Air Pollution: There's More To It Than Just Greenhouse Gases

Plus Native Plants for Your Front Yard, the Mountain Valley Pipeline, Big Banks and Corporations Called Out, Too Many Cows, and Good News for Migratory Birds

We’re Spewing More Than CO2 into the Air

The increase in atmospheric CO2 levels has dominated headlines for so long that we often forget that we are spewing a lot of other pollutants into the atmosphere as well. We also tend to think of air pollution as a modern problem, a scourge that accompanied the steam engine and the rest of the industrial revolution, but it’s been around for a long, long time. Romans who lived during the time of the empire complained about the smoke that plagued the imperial city. And for hundreds of years, burning coal has left dense smoke in many cities throughout the world.1

The first mentions of air pollution in The New York Times come from two letters to the editor,2 3 in late May and early June of 1924. Both authors bemoaned the impurities in the air from power plants, tug boats, and steamers, and their threats to clear skies.

The rest of the 1920s saw a growing concern about the ash and soot billowing from factory smokestacks. Almost 100 years later, New York is still plagued by air pollution, as are thousands of other cities all over the world.

The Centers for Disease Control and Prevention lists a number of substances that pollute our air, including lead, benzene, asbestos, and things known as synthetic vitreous fibers—substances made from aluminum or calcium silicates that do not occur in nature and are used for insulation and strengthening other building materials.

Air pollution sickens and kills people. Making the connection between high rates of air pollution and higher rates of lung cancer, as well as other cancers, the World Health Organization (WHO) classified air pollution as a carcinogen in 2013. WHO estimates that ailments caused by air pollution were responsible for the deaths of 4.2 million people worldwide annually over the last several years, with most of those deaths occurring in Africa and Asia.4


While China decommissioned coal-fired power stations in 2020, newly constructed stations added that year resulted in a net gain of 29.8 gigawatts (GW) of power over 2019. Power stations producing a further 36.9 GW are planned for construction. In all, China is on the path to having 247 GW of coal-fired power in the near future.

Of the fossil fuels, coal can be particularly polluting. Sulfur dioxide (SO2), nitrogen oxides (NOx), and particulate matter, or soot are among the pollutants produced by burning coal. All of these pollutants have been linked to asthma and bronchitis. Soot has also been associated with cardiovascular disease and heart attacks. Nitrogen oxides can make folks susceptible to pneumonia and flu. Recent research has even linked air pollution to reduced cognitive ability among older men.

Sulfur dioxide forms acidic particulates when it reacts with other molecules in the atmosphere, resulting in acid rain, which can damage buildings and crops, and acidify lakes and streams. The burning of coal also releases mercury and lead, both of which are neurotoxins.

China’s ultra-low emission standards

Although China has been eager to build new coal-fired power plants, they also established, in 2014, ultra-low emissions (ULE) standards for these plants. The ULE standards are among the most stringent in the world, requiring reductions of SO2, NOx, and particulate matter down to the levels of power plants that use natural gas.

By monitoring China’s power generation system from 2014, when the standards were first implemented, until 2017, Chinese scientists were able to determine that the adoption of the ULEs removed 65 percent of SO2, 60 percent of NOx, and 72 percent of particulate matter. The team of scientists performed hour-by-hour monitoring of between 96 and 98 percent of China’s power generation capacity.

The authors of the study describe the technologies used to make the pollution reductions and published their findings in the journal Nature in October 2019.

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And of course, there is more to the picture

China’s ULEs apply exclusively to coal-fired power stations. More recently, another team of scientists looked at how much good the ULEs actually achieved.

Left out of the ULEs’ jurisdiction are boilers, cement factories, and iron and steel factories. The scientists looked at overall pollution reductions and limited the scope of their study to the Yangtze River Delta. This region was selected because it is one of the most densely populated regions of China and one of the places where ULEs were first implemented.

Overall, the scientists found that implementation of the ULEs reduced SO2, NOx and particulate matter by less than seven percent.

If the ULEs were to be extended to other industrial sources, the scientists estimate that the reductions would be 33 to 64 percent for SO2, 16 to 23 percent for NOx, and 6 to 22 percent for particulate matter. The range in reductions are due to the weather, with the lower reductions occurring during warmer months of the year.

The scientists further estimate that 305 deaths and 8744 years of life loss were avoided because of the implementation of the ULEs in the Yangtze River Delta. If the ULEs were fully implemented for all production, including the cement factories, boilers, and iron and steel facilities, the scientists say that 10,651 deaths and 316,562 years of life loss could be avoided.

The research team was affiliated with Chinese universities, as well as Harvard and Cambridge Universities. The team published their findings in the journal Atmospheric Chemistry and Physics on April 27, 2021.

And then, there’s always Los Angeles

I’m a big fan of Raymond Chandler. I love his spare style and ability to create penetrating scenes. Because he set may of his classic crime novels in Los Angeles, I have a certain love for the city. Yet despite the City of Angels being a little more than 100 miles from where I live, I rarely go there.

Los Angeles can seem like a big expanse of freeways with Hollywood and a lot of Starbucks thrown in. Everything is far away and there is always traffic. And it is the one city in the U.S. that is synonymous with smog. Those are all things I hate.

Chandler’s hardboiled detective, Philip Marlowe, drives around 1930s Los Angeles and is surrounded by mountains and expansive acres of citrus groves. Yet even by that time, smog was obscuring the views and stinging the eyes of LA residents. In 1943, Los Angeles was hit by its first severe smog attack. As we have gotten through a year of masking up to fight the coronavirus, consider this 1954 photo of the Highland Park Optimist Club. The Los Angeles smog was so bad that the club held a banquet while wearing gas masks.

It took a while for Angelinos to make the connection between their cars and the smog that enveloped them and their city. Los Angeles County has 515 miles of freeway and expressway, and that doesn’t include the thousands of miles of residential and city streets. The California Department of Transportation estimates that 221.8 million vehicle miles are driven every day in Los Angeles.

LA is also warm throughout the year, which exacerbates the production of smog. No matter which way the wind blows, the air in the LA basin tends to stay put, so the smog builds up.

The Clean Air Act, as well as the use of catalytic converters, has done much to remedy Los Angeles’ smog problem. But it still exists. All those cars driving all those miles still means there are lots of tailpipes pumping out lots of pollutants into the air, and that means that there is still smog in Los Angeles.

Los Angeles smog drifts into the San Gabriel Mountains

Though the smog in Los Angeles tends to sit in the LA Basin, it does drift out. Scientists recently assessed how much the Los Angeles smog affects the surrounding San Gabriel Mountains.

Home to pine forests and peaks that retain snow throughout the year, the San Gabriel Mountains are the polar opposite of Los Angeles: crisp, wild, and filled with nature.

The mountains are also right next to LA. Using LiDAR and other measuring techniques, the scientists, most of whom are affiliated with the Jet Propulsion Laboratory in Pasadena, California, measured ground-level ozone, another component of smog, in the San Gabriel Mountains. They found a large number of days when the ozone levels in the mountains exceeded the National Ambient Air Quality Standards from late spring through early fall, with the greatest number of “bad air days” occurring in June. In other words, you could be tramping among the pines with your boots and backpack in the San Gabriels, and as far as your lungs are concerned, you’re still in the middle of Los Angeles.

The scientists identified several pathways for the LA smog to reach the mountains, but it just seems to make sense that if you’re that close to Los Angeles, you’re bound to get some smog.

The results of the scientists’ work were published in Atmospheric Chemistry and Physics on April 23, 2021.

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New Voices

This month’s op-ed is from Dave Flietner from southern California

Show off your environmental bona fides with your front yard

The COVID-19 pandemic has shown us how relentless and remorseless nature can be. The virus continues to spread and kill, whether we acknowledge it or not. Perhaps this demonstration of the indifference of nature to our desires will steel us for the long slog ahead as we fight climate change. In COVID terms, it’s March 2020 and we’ve finally realized this is serious and we’re in trouble.

Thirty years from now, even if we have achieved net-zero carbon emissions, the climate will still be hotter, wilder, and deadlier than it is today, with conditions unlikely to return to the “old normal” before the end of the century. We will look back at the 2020s as “the good old days,” when hurricanes and wildfires still made the front page.  

Of course, we need to fight climate change through participation in democracy in all its forms—voting, letter writing, demonstrating, and political activism. Beyond that, we need a realignment in the zeitgeist so that everyone is committed to reversing climate change. An anti-warming, pro-nature attitude needs to become the social norm: it should be as socially unacceptable to squander carbon dioxide as it is to litter. 

Given the decline of participation in civic institutions, from churches to bowling leagues, and increased social atomization, our consumer choices have become the main way we can project a pro-nature ethos to our fellow citizens. Many personal choices, like a low-meat diet and efficient appliances, are critical but largely invisible. Our choice of what type of car we drive (if we choose to drive one at all) makes a statement to others driving on the freeway, but this anonymous, transient presentation to total strangers isn’t likely to impact their sense of what is acceptable behavior.  

I suggest that the biggest statement we can make to our neighbors, and by extension to society as a whole, is at home. Installing solar panels is an obvious and economically wise first step. But I’d like to suggest a venue where we can make a more personal expression of our values: the front yard. This is the face we project to society and contributes to the personality of the neighborhood. The landscaping choices we make should reflect our environmental values.

At the most basic level, substituting trees and shrubs for a lawn means that carbon is stored in the woody stems rather than lawn clippings that will end up either as compost, where they will break down to CO2, or in a landfill, where they will break down anaerobically, releasing methane, another greenhouse gas.  

More importantly, carbon is sequestered in the much larger root systems of woody plants, which mostly end up as soil organic matter, out of the carbon cycle potentially for millennia. If these woody plants are native to the region, they’re likely to provide food and shelter to native insects, birds, and animals, which may not impact carbon storage but is a nice reminder that we’re part of the larger natural world.

A nine-year study in Santa Monica, California, found that a native plant landscape produced 56% less green waste and used 83% less water (and needed one-third less labor). Yard waste from that landscape will release 1,400 pounds of CO2 annually if it is mulched. But four times that amount of CO2 is generated to fertilize, weed, mow, and water a similar-sized plot of grass, according to a UC Irvine study. In southern California, where I live, a big part of that CO2 results from the energy needed to move water hundreds of miles from the Colorado or Sacramento Rivers each year. The water savings with native plants also saves about 1,000 pounds of CO2 each year alone, based on the average U.S. energy mix. 

If you see a junk car up on cement blocks in an unkempt weed lot, you’re likely to make a negative inference about the occupant’s values. In a society fighting to restore a connection with the natural world, a lush green lawn maintained by inputs of chemical fertilizers, pesticides, and belching lawn mowers should likewise signal that an antisocial narcissist lives there.  

You can capture a little bit of carbon, avoid using a lot more, and encourage your neighbors to do the same by making a statement in your own front yard.

Dave Flietner, who holds an MS in Botany from the University of Florida, is a botanist with 20 years of experience as an environmental consultant in southern California. He is the proprietor of Design With Natives landscape design.

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Other News

Fracked gas line once again rejected by North Carolina

The North Carolina Department of Environmental Quality announced late last month that it was, for the second time, rejecting the extension of the Mountain Valley Pipeline into North Carolina. (Appalachian Voices)

The pipeline, which has partially been constructed, starts in north-central West Virginia and goes south into Virginia. Like the Keystone Pipeline, there has been opposition to the pipeline from its inception and continuing today.

Big banks and corporations are no friends to rainforests or human rights

The Rainforest Action Network (RAN) released a scorecard ranking the complicity and abetment of major corporations in human rights abuses and rainforest destruction. RAN singled out the banks of BNI, CIMB, ICBC, JPMorgan Chase, and MUFG, as well as the corporations of Colgate-Palmolive, Ferrero, Kao, Mondeléz, Nissin Foods, and Procter & Gamble as being the worst offenders, all of which received the grade of “F”. (Rainforest Action Network)

The Biden Administration moves to reinstate protections for migratory birds

The Migratory Bird Treaty Act has been a bedrock of American conservation since its passage in 1918. The Biden administration is poised to undo limitations the Trump administration imposed on the ability of the act to protect birds. (Audubon Society)

The Bureau of Land Management allows too many cows on national monument lands

The Center for Biological Diversity has found evidence of too much cattle grazing at the Agua Fria National Monument, a beautiful land of mesas and desert scrub about 40 miles north of Phoenix.

Some cattle grazing is allowed in the 71,000-acre preserve, but with too many cattle, the streams and riparian areas that are habitat for the threatened yellow-billed cuckoo and endangered Gila chub are being overly trod. (Center for Biological Diversity)



"Air pollution." Environmental Encyclopedia, edited by Deirdre S. Blanchfield, Gale, 2011. Gale In Context: Science, Accessed 4 May 2021.


Gerdes, Theodore R. N. "Engineer Sees Menace to New York from Fuel Oil and Soft Coal." New York Times (1923-Current file), May 31, 1924, pp. 14. ProQuest,


Jahn, C. F. "Necessity of Drastic Action to End Air Pollution is Urged." New York Times (1923-Current file), Jun 07, 1924, pp. 12. ProQuest,


"Air pollution." Environmental Encyclopedia, edited by Deirdre S. Blanchfield, Gale, 2011. Gale In Context: Science, Accessed 4 May 2021.