In the past few decades, air quality in the United States
has been slowly increasing thanks to new acts and standards that have been
adopted. North Carolina took an additional step in improving air quality by
joining the Southern Appalachian Mountains Initiative, which helped lead to the
Clean Smokestacks Act that reduces coal-plant emissions. As the air quality
slowly improves in this area, it provides scientists with the unique opportunity
to see how changes in air quality affects mortality rates of diseases related
to respiratory problems.
In the study published by The International Journal of COPD,
scientists looked at how the concentrations of ozone, CO, NOx, SO2,
PM2.5, and PM10 were related to changes in mortality
rates of emphysema, asthma, and pneumonia. The air quality data was collected
from EPA public data files for 1993-2010 and the mortality rates for emphysema,
asthma, and pneumonia for North Carolina were collected from the Vital
Statistics National Center for Health Statistics Multiple Cause of Death dataset
from 1983-2010. Adjustments were made in the study for smoking prevalence and
seasonal fluctuations in respiratory deaths. The relationships were all studied
using a log-linear model. The statistical Bonferroni correction was used when
looking at multiple comparisons.
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Air quality measurements of North Carolina from 1993 to 2010
using arbitrary units to show the general decreasing trend in air pollutants.
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The study found that the air quality in North Carolina is
slowly increasing, mainly due to decreases in CO, NO2, and PM10
levels. They also found that since 1983 the mortality rates of the three
studied diseases also have decreased, although dramatic decreases started at
different times for each of the diseases. Pneumonia death rates have been
decreasing more dramatically since 1990, while asthma decreased more since 1995
and emphysema since 1998. These decreases in mortality rates for each disease
were related to changes in different atmospheric pollution levels. The decrease
in the mortality rate of emphysema was related to decreases in ozone, SO2,
NO2, CO, and PM2.5, but only SO2 and CO were
still significant after the Bonferroni correction. NO2, SO2,
CO, and PM10 decreases were shown to correlate with decreases in
asthma mortality, with only NO2 not significant under the Bonferroni
correction. Decrease in pneumonia deaths was only found to be correlated with
decreasing SO2 levels.
The article in the New York Times that discussed this study
was very short. Although the article did mention that the study corrected for
smoking and seasonal variations, it also got some points wrong. The article
says that SO2, PM, NO2, and CO “decreased markedly from
month to month” while graphs in the study show that there were some times that
each of these compounds increased in concentration. It mentions that both
emphysema and pneumonia death rate decreases were related to SO2 and
CO, which is correct but it didn’t mention that asthma mortality decreased with
PM10 also. Even though there was little mention of the methods of
this study, a detailed description would have seemed out of place in this short
of an article. I also thought that ending the article with a quote from lead
author was a great way of showing that air quality studies on health effects is
still being investigated.
Overall, I would have to give this article a 7/10. It gave
some wrong information and mentioned almost no methods, but it did get the
general idea of the study across in a very small amount of space.
New York Times article: http://well.blogs.nytimes.com/2014/06/23/cleaner-air-linked-to-fewer-deaths/?_r=0
International Journal of COPD (through MLibrary): http://dl2af5jf3e.scholar.serialssolutions.com.proxy.lib.umich.edu/?sid=google&auinit=J&aulast=Kravchenko&atitle=Long-term+dynamics+of+death+rates+of+emphysema,+asthma,+and+pneumonia+and+improving+air+quality&id=doi:10.2147/COPD.S59995&title=International+journal+of+chronic+obstructive+pulmonary+disease&volume=9&date=2014&spage=613&issn=1176-9106
I liked how the study focused on one state (North Carolina) and focused on specific counties in its sensitivity analysis. While that helped limit confounding factors, both the article and International Journal of COPD publication did a good job of addressing what the study did not control for.
ReplyDeleteI also feel that if the article were to get all (or even most of) the details correct, its length would probably be significantly longer. This might be a reason the article made some generalizations that were at least partially incorrect?
I definitely agree that generalizations, which might lead to incorrectness, have to be made sometimes but just to be really picky they could have said "an overall decrease" instead of "decreased markedly" when mentioning the improving air quality without having to add much extra space.
DeleteThe article mentions that there was no control for socioeconomic status or access to medical care. I would be interested to see the number of diagnoses of each of these diseases, and a comparison to their mortalities dependent on access to better, more efficient health care.
ReplyDeleteIt would also be interesting to see the difference in prevalence from state to state, especially those with an emphasized basis on industry.
It's an interesting study and from my perspective, the article did a good job. I'm also curious about the difference in prevalence from state to state, since this study is based on data from North Dakota.
ReplyDeleteWe usually witness increased disease rate as a result of worse pollution. It's interesting and uplifting to see some evidence for the other way around, that improvement in air quality indeed helps keep people away from illness.
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