A Case-Crossover Analysis of the Association between Exposure to Total PM2.5 and Its Chemical Components and Emergency Ambulance Dispatches in Tokyo

A limited number of studies have investigated the association between short-term exposure to PM_2.5 components and morbidity. The present case-crossover study explored the association between exposure to total PM_2.5 and its components and emergency ambulance dispatches, which is one of the indicators of morbidity, in the 23 Tokyo wards. Between 2016 and 2018 (mean mass concentrations of total PM_2.5 13.5 μg/m³), we obtained data, from the Tokyo Fire Department, on the daily cases of ambulance dispatches. Fine particles were collected at a fixed monitoring site and were analyzed to estimate the daily mean concentrations of carbons and ions. We analyzed 1038301 cases of health-based all-cause ambulance dispatches by using a conditional logistic regression model. The average concentrations of total PM_2.5 over one and the previous day were positively associated with the number of ambulance dispatches. In terms of PM_2.5 components, the percentage increase per interquartile range (IQR) increase was 0.8% for elemental carbon (IQR = 0.8 μg/m³; 95% CI = 0.3-1.3%), 0.9% for sulfate (2.1 μg/m³; 0.5-1.4%), and 1.1% for ammonium (1.3 μg/m³; 0.4-1.8%) in the PM_2.5-adjusted models. This is the first study to find an association between some specific components in PM_2.5 and ambulance dispatches.

Acute Effects of Ambient PM2.5 on All-Cause and Cause-Specific Emergency Ambulance Dispatches in Japan

Short-term health effects of ambient PM_2.5 have been established with numerous studies, but evidence in Asian countries is limited. This study aimed to investigate the short-term effects of PM_2.5 on acute health outcomes, particularly all-cause, cardiovascular, respiratory, cerebrovascular and neuropsychological outcomes. We utilized daily emergency ambulance dispatches (EAD) data from eight Japanese cities (2007–2011). Statistical analyses included two stages: (1) City-level generalized linear model with Poisson distribution; (2) Random-effects meta-analysis in pooling city-specific effect estimates. Lag patterns were explored using (1) unconstrained-distributed lags (lag 0 to lag 7) and (2) average lags (lag: 0–1, 0–3, 0–5, 0–7). In all-cause EAD, significant increases were observed in both shorter lag (lag 0: 1.24% (95% CI: 0.92, 1.56)) and average lag 0–1 (0.64% (95% CI: 0.23, 1.06)). Increases of 1.88% and 1.48% in respiratory and neuropsychological EAD outcomes, respectively, were observed at lag 0 per 10 µg/m³ increase in PM_2.5. While respiratory outcomes demonstrated significant average effects, no significant effect was observed for cardiovascular outcomes. Meanwhile, an inverse association was observed in cerebrovascular outcomes. In this study, we observed that effects of PM_2.5 on all-cause, respiratory and neuropsychological EAD were acute, with average effects not exceeding 3 days prior to EAD onset.

[Acute effects of particulate matter pollution on daily emergency ambulance dispatches due to neurological diseases in one haze polluted city of the North China]

OBJECTIVE

To access the relationship between ambient particulate matter( PM_(2. 5)and PM_(10)) concentration and daily emergency ambulance dispatches due to neurological diseases in one city of the North China.

METHODS

Semi-parametric generalized additive model was used to analyze the relationship between particulate matter( PM_(2. 5)and PM_(10)) concentration and daily emergency ambulance dispatches due to neurological diseases from January 1, 2013 to December 31, 2015 after adjustment for time trends, weather conditions and "days of the week".

RESULTS

An 10 μg/m~3 increase in the lag 03 day concentration of PM_(2. 5)corresponded to increase of 0. 75%( 95% CI0. 34%-1. 17%) in daily emergency ambulance dispatches due to neurological diseases, and an 0. 35%( 95% CI 0. 05%-0. 66%) increase correspondence for PM_(10) in the lag04.

CONCLUSION

Outdoor particulate matter( PM_(2. 5)and PM_(10)) concentration is significantly associated with increased risk of emergency ambulance dispatches due to neurological diseases in the North China.

Effects of temperature and heat waves on emergency department visits and emergency ambulance dispatches in Pudong New Area, China: a time series analysis

BACKGROUND

In July 2013, an extended heat episode with extreme high temperature covered Pudong New Area, the largest district in Shanghai. The current study estimates the impacts of temperature and heat waves on emergency department visits (EDV) and emergency ambulance dispatches (EAD) using time-series approaches in Pudong, from 2011 to 2013.

METHODS

An over-dispersed Poisson generalized additive model was used to examine the association between temperature and EDV and EAD. Heat wave effects with different heat wave definitions considering both the intensity and durations were also estimated.

RESULTS

Immediate effects of temperature on EDV and EAD were detected, after controlling for trends of time and day of week. The exposure-response relationships showed J-shaped curves with higher threshold temperature of EDV than that of EAD visually. When estimating risk changes on heat days compared with non-heat days using different percentiles of daily mean temperature in definition, EAD showed significant increases while non-significant or even negative associations were found for EDV. Heat wave with intensity above the 90th percentile had 2.62% (95% CI: 1.78%, 3.46%) and 0.95% (95% CI: 0.22%, 1.69%) increases in EDV for a duration of at least 2 days and 3 days respectively. The relative increase of EAD were 4.85% (95% CI: 1.42%, 8.39%) and 3.94% (95% CI: 0.88%, 7.10%).

CONCLUSIONS

Varied effects of temperature and heat waves on emergency department visits and emergency ambulance dispatches were investigated. This wider view of the health effect of temperature indicated that interventions for both public health education and health services management should be considered in the study region.