Interactive effects of specific fine particulate matter compositions and airborne pollen on frequency of clinic visits for pollinosis in Fukuoka, Japan.

BACKGROUND: Previous studies have revealed the interactive effects of airborne pollen and particulate matter on the daily consultations for pollinosis, but it is uncertain which compositions are responsible. This study aimed to investigate the interactive effects of specific PM2.5 compositions and airborne pollen on the daily number of clinic visits for pollinosis in Fukuoka. METHODS: We obtained daily data on pollen concentrations, PM2.5 compositions, PM2.5 mass, gaseous pollutants (SO2, NO2, CO, and O3), and weather variables monitored in Fukuoka between February and April, 2002-2012. In total, 73,995 clinic visits for pollinosis were made at 10 clinics in Fukuoka Prefecture during the study period. A time-stratified case-crossover design was applied to examine the interactive effects. The concentrations of PM2.5 and its compositions were stratified into low (<15th percentile), moderate (15th-85th percentile), and high (>85th percentile) levels, and the association between airborne pollen and daily clinic visits for pollinosis was analyzed within each level. RESULTS: We found a significant interaction between specific PM2.5 compositions and airborne pollen. Specifically, the odds ratio of daily clinic visits for pollinosis per interquartile increase in pollen concentration (39.8 grains/cm2) at the average cumulative lag of 0 and 2 days during high levels of non-sea-salt Ca2+ was 1.446 (95% CI: 1.323-1.581), compared to 1.075 (95% CI: 1.067-1.083) when only moderate levels were observed. This result remained significant when other air pollutants were incorporated into the model and was fairly persistent even when different percentile cut-off points were used. A similar interaction was found when we stratified the data according to non-sea-salt SO42- levels. This finding differed from estimates made according to PM2.5 and NO3- levels, which predicted that the effects of pollen were strongest in the lower levels. CONCLUSIONS: Associations between airborne pollen and daily clinic visits for pollinosis could be enhanced by high levels of specific PM2.5 compositions, especially non-sea-salt Ca2+.

Short-term exposure to ambient particulate matter and emergency ambulance dispatch for acute illness in Japan.

Short-term exposure to air pollution may be linked to negative health outcomes that require an emergency medical response. However, few studies have been undertaken on this phenomenon to date. The aim of this study therefore was to examine the association between short-term exposure to ambient suspended particulate matter (SPM) and emergency ambulance dispatches (EADs) for acute illness in Japan. Daily EAD data, daily mean SPM and meteorological data were obtained for four prefectures in the Kanto region of Japan for the period from 2007 to 2011. The area-specific association between daily EAD for acute illness and SPM was explored using generalized linear models while controlling for ambient temperature, relative humidity, seasonality, long-term trends, day of the week and public holidays. Stratified analyses were conducted to evaluate the modifying effects of age, sex and medical conditions. Area-specific estimates were combined using meta-analyses. For the total study period the mean level of SPM was 23.7µg/m(3). In general, higher SPM was associated with a significant increase in EAD for acute illness [estimated pooled relative risk (RR): 1.008, 95% CI: 1.007 to 1.010 per 10µg/m(3) increase in SPM at lag 0-1]. The effects of SPM on EAD for acute illness were significantly greater for moderate/mild medical conditions (e.g. cases that resulted in <3weeks hospitalization or no hospitalization) when compared to severe medical conditions (e.g. critical cases, and cases that led to >3weeks hospitalization or which resulted in death). Using EAD data, this study has shown the adverse health effects of ambient air pollution. This highlights the importance of reducing the level of air pollution in order to maintain population health and well-being.