Abstract There have been few recent studies demonstrating a definitive association between the transmission of airborne infections and the ventilation of buildings. The severe acute respir...

Review the epidemiology and clinical consequences of arsenic exposure. Explain the relationships found in this case-control study among cumulative arsenic exposure, primary and secondary arsenic methylation, gender, and skin cancer. Understand how widely—if at all—the study findings may be generalized to populations other than the Taiwanese. Arsenic is a known carcinogen, but data are especially lacking on the health effects of low-level exposure, and on the health significance of methylation ability. We conducted a case-control study (76 cases and 224 controls from 1996 to 1999) in southwestern Taiwan to explore the association among primary and secondary arsenic methylation index (PMI and SMI, respectively), cumulative arsenic exposure (CAE), and the risk of skin cancer. As compared with the controls, the skin cancer group reported more sun exposure (P = 0.02) and had a lower BMI (P = 0.03), as well as lower education level (P = 0.01). Skin cancer patients and controls were similar with regard to age, gender, smoking and alcohol consumption. Given a low SMI (≤5), CAE > 15 mg/L-year was associated with an increased risk of skin cancer (OR, 7.48; 95% CI, 1.65–33.99) compared to a CAE ≤2 mg/L-year. Given the same level of PMI, SMI, and CAE, men had a higher risk of skin cancer (OR, 4.04; 95% CI, 1.46–11.22) when compared to women. Subjects with low SMI and high CAE have a substantially increased risk of skin cancer. Males in all strata of arsenic exposure and methylation ability had a higher risk of skin cancer than women.

The associated risk of phthalate exposure, both parent compounds in the home and their metabolites in urine, to childhood allergic and respiratory morbidity, after adjusting for exposures of indoor pollutants, especially bioaerosols, was comprehensively assessed. Levels of five phthalates in settled dust from the homes of 101 children (3–9 years old) were measured, along with their corresponding urinary metabolites. Other environmental risk factors, including indoor CO₂, PM_2.5, formaldehyde, 1,3-β-d-glucan, endotoxin, allergen and fungal levels, were concomitantly examined. Subject’s health status was verified by pediatricians, and parents recorded observed daily symptoms of their children for the week that the home investigation visit took place. Significantly increased level of benzylbutyl phthalate, in settled dust, was associated with test case subjects (allergic or asthmatic children). Higher levels of dibutyl phthalate and its metabolites, mono-n-butyl phthalate, and mono-2-ethylhexyl phthalate were found to be the potential risk factors for the health outcomes of interest. Similarly, indoor fungal exposure remained a significant risk factor, especially for reported respiratory symptoms. The relative contribution from exposure to phthalates and indoor biocontaminants in childhood allergic and respiratory morbidity is, for the first time, quantitatively assessed and characterized. Practical Implications For asthmatic and allergic children living in subtropical and highly developed environments like homes in Taiwan, controlling environmental exposure of phthalates may be viewed as equally important as avoiding indoor microbial burdens, for the management of allergy-related diseases. It is also recognized that multidisciplinary efforts will be critical in realizing the true underlying mechanisms associated with these observations.