Environmental Engineering Reference
In-Depth Information
EPA), came to a similar conclusion. The USEPA has projected that ETS is
associated with approximately 3000 cases of lung cancer among nonsmokers
in the U.S. each year.
A variety of other cancers and exposure to ETS have been studied. These
include breast, cervical, and nasal cancers. Studies on both breast and cervical
cancer are inconclusive, but do have a degree of biological plausibility. Based
on several studies, there is an increased risk of nasal cancer in nonsmokers
exposed to ETS that varies from 1.7 to 3.0 times greater than in those not
exposed. This appears to be inconsistent with the apparent fact that there is
no increase in nasal cancer risk in smokers.
Epidemiological evidence suggests that exposure to ETS increases the
risk of cardiovascular disease in never-smokers. Studies that have controlled
for confounding risk factors, such as blood cholesterol, blood pressure, and
obesity, have reported an increased relative risk ranging from 1.59 to 2.01
associated with exposure to ETS. Both clinical and animal studies indicate
that exposure to ETS can increase blood COHb concentrations, increase
blood platelet aggregation, impair platelet function, lower high-density
lipoprotein cholesterol concentration, and increase fibrinogen concentra-
tion. The projected increase of deaths from ischemic heart disease among
never- and former smokers of 35,000 to 40,000 deaths per year is approxi-
mately an order of magnitude higher than that for lung cancer projections.
The lifetime risk of a male never-smoker living with a current or former
smoker dying from heart disease by the age of 74 has been estimated at
approximately 10%; the lifetime risk for a male never-smoker living with a
nonsmoker is estimated at 7%. Corresponding risks for female never-smok-
ers were 6% and 5%, respectively.
F. Biomass cooking
Given the high exposures to combustion-generated contaminants reported
above, significant adverse health effects can be expected. Indeed, the WHO
estimates that biomass cooking is responsible for approximately 2.2 to 2.5
million premature deaths a year.
Exposure to cooking smoke is a known risk factor for a number of
respiratory diseases. These include increased risk of acute respiratory infec-
tion, chronic obstructive lung disease, cor pulmonale, and lung cancer.
Acute respiratory illness includes infections by a number of bacteria and
viruses. In developing countries, respiratory infections in children often
proceed to pneumonia and death. Pneumonia is the chief cause of death in
children worldwide (approximately 4.3 million deaths per year). High inci-
dence rates occur in developing countries such as India. Based on epidemi-
ological studies, exposure to pollutants from biomass cooking increases the
risk (on the order of 2 to 3 times) of respiratory infections resulting in
pneumonia.
Chronic obstructive lung disease (COLD) is commonly associated with
tobacco smoking. Studies in countries such as New Guinea, India, and Nepal
