Problems in Deciding the Effect of the Airborne Particulate Load in Hospitals on Patient Health

Abstract

Probably the most important factor to be considered when considering the health effects resulting from a level of pollutant concentration is that some fraction of the population will be affected more than the rest. This fraction is usually held to comprise the very young, the elderly and those compromised through various medical conditions. The patient population in a hospital is largely drawn from just this group of people. In most cases they spend 100% of their time in an indoor environment. Although many studies have been published associating particulates in the air with excess mortality, it is difficult to quantitate the effect and probably impossible to set an experimentally based guideline for particulates in indoor air that would have any validity for a hospital environment. The main reason for the lack of such evidence is that the epidemiological methods which have revealed associations between current outdoor concentrations of particles and health outcomes cannot be applied to indoor exposures. Those epidemiological studies using time-series techniques have shown statistically significant associations between outdoor particulate levels and admissions to hospital for treatment of respiratory and cardiovascular diseases and daily deaths from these causes. However, the effect of continued exposure in hospital on people compromised through age or health status will be difficult to ascertain. It may be that the best we will be able to do in the absence of acquiring hard data will be to apply the precautionary principle and lower particle levels - just in case it helps.