We have assessed a range of high volume, low pressure (HVLP) cuffed tracheal tubes in a benchtop model, for leakage of fluid from above the cuff to the model trachea below, during various ventilatory modes. Rapid leakage occurred in the model during all modes of ventilation, unless tracheal pressure was greater than the height of fluid in the column above the cuff. This leakage occurred preferentially down longitudinal folds that occur in the HVLP cuff wall. This model suggests that, if a longitudinal fold within the cuff wall is patent, then the possibility exists of subglottic to tracheal leakage.
The combustion of
biomass and coal is the dominant source of household
air pollution (HAP) in China, and contributes significantly to the
total burden of disease in the Chinese population. To characterize
HAP exposure related to solid fuel use and ventilation patterns, an
exposure assessment study of 163 nonsmoking female heads of households
enrolled from 30 villages was conducted in Xuanwei and Fuyuan, two
neighboring rural counties with high incidence of lung cancer due
to the burning of smoky coal (a bituminous coal, which in health evaluations
is usually compared to smokeless coal—an anthracite coal available
in some parts of the area). Personal and indoor 24-h PM2.5 samples were collected over two consecutive days in each household,
with approximately one-third of measurements retaken in a second season.
The overall geometric means (GM) of personal PM2.5 concentrations
in Xuanwei and Fuyuan were 166 [Geometric Standard Deviation (GSD):2.0]
and 146 (GSD:1.9) μg/m3, respectively, which were
similar to the indoor PM2.5 air concentrations [GM(GSD):162
(2.1) and 136 (2.0) μg/m3, respectively]. Personal
PM2.5 was moderately highly correlated with indoor PM2.5 (Spearman r = 0.70, p < 0.0001). Burning wood or plant materials (tobacco stems, corncobs
etc.) resulted in the highest personal PM2.5 concentrations
(GM:289 and 225 μg/m3, respectively), followed by
smoky coal, and smokeless coal (GM:148 and 115 μg/m3, respectively). PM2.5 levels of vented stoves were 34–80%
lower than unvented stoves and firepits across fuel types. Mixed effect
models indicated that fuel type, ventilation, number of windows, season,
and burning time per stove were the main factors related to personal
PM2.5 exposure. Lower PM2.5 among vented stoves
compared with unvented stoves and firepits is of interest as it parallels
the observation of reduced risks of malignant and nonmalignant lung
diseases in the region.
Background:
There is growing evidence that exposure to ultrafine particles (UFP; particles smaller than
) may play an underexplored role in the etiology of several illnesses, including cardiovascular disease (CVD).
Objectives:
We aimed o investigate the relationship between long-term exposure to ambient UFP and incident cardiovascular and cerebrovascular disease (CVA). As a secondary objective, we sought to compare effect estimates for UFP with those derived for other air pollutants, including estimates from two-pollutant models.
Methods:
Using a prospective cohort of 33,831 Dutch residents, we studied the association between long-term exposure to UFP (predicted via land use regression) and incident disease using Cox proportional hazard models. Hazard ratios (HR) for UFP were compared to HRs for more routinely monitored air pollutants, including particulate matter with aerodynamic diameter
(
), PM with aerodynamic diameter
(
), and
.
Results:
Long-term UFP exposure was associated with an increased risk for all incident CVD [
per
; 95% confidence interval (CI): 1.03, 1.34], myocardial infarction (MI) (
; 95% CI: 1.00, 1.79), and heart failure (
; 95% CI: 1.17, 2.66). Positive associations were also estimated for
(
; 95% CI: 1.01, 1.48 per
) and coarse PM (
; HR for all
; 95% CI: 1.01, 1.45 per
). CVD was not positively associated with
(HR for all
; 95% CI: 0.75, 1.28 per
). HRs for UFP and CVAs were positive, but not significant. In two-pollutant models (
and
), positive associations tended to remain for UFP, while HRs for
and
generally attenuated towards the null.
Conclusions:
These findings strengthen the evidence that UFP exposure plays an important role in cardiovascular health and that risks of ambient air pollution may have been underestimated based on conventional air pollution metrics.
https://doi.org/10.1289/EHP3047
Exposure
to polycyclic aromatic hydrocarbons (PAHs) from burning
“smoky” (bituminous) coal has been implicated as a cause
of the high lung cancer incidence in the counties of Xuanwei and Fuyuan,
China. Little is known about variations in PAH exposure from throughout
the region nor how fuel source and stove design affects exposure.
Indoor and personal PAH exposure resulting from solid fuel combustion
in Xuanwei and Fuyuan was investigated using repeated 24 h particle
bound and gas-phase PAH measurements, which were collected from 163
female residents of Xuanwei and Fuyuan. 549 particle bound (283 indoor
and 266 personal) and 193 gas phase (all personal) PAH measurements
were collected. Mixed effect models indicated that PAH exposure was
up to 6 times higher when burning smoky coal than smokeless coal and
varied by up to a factor of 3 between different smoky coal geographic
sources. PAH measurements from unventilated firepits were up to 5
times that of ventilated stoves. Exposure also varied between different
room sizes and season of measurement. These findings indicate that
PAH exposure is modulated by a variety of factors, including fuel
type, coal source, and stove design. These findings may provide valuable
insight into potential causes of lung cancer in the area.
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