Cleaner air, longer lives

News specifically pertaining to Air Pollution-Related Health Issues

Moderator: turning_blue

Cleaner air, longer lives

Postby Wilberforce » Thu Dec 28, 2017 9:01 am

Cleaner air, longer lives
Clean Air Act is likely responsible for dramatic decline in atmospheric organic aerosol

Date: December 26, 2017
Source: Massachusetts Institute of Technology
Summary: A new study shows that the Clean Air Act is likely responsible for dramatic decline in atmospheric organic aerosol in the U.S.

The air we breathe contains particulate matter from a range of natural and human-related sources. Particulate matter is responsible for thousands of premature deaths in the United States each year, but legislation from the U.S. Environmental Protection Agency (EPA) is credited with significantly decreasing this number, as well as the amount of particulate matter in the atmosphere. However, the EPA may not be getting the full credit they deserve: new research from MIT's Department of Civil and Environmental Engineering (CEE) proposes that the EPA's legislation may have saved even more lives than initially reported.

"In the United States, the number of premature deaths associated with exposure to outdoor particulate matter exceeds the number of car accident fatalities every year. This highlights the vital role that the EPA plays in reducing the exposure of people living in the United States to harmful pollutants," says Colette Heald, associate professor of CEE and Earth, Atmospheric and Planetary Sciences.

The EPA's 1970 Clean Air Act and additional amendments enacted in 1990 address the health effects of particulate matter, specifically by regulating emissions of air pollutants and promoting research into cleaner alternatives. In 2011 the EPA announced that the legislation was responsible for a considerable decrease in particulate matter in the atmosphere, estimating over 100,000 lives saved every year from 2000 to 2010. However, the report did not consider organic aerosol, a major component of atmospheric particulate matter, to be a large contributor to the decline in particulate matter during this period. Organic aerosol is emitted directly from fossil fuel combustion (e.g. vehicles), residential burning, and wildfires but is also chemically produced in the atmosphere from the oxidation of both natural and anthropogenically-emitted hydrocarbons.

The CEE research team, including Heald; Jesse Kroll, an associate professor of CEE and of chemical engineering; David Ridley, a research scientist in CEE; and Kelsey Ridley SM '15, looked at surface measurements of organic aerosol from across the United States from 1990 to 2012, creating a comprehensive picture of organic aerosol in the United States.

"Widespread monitoring of air pollutant concentrations across the United States enables us to verify changes in air quality over time in response to regulations. Previous work has focused on the decline in particulate matter associated with efforts to reduce acid rain in the United States. But to date, no one had really explored the long term trend in organic aerosol," Heald says.

The MIT researchers found a more dramatic decline in organic aerosol across the U.S. than previously reported, which may account for more lives saved than the EPA anticipated. Their work showed that these changes are likely due to anthropogenic, or human, behaviors. The researchers' findings were published in a paper, "Causes and Consequences of decreasing atmospheric organic aerosol in the U.S." in the Proceedings of the National Academy of Sciences the week of December 25.

"The EPA report showed a very large impact from the decline in particulate matter, but we were surprised to see a very little change in the organic aerosol concentration in their estimates," explains David Ridley. "The observations suggest that the decrease in organic aerosol had been six times larger than estimated between 2000 and 2010 in the EPA report."

Using data from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network, the researchers found that organic aerosol decreased across the entire country in the winter and summer seasons. This decline in organic aerosol is surprising, especially when considering the increase in wildfires. But the researchers found that despite the wildfires, organic aerosols continue to decline.

The researchers also used information from the NASA Modern-Era Retrospective Analysis for Research and Applications to analyze the impact of other natural influences on organic aerosol, such as precipitation and temperature, and found that the decline would be occurring despite cloud cover, rain, and temperature changes.

The absence of a clear natural cause for the decline in organic aerosol suggests the decline was the result of anthropogenic causes. Further, the decline in organic aerosol was similar to the decrease in other measured atmospheric pollutants, such as nitrogen dioxide and carbon monoxide, which are likewise thought to be due to EPA regulations. Also, similarities in trends across both urban and rural areas suggest that the declines may also be the result of behavioral changes stemming from EPA regulations.

By leveraging the emissions data of organic aerosol and its precursors from both natural and anthropogenic sources, the researchers simulated organic aerosol concentrations from 1990 to 2012 in a model. The researchers found that more than half of the decline in organic aerosol is accounted for by changes in human emissions behaviors, including vehicle emissions and residential and commercial fuel burning.

"We see that the model captures much of the observed trend of organic aerosol across the U.S., and we can explain a lot of that purely through changes in anthropogenic emissions. The changes in organic aerosol emissions are likely to be indirectly driven by controls by the EPA on different species, like black carbon from fuel burning and nitrogen dioxide from vehicles," says Ridley. "This wasn't really something that the EPA was anticipating, so it's an added benefit of the Clean Air Act."

In considering mortality rates and the impact of organic aerosol over time, the researchers used a previously established method that relates exposure to particulate matter to increased risk of mortality through different diseases like cardiovascular disease or respiratory disease. The researchers could thus figure out the change in mortality rate based on the change in particulate matter. Since the researchers knew how much organic aerosol is in the particulate matter samples, they were able to determine how much changes in organic aerosol levels decreased mortality.

"There are costs and benefits to implementing regulations such as those in the Clean Air Act, but it seems that we are reaping even greater benefits from the reduced mortality associated with particulate matter because of the change in organic aerosol," Ridley says. "There are health benefits to reducing organic aerosol further, especially in urban locations. As we do, natural sources will contribute a larger fraction, so we need to understand how they will vary into the future too."

This research was funded, in part, by the National Science Foundation, the National Aeronautics and Space Administration, and the National Oceanic and Atmospheric Administration.

Story Source:

Materials provided by Massachusetts Institute of Technology. Original written by Carolyn Schmitt. Note: Content may be edited for style and length.

Journal Reference:

D. A. Ridley, C. L. Heald, K. J. Ridley, J. H. Kroll. Causes and consequences of decreasing atmospheric organic aerosol in the United States. Proceedings of the National Academy of Sciences, 2017; 201700387 DOI: 10.1073/pnas.1700387115

source ... 105042.htm

Thousands Were Saved Between 1990 and 2012 as Air Pollution Declined
Written By Chelsea Gohd
@chelsea_gohd Website
Published: December 26, 2017

In Brief
It seems like currently, all environmental news is terrifying and life-threatening. But one new study shows how, between 1990 and 2012, particulate matter and organic aerosols significantly declined in the United States, saving thousands of lives.

Clearing the Air

When it comes to climate change, it can be difficult to remain optimistic about the fate of the planet. We are already feeling impacts such as increased forest fires and sea level rise, and as global temperatures continue to rise we can only expect more. People and most governments around the world are accepting that battling our changing climate is a matter of survival.

But, while countries like the United States seem to be dismissing its threat, we all still face the same brutal reality of our warming planet. However, amid a series of worrying projections, one recent study stands out as a silver lining. It finds that the amount of gases derived by the combustion of organic matter, such as fossil fuels and forest fires, decreased in the United States from 1990-2012. The dip in what scientists call “organic aerosols” averted 180,000 deaths that would typically be associated with their exposure.

Globally, exposure to these gases is estimated to cause over 4 million deaths every year. The researchers believe that by tracing back the causes of the recent emission decline, we could inform policies that would save many of those lives.
Long lasting improvements

David Andrew Ridley and his colleagues isolated the trend by analyzing the concentration in the air of organic aerosols and black carbon, the sooty dark fumes created from the incomplete combustion of fossil fuels and biomass.

Soot can come, for example, from old diesel cars, wood burning or cook stoves and is particularly dangerous for the lungs and heart.

The research team found that between 1990-2012, organic aerosols and black carbon decreased by 40% and 55%, respectively. Overall, this is a 30 percent decrease in particle pollution in the U.S.

These findings are particularly impressive, considering that the increase in the number of wildfires should have contributed to this type of pollution. But other sources of aerosols were so drastically reduced that the negative impacts of forests burning was eventually offset.

The study’s authors believe that the encouraging trend could be a byproduct of the Clean Air Act, a federal law introduced in 1970 that regulated the emissions of hazardous pollutants.

As environmental protection is rolled back in the U.S. and fossil fuels are promoted as a means to create jobs for the poor, the study comes as a reminder that good environmental governance is not just a matter of politics: it can deliver concrete, long lasting benefits.

source ... -declined/
• The Surgeon General has determined that there is no safe level of exposure to ambient smoke!

• If you smell even a subtle odor of smoke, you are being exposed to poisonous and carcinogenic chemical compounds!

• Even a brief exposure to smoke raises blood pressure, (no matter what your state of health) and can cause blood clotting, stroke, or heart attack in vulnerable people. Even children experience elevated blood pressure when exposed to smoke!

• Since smoke drastically weakens the lungs' immune system, avoiding smoke is one of the best ways to prevent colds, flu, bronchitis, or risk of an even more serious respiratory illness, such as pneumonia or tuberculosis! Does your child have the flu? Chances are they have been exposed to ambient smoke!
User avatar
Posts: 5965
Joined: Wed Jul 25, 2007 11:36 pm
Location: USA

Return to Health News

Who is online

Users browsing this forum: No registered users and 2 guests