[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Particulate Exposure on the Farm



Below is the summary of the most recent report on particulate matter's
effect on health from 

http://www.healtheffects.org/

 While this work was done in cities,  I wonder if people who live on farms
are exposed to similar fine particulates from field work, gravel roads,
engine exhaust, etc?  Think about the amount of the dust caused by a grain
or fertilizer truck going down the gravel road on a dry day?  Keeps the
soil pH up   :>)

Anybody have information on the paticulates to which people living in rural
area are exposed?  Seems to me that if these PM's affect older people, they
must affect younger people as well.  We all have lungs and then there is
that little inconvience that we all will grow old eventually unless we off
first.  

Mike Miller

HEI Summary below

S T A T E M E N T
Synopsis of Research Report 94, Part II
The National Morbidity, Mortality, and Air Pollution
Study: Morbidity and Mortality from Air Pollution
in the United States
This Statement, prepared by the Health Effects Institute, summarizes a
research project conducted by Dr Jonathan M Samet of Johns
Hopkins School of Public Health, Baltimore MD. The complete report, The
National Morbidity, Mortality, and Air Pollution Study,
Part II: Morbidity and Mortality from Air Pollution in the United States,
can be requested by mailing or faxing the enclosed order form
to HEI. With questions, please contact the HEI offices by phone, fax, or
e-mail (see reverse side). SAMET II 94

BACKGROUND
Epidemiologic time-series studies conducted in
a number of cities have identified, in general, an
association between daily changes in concentra-tion
of ambient particulate matter (PM) and daily
number of deaths (mortality). Increased hospital-ization
(a measure of morbidity) among the elderly
for specific causes has also been associated with
PM. These studies have raised concerns about pub-lic
health effects of particulate air pollution and have
contributed to regulatory decisions in the United
States. However, scientists have pointed out uncer-tainties
that raise questions about the interpreta-tion
of these studies.
One limitation to previous time-series studies of
PM and adverse health effects is that the evidence
for an association is derived from studies conducted
in single locations using diverse analytic methods.
Statistical procedures have been used to combine
the results of these single location studies in order
to produce a summary estimate of the health effects
of PM. Difficulties with this approach include the
process by which cities were selected to be studied,
the different analytic methods applied to each sin-gle
study, and the variety of methods used to mea-sure
or account for variables included in the analysis.
These individual studies were also not able to account
for the effects of gaseous air pollutants in a sys-tematic
manner.
APPROACH
HEI funded the National Morbidity, Mortality,
and Air Pollution Study (NMMAPS) to characterize
the effects of airborne particles less than 10 mm in
aerodynamic diameter (PM 10 ) alone and in combi-nation
with gaseous air pollutants in a consistent
way, in a large number of cities. The study was
designed to select multiple locations based on the
specific criteria of population size and availability
of PM 10 data from the US Environmental Protection
Agency’s Aerometric Information Retrieval System
(AIRS) database, and to apply the same statistical
procedures to all locations. Dr Jonathan Samet and
his colleagues at Johns Hopkins University con-ducted
a time-series study of mortality effects in
large US cities representing various levels of PM 10
and gaseous pollutants. In their analysis, the inves-tigators
first estimated risk in each city using the
same method and then combined these results sys-tematically
to draw more information than any sin-gle
city could provide. The 20 and 90 largest cities
were analyzed for effects of PM 10 and other pollu-tants
on mortality; the 90 largest cities were ana-lyzed
for possible modification of PM 10 effects among
cities by factors other than air pollutants. Dr Samet’s
coinvestigators at Harvard University also applied
a unified statistical method, although different from
the one used in the mortality analysis, to 14 cities
with daily PM 10 data to examine effects on hospi-talization
among those 65 years of age or older.
RESULTS AND IMPLICATIONS
NMMAPS has made a substantial contribution
in addressing major limitations of previous studies.
The mortality analysis used one analytic approach
to examine the PM 10 effect in many cities that cover
a wide geographic area and have varying levels of
different air pollutants. The results of both the 20
cities and 90 cities analyses are generally consistent
with an average approximate 0.5% increase in over-all
mortality for every 10 mg/m 3 increase in PM 10
measured the day before death. This effect was
slightly greater for deaths due to heart and lung disease
than for total deaths. Effects of PM 10 measured on the
day of death or 2 days before did not vary substantially
from one another for total or for heart and lung deaths.
The PM 10 effect on mortality also did not appear to be
affected by other pollutants in the model.
Although individual estimates for each of the 90 cities
varied, as expected, the strength of the analysis was in
its ability to combine data from nearby cities in a par-ticular
region to estimate a PM 10 effect. Combining the
data in this systematic way provided additional statisti-cal
power to the analysis that is not available in single-city
analyses. Some differences in PM 10 effect on mortality
were seen by region of the US: for the 90 cities, the largest
effect was evident in the Northeast. The investigators
did not identify any factor or factors that might explain
these differences. This analysis is an important first step,
and further evaluation of the reasons for these regional
differences will advance our understanding of the asso-ciation
between PM 10 and mortality. The heterogeneity
of effect across cities offers the potential to identify fac-tors
that could influence the effects of PM 10 on health
and thus provide valuable insights into the mechanisms
by which PM 10 causes adverse health effects.
The morbidity analysis also used a unified analytic
method to examine the association of PM 10 with hospi-talization
of those 65 years of age or older in 14 cities
with daily PM 10 measurements. The results were con-sistent
with an approximate 1% increase in admissions
for cardiovascular disease and about a 2% increase in
admissions for pneumonia and chronic obstructive pul-monary
disease for each 10 mg/m 3 increase in PM 10 . A
greater estimate of effect on hospitalizations at lower
concentrations (less than 50 mg/m 3 ) was found for the
three diagnoses considered, but the meaning of these
findings should await completion of concentration-response
analyses for mortality now under way using
data from 20 cities.
NMMAPS has made substantial contributions to our
understanding of the relationship between exposure to
PM 10 and health effects. Further analyses in these
databases of regional differences, the effects on mor-bidity
and mortality combined, and concentration-response
relationships will enhance our understanding.
Research Report 94, Part II
955 Massachusetts Avenue
Cambridge MA 02139 USA
+1-617-876-6700
+1-617-876-6709 fax
pubs@healtheffects.org
www.healtheffects.org Recycled Paper


To Unsubscribe:  Email majordomo@cals.ncsu.edu with the command
"unsubscribe sanet-mg".  If you receive the digest format, use the command
"unsubscribe sanet-mg-digest".
To Subscribe to Digest: Email majordomo@cals.ncsu.edu with the command
"subscribe sanet-mg-digest".

All messages to sanet-mg are archived at:
http://www.sare.org/san/htdocs/hypermail