited concerns for the region's thriving sockeye salmon population
and its native people, saying the mine would destroy 24 to 94 miles of salmon streams and 1,300 to 5,350 acres of wetlands, ponds, and lakes. Pebble Mine proponents, including Alaska Governor Sean Parnell, criticize the study as flawed and rushed, since the development company wasn't allowed to submit its mining plan before the EPA study. Native groups, fishermen, and environmental organizations are applauding the study. The proposed mine — which seeks to exploit gold, copper, and other metals — was already in trouble, with one of two major partners withdrawing from the project last year.
Interview: Activist Kumi Naidoo
On Russia and the Climate Struggle
Kumi Naidoo, the international executive director of Greenpeace, is intimately familiar with the Prirazlomnaya drilling platform in the Russian Arctic. In 2012, he and five other Greenpeace activists were hosed down with frigid water and pelted with pieces of metal as they attempted to climb aboard the platform.
Greenpeace and Prirazlomnaya were back in the news recently when 28 Greenpeace members were arrested and held for several months for storming the rig before being released in December. In an interview with Yale Environment 360
, Naidoo talks about what’s needed to get global climate talks off the ground and launch a green energy revolution, and the reason his activist organization has decided to take such a strong stand against oil drilling in the rapidly melting Arctic Ocean. "We went back [to Prirazlomnaya]," says Naidoo, "because we’re trying to draw a line in the ice, because once this starts it will have breached another threshold of meeting our rapacious appetite for oil and gas in the most fragile of environments." Read the interview.
10 Jan 2014:
Natural Gas Has Sharply
Reduced Emissions from Power Plants
The dramatic increase in using natural gas to produce electricity in the United States has led to an equally dramatic decline
in the amount of pollutants and carbon dioxide emitted from the nation’s power plants, according to a new study. The study, conducted by researchers at the National Oceanic and Atmospheric Administration, showed that the switch from coal-fired to natural gas-fired power plants has reduced CO2 emissions by 23 percent and emissions of nitrogen oxides and sulfur dioxide by 40 and 44 percent, respectively. Examining power plant emissions from 1997 to 2012, the scientists found that new combined-cycle natural gas-fired power plants — which use two heat engines in tandem to convert a higher fraction of heat into electrical energy — emit less than half the amount of CO2 as coal-fired power plants. The study, to be published in the journal Earth’s Future
, said that the fraction of electricity produced in the U.S. from coal fell from 83 percent in 1997 to 59 percent in 2012. Meanwhile, the fraction of electricity generated by combined-cycle natural gas plants rose from zero to 34 percent.
08 Jan 2014:
China Approves Major
Increase in Huge Coal Mining Projects
In 2013, the Chinese government approved 15 large coal mining projects
that will produce more than 100 million new tons of coal a year. The expansion will lead to a 2 to 3 percent growth in coal production over the next several years, even as the country announced moves to reduce the severe air pollution
choking major cities such as Beijing. Chinese officials will increase coal production while reducing pollution in population centers by closing outdated coal plants and creating huge “coal bases” that will mine and burn coal in remote regions of northwestern China, such as Inner Mongolia. Those bases, which will cost $8.9 billion to build, will generate electricity that will be transferred over an improved electricity grid to cities in China’s central and eastern regions. Deng Ping, an environmental campaigner with Greenpeace, said the scale of the new coal bases is unprecedented for China, adding, “Despite the climate change pressure, water resource scarcity, and other environmental problems, the coal industry is still expanding fast in northwest China.”
03 Jan 2014:
North Dakota Bakken Crude
More Explosive Than Expected, Officials Say
Crude oil from North Dakota's Bakken field may be more flammable and explosive than previously thought
, officials now say after a series of fiery railroad accidents. The crude may contain more flammable gasses, be highly corrosive, or more sulfurous than crude from other oil fields, according to the Pipeline and Hazardous Materials Safety Administration (PHMSA). The agency is warning Bakken oil producers to "sufficiently degasify" the crude oil before loading it into rail cars. On Monday, several tank cars carrying Bakken crude exploded after a collision on a remote stretch of track in North Dakota, and last July a runaway train carrying the crude derailed and exploded in Lac-Mégantic, Quebec, killing 47 people. U.S. railroads have asked manufacturers for safety upgrades to tank cars
that carry Bakken crude, which could cost the industry roughly $3 billion, Reuters estimates. Trains carried nearly 700,000 barrels of Bakken crude each day in October, a 67 percent increase over the previous year.
Interview: A Legal Call to Arms to
Fix Environmental and Climate Ills
University of Oregon law professor Mary Wood has an unsparing view of the state of environmental protection in the United States today: On a host of fronts — from climate change to the nationwide fracking boom —
the federal and state governments are failing to protect ecosystems and resources vital to current and future generations. In an interview with Yale Environment 360
, Wood discusses why she believes the judiciary needs to step in to force the executive and legislative branches to protect natural resources that are part of the “public trust.” She also explains why she supports ongoing litigation to reduce carbon emissions under a related doctrine to safeguard the "atmospheric trust." Says Wood, "The political branches of government are doing next to nothing to address this crisis ... Across the board, agencies are not using the statutes to protect nature — they’re using statutes to permit damage to the environment."
Read the interview.
23 Dec 2013:
Russian Oil Giant Becomes
First in World to Pump Oil From Arctic
The Russian national oil company Gazprom has begun drilling for oil at a highly contested site in the Arctic
. The oil field, an offshore site in the Russian Arctic known as Prirazlomnoye, drew international attention in September when a contingent of Greenpeace members boarded the platform in protest and were jailed in Russia for two months before being granted amnesty last week. The project, which is several years behind schedule, is the first in Russian history aimed at "developing the resources of the Arctic shelf," Gazprom said. Environmental groups say that no company has the technology or resources to deal with a massive oil spill in the harsh conditions of the Arctic Ocean. The oil giant Shell had planned exploratory drilling in the Arctic off the coast of Alaska, but temporarily shelved those plans last year after a series of mishaps. Gazprom says it has taken all necessary precautions to deal with a spill, Mongabay reports.
Photo Essay: Documenting the Swift
Change Wrought by Global Warming
For 25 years, photographer Peter Essick has traveled the world for National Geographic
magazine, with many of his recent assignments focusing on the causes and consequences of climate change. In a Yale Environment 360
photo essay, we present a gallery of images he took while on assignment in Antarctica, Greenland, and other far-flung locales affected by climate change. View the photo gallery.
16 Dec 2013:
Volume of E-Waste
Projected to Soar by 2017, Study Says
The volume of electronic waste generated worldwide is expected to climb by 33 percent by 2017
to 65 million tons, according to a study conducted by a partnership of United Nations organizations, industry, governments, and scientists. So many computers, televisions, mobile
phones, and other devices are being tossed away annually that within four years the volume of e-waste would fill a 15,000-mile line of 40-ton trucks, the report
said. The report, released by a group called StEP
( Solving the E-Waste Problem Initiative) said that in 2012, 50 million tons of e-waste was generated worldwide, about 15 pounds for every person on the planet. China generated the most electronic waste last year, with 11.1 million tons, followed by the U.S. with 10 million tons. But in per capita generation, the U.S. dwarfed China and most other countries, with each American producing 65 pounds of e-waste, the study said. “The explosion is happening because there is so much technical innovation,” said Ruediger Kuehr, executive secretary of StEP.
10 Dec 2013:
Chinese State Media
Criticized for Touting Benefits of Smog
For Chinese citizens worried about smog, which has been blanketing major cities and smashing air pollution records recently, China's state media has some advice: Look on the bright side. State broadcaster CCTV and a Communist Party tabloid, Global Times
, yesterday published editorials
attempting to put a positive spin on China's air pollution crisis. The state-run outlets said smog has military benefits because it can interfere with the guidance systems of foreign missiles, as well as personal benefits such as bolstering Chinese citizens' sense of humor, making them more united, more sober, better informed, and more equal because smog "affected the lungs of both rich and poor," The Telegraph
reports. Internet commenters and other media outlets, including several state-run publications, were outraged. "Is the smog supposed to lift if we laugh about it?" asked the official publication Beijing Business Today
. The pro-smog pieces have both been deleted from the publications' websites.
06 Dec 2013:
China Doubles Pace
Of Renewable Energy Installation in 2013
Over the past 10 months China has added renewable energy sources to its power grid at double the pace of 2012, according to its National Energy Administration (NEA). The renewable energy push, part of a massive effort to cut air pollution in China's large cities, has added more than 36 gigawatts of clean energy capacity
Shanghai, Dec. 3, 2013
so far this year, Bloomberg News reports
. Hydroelectric power grew by 22.3 gigawatts in the first 10 months of 2013, new nuclear energy installations totaled 2.2 gigawatts, solar 3.6 gigawatts, wind 7.9 gigawatts. China's solar energy capacity could triple from 2012 levels to 10 gigawatts by the end of the year, while wind and nuclear power capacity could increase by 22 and 17 percent, respectively, the NEA said. That should offer some relief from China's choking air pollution. In Shanghai, schoolchildren were ordered indoors today
as air pollution reached extremely hazardous levels, exceeding World Health Organization health guidelines for fine particulate matter by 24 times.
03 Dec 2013:
Microplastic Pollution Harms
Worms at Bottom of Food Chain, Study Finds
As plastic trash accumulates in ocean ecosystems, it may be damaging worms and other sensitive marine life at the bottom of the food chain, scientists report. Two British studies found
that microplastics — tiny remnants, less than 5 mm in diameter, from the breakdown of plastic trash — made seafloor worms eat
Beach sediments churned by a lugworm
less and transferred pollutants from the plastics to the worms. Because they ate less, the worms had less energy to invest in important functions
such as growth, reproduction, and churning sediments, one of their most important roles in the ocean ecosystem. The worms also absorbed harmful chemicals from the debris
, including hydrocarbons, antimicrobials, and flame retardants, researchers said. Lugworms, often called the "earthworms of the sea," are considered an indicator species because they feed on ocean floor sediments. Microplastics have been accumulating in those sediments since the 1960s, and, although each particle is nearly invisible, taken together microplastics are the most abundant form of solid-waste pollution on the planet.
22 Nov 2013:
Majority of Americans
Uninformed About Fracking, Survey Finds
Most Americans are uninformed and lack opinions on hydraulic fracturing, or fracking, a process used to extract oil and gas from rock formations, a new survey says
. Fifty-eight percent of people surveyed specifically reported that they knew nothing at all about fracking, and the same percentage said they didn't know whether they supported fracking or opposed it. Seven percent said they were aware of some of the process's environmental impacts, and 3 percent said they knew of positive economic and energy supply impacts of fracking. Of those who held an opinion on it, 20 percent were opposed to fracking and 22 percent supported it. "Broadly speaking, our results paint a picture of an American populace that is largely unaware and undecided about this issue," the study says. The study
— conducted by researchers at Oregon State, George Mason, and Yale universities — was recently published in the journal Energy Policy
20 Nov 2013:
Low-Income Solar Project
Is Recognized at U.N. Climate Talks
An Australia-based solar start-up company was recognized at the U.N. climate change talks in Warsaw for its work replacing highly polluting kerosene lamps with solar lighting in low-income regions of India. The company, Pollinate Energy, trains members of local communities to install household solar-powered lights in India's slums, where families often rely on kerosene for lighting. So far the project has installed solar-powered lighting systems for 10,000 people in 250 of Bangalore’s slum communities, in turn saving 40,000 liters of kerosene and 100,000 kilograms of carbon emissions, RenewEconomy reports
. The solar lighting systems are cheaper to operate than kerosene lamps and are less polluting and dangerous than kerosene, which can cause house fires and severe burns. The nonprofit project started in Bangalore — home to some of India's worst slums — as a way for children to do schoolwork after sunset. Pollinate Energy trains local installers to distribute and install the lighting systems as micro-entrepreneurs, which they call "pollinators."
19 Nov 2013:
Pollution From Plastic Trash
May Make Tiny Island a Superfund Site
The U.S. Environmental Protection Agency plans to study whether plastic pollution on a small island in the Pacific Ocean is severe enough to warrant listing it as a Superfund clean-up site
. Tern Island, a 25-acre strip of land about 500 miles northwest of the Hawaiian island
Oahu, is home to millions of seabirds, sea turtles, and the endangered Hawaiian monk seal. The U.S.-based Center for Biological Diversity asked the EPA to add the entire Northwestern Hawaiian Islands and parts of the so-called Great Pacific Garbage Patch
to the list of federal Superfund sites due to extreme marine debris pollution, but the agency has only agreed to undertake an environmental study on Tern Island. The island is awash with debris ranging from plastic water bottles and bits of plastic to discarded fishing gear and home appliances. Studies have shown the trash can take a heavy toll on wildlife — seabirds, for example, often ingest bits of plastic after mistaking them for food and eventually die of starvation. The EPA study is the first step of a potentially years-long process to determine if the island qualifies for listing under the 1980 Superfund law.
13 Nov 2013:
Plastic Debris in Ocean
Has Spawned a 'Plastisphere' of Organisms
The plastic debris that litters the world's oceans has developed its own unique and diverse microbial ecosystem, researchers report. The microscopic community, which scientists dubbed the "plastisphere,"
includes more than 1,000 species of algae, bacteria, microscopic plants, symbiotic microbes, and possibly even pathogens, the researchers say in Environmental Science & Technology
. Some of the plastisphere microbes, many of which had never before been documented, contain genes that could help break down hydrocarbons, indicating the microbes may play a role in degrading the debris, the research shows. Plastic trash is the most abundant type of debris in the ocean, inflicting harm on fish, birds, and marine mammals that are entangled by it or ingest it. Until now, researchers hadn't looked at microbes living on the debris, which make up a sort of artificial "microbial reef," one of the scientists said
07 Nov 2013:
Grand Canyon 'Zombie'
Uranium Mine on Hold for Financial Reasons
The reopening of a major uranium mine near the Grand Canyon has been put on hold until December 2014 or whenever a federal court rules on the proposed revival of the mine, the Guardian reports
. The owner of Canyon
Grand Canyon's South Rim
Mine, Energy Fuels Resources, cited falling uranium prices, which have reached a near five-year low, and litigation costs as reasons for the decision. In April the Canyon Mine and other so-called "zombie mines"
were given federal approval to reopen based on their rights at the time they closed, despite an Obama administration ban on new hard-rock mines in areas larger than 1 million acres. Grand Canyon National Park officials say reopening the Canyon Mine, located six miles from the popular South Rim entrance, and other uranium mines could affect scarce water sources in the area. Environmental groups and the Havasupai Indian tribe sued the U.S. government in 2012, contending the environmental review of the mine's impacts was outdated.
05 Nov 2013:
Beijing To Limit New Cars
By 40 Percent in Anti-Pollution Drive
In an effort to reduce severe air pollution in the Chinese capital, Beijing will limit by 40 percent the number of new cars sold annually for the next four years, cutting license plate allocations from 240,000 to 150,000 each
Chang'an avenue in Beijing
year. The cap, which should also help ease the capital's worsening traffic congestion, means Beijing will license only 600,000 new cars between 2014 and 2017 — fewer than in 2010 alone, Reuters reports
. By 2017, 40 percent of those licenses, which drivers vie for in auctions and lotteries, will be reserved for hybrid and electric cars. New car sales in China are currently capped in four cities — Beijing, Shanghai, Guangzhou, and Guiyang — and the government plans to limit sales in eight additional cities, the China Association of Automobile Manufacturers said.
30 Oct 2013:
Low on Natural Gas, China
Cities Will Face Choking Air Pollution
In a push to curb air pollution, China has been urging its cities to rely more heavily on natural gas and less on coal. But a shortage of natural gas is threatening that goal, as urban populations boom and domestic gas production lags, Reuters reports
. Chinese officials have said that to reduce air pollution the most densely populated parts of Beijing should use only gas heat, which limits the supply of natural gas for smaller cities and forces those cities to rely on coal. Pollution levels in Chinese cities commonly exceed World Health Organization guidelines by 40 to 50 times. The problem is most pronounced in northern China, where air pollution from burning coal has already shortened life expectancy by 5.5 years compared to the southern part of the country. China's natural gas shortage is expected to be 10 percent higher this year than last year, since more users have switched from coal. Authorities are rationing natural gas and prioritizing its use for homes and transportation, but experts don't expect the shortage to subside anytime soon.
Photo Essay: Focusing a Lens on
China's Environmental Challenges
Photographer Sean Gallagher has lived and worked in China for seven years, visiting nearly all of its provinces as he documents the country’s daunting ecological problems and its widely varied landscapes. In a Yale Environment 360 photo essay
, the Beijing-based photojournalist chronicles China’s widespread water and air pollution, the battle against the desertification that has spread across the country's northern regions, and the threats to the nation's biodiversity.
View the photo gallery.
15 Oct 2013:
Nine in 10 Europeans in Cities
Breathe Dangerous, Polluted Air, Study Says
More than 90 percent of Europeans living in cities are exposed to harmful levels of air pollutants, according to a new assessment
from the European Environment Agency. Concentrations of ground-level ozone, or smog,
pose a danger to 97 percent of city populations, and levels of fine particulate matter (particles with a diameter less than 2.5 microns, known as PM2.5) exceed European standards for 91 to 96 percent of city-dwellers — and European standards for both pollutants exceed World Health Organization
recommendations. A new study of European mothers linked higher PM2.5 exposure
to lower birth weight, a standard indicator of fetal development. Eastern European countries have the highest levels of PM2.5, whereas ground-level ozone is worst in northern Italy. Although emissions of most air pollutants have steadily declined over the past 10 years — lead and carbon monoxide levels, for example, now meet international standards in most areas — emissions haven't fallen as much as predicted.
11 Oct 2013:
Agricultural Ammonia Emissions
Threatening U.S. National Parks, Study Finds
Ammonia emissions from agricultural fertilizers are threatening sensitive ecosystems in U.S. national parks, a study led by Harvard researchers
has found. Thirty-eight national parks are seeing nitrogen deposition levels at or above the threshold for ecological damage,
Great Smoky Mountains N.P.
the study says. In natural ecosystems, excess nitrogen can disrupt nutrient cycling in soil
, cause algal overgrowth, and make aquatic environments acidic. While some of that nitrogen comes in the form of nitrogen oxides (NOx) from power plants and vehicle exhaust, existing air quality regulations and new clean energy technologies are helping reduce NOx emissions. Ammonia emissions from agricultural operations, however, are expected to climb as demand for food and biofuels surges. Daniel Jacob, who led the study, said that because ammonia is volatile, only 10 percent of the nitrogen makes it into the food, with much of it escaping through the atmosphere and being deposited across the landscape. According to the report, published in Atmospheric Chemistry and Physics
, hardwood trees, such as those shown above, are most sensitive to excess nitrogen in eastern temperate forests, while in western national parks lichens appear to suffer first.