Environmental Engineering Reference
In-Depth Information
to have more than a twofold higher risk of lower respiratory symptoms and
illness (fever, chest pain, productive cough, wheeze, chest cold, bronchitis,
pneumonia, or asthma) than children at lower exposures in non-kerosene
stove-using homes. Increased risks of upper respiratory symptoms (sore
throat, nasal congestion, dry cough, croup, or head cold) were also reported.
D. Carcinogens and cancer
By-products of combustion other than those associated with tobacco smoke
may contain a variety of carcinogenic substances. Most notably these include
PAHs. Many PAHs are potent carcinogens, particularly benzo-
α
-pyrene.
Benzo-
-pyrene exposure in ambient (outdoor) air has been implicated as a
risk factor for lung cancer in European epidemiological studies. Since PAH
concentrations are often higher in wood smoke, exposures associated with
wood-burning appliances may pose a cancer risk.
Few studies have attempted to evaluate cancer risks associated with
exposure to nontobacco-related combustion by-products. Interestingly, a U.S.
study designed to evaluate potential risk factors for childhood leukemia (see
Chapter 4) observed a significant increase in childhood leukemia in house-
holds where incense was burned
α
once a week during pregnancy, with a
significant increase in this risk when incense was burned regularly by the
mother. These risks were observed even after data were adjusted for con-
founding variables. Burning incense has been reported to produce benzo-
≥
α
-
pyrene, several other PAHs, and the nasal carcinogen, sinapaldehyde.
E. Environmental tobacco smoke
Numerous studies have been conducted to evaluate the potential health
effects of exposure to ETS on nonsmokers. These have included surveys of
nonsmoker complaints of irritant symptoms; controlled laboratory chamber
studies of human exposures, which have focused on irritation symptoms;
cross-sectional epidemiological studies attempting to evaluate risk factors
for sick building (SBS)-type symptoms; epidemiological evaluations of res-
piratory health risks including pulmonary function changes, asthma, and
lung cancer; and epidemiological studies focusing on a variety of nonrespi-
ratory health risks.
Several survey studies have attempted to evaluate irritant effects asso-
and nonallergic nonsmokers reported relatively high prevalence rates for
symptoms such as eye and nasal irritation, headache, and cough. Individuals
with allergy reported a significantly higher prevalence of respiratory symp-
toms (nasal symptoms, cough, wheezing).
Studies of human exposures to ETS, for the most part, have demon-
strated dose-response relationships between tobacco smoke complaints and
symptoms of nasal and eye irritation. Annoyance with air quality was
observed to increase with higher ETS levels. Factors apparently responsible
for irritation and annoyance included acrolein, HCHO, and RSP.
