Air quality and human health - Air Pollution Modeling and Its Application - page 461

Vichit-Vadakan N, Vajanapoom N, Ostro B. The Public Health and Air Pollution in A sia
(PAPA) Project: Estimating the Mortality Effects of Particulate Matter in Bangkok, Thailand.
Environ Health Perspect. 2008;116:1179-82.
Wong CM, Ou CQ, Chan KP, Chau JK, Thach TQ, Yang L, et al. The Effects of Air Pollution on
Mortality in Socially Deprived Urban Areas in Hong Kong, China. Environ Health Perspect.
2008;116:1189-94.
Wong CM, Vichit-Vadakan N, Kan H, Qian Z. Public Health and Air Pollution in Asia (PA PA):
A Multicity Study of Short-Term Effects of Air Pollution on Mortality. Environ Health
Perspect. 2008;116:1195-202.
Lelieveld J, Crutzen PJ, Ramanathan V, Andreae MO, Brenninkmeijer CAM, Cam pos T, et al.
The Indian Ocean Experiment: Widespread air pollution from South and Southeast Asia.
Science. 2001 Feb 9;291(5506):1031-6.
4. Questions and Answers
Christian Reuter: Increase in life expectancy in US study related to decrease in
PM2.5 - could it be other factors?
Answer: Investigators tried to adjust for other known factors influencing life
expectancy, but only had indirect data on smoking. So further studies are
needed to corroborate this finding.
Katarzyna Juda-Rezler: EU health impact studies are based on US cohort, Pope
et al. studies. Is this reasonable?
Answer: Whereas there may be differences between Europe and US in terms of
pollution and population, both are highly developed regions with similar pollution
sources and lifestyles. Also, European cohort studies are starting to emerge that
by and large show similar findings.
M. Sofiev: Is the association between PM and health effects causal, or could it be
due to other pollutants and/or social factors?
Answer: In observational studies, there always remains a possibility that other
factors are responsible for the associations seen. However, especially the
associations between PM and health effects have been re-analyzed and
scrutinized likke no others, and there is now much support for causality also
from experimental studies.
Unknown: PM episodes are clearly associated with increases in mortality,
hospital admissions etc; but are these really extra cases or just cases advenced
in time by a few days or weeks?
Answer: This is called 'harvesting', and has received much attention in the
epidemiological literature. Generally, it appears that cases are not just advanced
by a few days or weeks, but that they are truly extra cases in the timeframe of
months or a few years.