The health effects of biological aerosols on the respiratory system are unclear. The purpose of this study was to clarify the association of airborne particle, protein, and endotoxin with emergency department visits for asthma in Kyoto City, Japan. We collected data on emergency department visits at a hospital in Kyoto from September 2014 to May 2016. Fine (aerodynamic diameter ≤ 2.5 μm) and coarse (≥ 2.5 μm) particles were collected in Kyoto, and protein and endotoxin levels were analyzed. The association of the levels of particles, protein, endotoxin, and meteorological factors (temperature, relative humidity, wind speed, and air pressure) with emergency department visits for asthma was estimated. There were 1 to 15 emergency department visits for asthma per week, and the numbers of visits increased in the autumn and spring, namely many weeks in September, October, and April. Weekly concentration of protein in fine particles was markedly higher than that in coarse particles, and protein concentration in fine particles was high in spring months. Weekly endotoxin concentrations in fine and coarse particles were high in autumn months, including September 2014 and 2015. Even after adjusting for meteorological factors, the concentrations of coarse particles and endotoxin in both particles were significant factors on emergency department visits for asthma. Our results suggest that atmospheric coarse particles and endotoxin are significantly associated with an increased risk of asthma exacerbation.

We recently detected five 2-phenylbenzotriazole (PBTA)-type mutagens (PBTA-1, PBTA-2, PBTA-3, PBTA-4 and PBTA-6) in concentrates from several rivers that flow in geographically different areas in Japan containing textile-related industries. On the basis of synthesis studies, these five PBTA derivatives were deduced to have originated from the corresponding dinitrophenylazo dyes, which are industrial chemicals used in textile dyeing, via reduction and chlorination. 2-[(2-Bromo-4,6-dinitrophenyl)azo]-5-(diethylamino)-4-methoxyacetanilide (Color Index name Disperse Blue 291, CAS registry no. 56548-64-2) and 2-[(2-bromo-4,6-dinitrophenyl)azo]-5-(diallylamino)-4-methoxyacetanilide (Color Index name Disperse Blue 373, CAS registry no. 51868-46-3) are used in textile dyeing and have 2-[(2-bromo-4,6-dinitrophenyl)azo]-4-methoxyacetanilide moieties in their structures, which are thought to be essential for their conversion to mutagenic PBTA derivatives. In the present study we have synthesized 2-[2-(acetyl-amino)-4-(diethylamino)-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-7) and 2-[2-(acetylamino)-4-(diallylamino)-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-8) from Disperse Blue 291 and Disperse Blue 373, respectively, by reduction with iron powder and subsequent chlorination with sodium hypochlorite. Both PBTA-7 and PBTA-8 exerted strong mutagenicity in Salmonella typhimurium TA98 and YG1024 in the presence of S9 mix (43 000 and 1 430 000 revertants/nmol for PBTA-7 and 40 700 and 2 213 000 revertants/nmol for PBTA-8 in TA98 and YG1024). To clarify whether PBTA-7 and PBTA-8 exist in the environment, water samples were collected at seven sites in six rivers flowing through two different regions where textile dyeing industries are located. All water samples were mutagenic in Salmonella typhimurium YG1024 with S9 mix and their potencies ranged from 108 000 to 1 990 000 revertants/g blue rayon. PBTA-7 and PBTA-8 were detected in water samples from both regions at levels of <0.1–101.4 ng/g blue rayon and <0.1–48.9 ng/g blue rayon, respectively. In some samples PBTA-7 and PBTA-8 could contribute up to 15% of the water mutagenicity.