Differentiating the effects of fine and coarse particles on daily mortality in Shanghai, China

In the paper

“The average concentrations of PM2.5 and PM10-2.5 were 56.4µg/m3 and 52.3µg/m3 in our study period”

• Also stated in: § 3.1 Data description · plain

  “During our research period, the mean daily concentrations of PM2.5 and PM10-2.5 were 56.4µg/m3 and 52.3µg/m3 respectively.”

In the paper

“PM2.5 constituted around 53.0% of the PM10 mass.”

• Also stated in: § 3.1 Data description · plain

  “the ratio of daily concentrations of PM2.5 and PM10 ranged from 12% to 97%, with an average of 53.0%.”

In the paper

“We found that PM2.5 was associated with the death rates from all causes and from cardio-respiratory diseases in Shanghai.”

• Also stated in: § 4. Discussion · plain

  “We found that the current level of PM2.5 was associated with elevated death rates from all causes and from cardio-respiratory diseases in Shanghai.”

In the paper

“For PM10-2.5, the effects were attenuated and less precise.”

In the paper

“Compared with the Global Air Quality Guidelines set by World Health Organization (10µg/m3 for annual mean) and U.S. National Ambient Air Quality Standards (15µg/m3 for annual mean), the PM2.5 level in Shanghai was much higher.”

• Also stated in: § 3.1 Data description · plain

  “Compared with the Global Air Quality Guidelines set by World Health Organization (10µg/m3 for annual mean and 25µg/m3 for 24-hour mean) and U.S. National Ambient Air Quality Standards (15µg/m3 for annual mean and 35µg/m3 for 24-hour mean), the PM2.5 level in Shanghai was much higher.”

In the paper

“Consistent with most prior studies (Englert 2004), we found significant effects of PM2.5 on both total and cardio-respiratory outcomes.”

• Also stated in: § 5. Conclusions · plain

  “In summary, we found significant associations of daily mortality with PM2.5, but not with PM10-2.5 in Shanghai.”

In the paper

“For total and cardiovascular mortality, the exposure–response curves associated with PM2.5 exposure present positive nonlinear relationships, although the risks did not increase monotonically. The curves tend to become nonlinear and flat at lower and higher concentrations (Figures 2a and 2b).”

In the paper

“We did not find significant associations of PM10-2.5 with total and respiratory mortality outcomes; however, PM10-2.5 was marginally associated with cardiovascular mortality (Table 3).”

In the paper

“The effects of PM2.5 on total and cardiovascular mortality were statistically significant in single-day lag 0 and multi-day lag 01 (Figures 1a and 1b).”

In the paper

“For respiratory mortality, the effect of PM2.5 was significant on single-day lag 1 and multi-day lag 01 (Figure 1c).”

In the paper

“For total and cardiovascular mortality, we found significant effects of both PM10 and PM2.5; for respiratory mortality, only PM2.5 had a significant association.”

In the paper

“Of note, we did not find a significant effect of PM10-2.5 on either total or respiratory mortality.”

• Also stated in: § 5. Conclusions · plain

  “In summary, we found significant associations of daily mortality with PM2.5, but not with PM10-2.5 in Shanghai.”

In the paper

“Numerous epidemiological studies during the past 20 years have confirmed that short-term exposure to outdoor air pollution contributes to increased cardiorespiratory mortality and morbidity (Brunekreef and Holgate 2002).”

What the sources say

• Not checked yetcites Brunekreef and Holgate 2002

In the paper

“These characteristics, combined with a different pattern of deposition in the lung, support the hypothesis that PM2.5 and PM10-2.5 may have different biologic effects and toxicity.”

In the paper

“To examine the independent effects of PM2.5 and PM10-2.5, O3 was also controlled in the regression models because our previous study showed that O3 had independent effect on daily mortality in Shanghai and the correlation between PM and O3 was low (Zhang et al. 2006).”

What the sources say

• Not checked yetcites Zhang et al. 2006 source

In the paper

“We did not adjust for sulfur dioxide (SO2) and nitrogen dioxide (NO2) in our regression models because PM was highly correlated with SO2 and NO2 in Shanghai (Zhang et al. 2006) and simultaneously entering SO2 (or NO2) into the models can yield unstable parameter estimates when the pollutants involved suffer high inter-correlation (Roberts 2006).”

What the sources say

• Not checked yetcites Zhang et al. 2006 source
• Not checked yetcites Roberts 2006 source

In the paper

“We only used the actual collected data, and did not fill in the missing data of PM2.5 and PM10-2.5.”

In the paper

“In addition, our measurement was conducted at a fix-site monitoring station under China National Quality Control. The station is mandated to not be in direct proximity to traffic, industrial sources, buildings or residential sources of emissions from the burning of coal-, waste-, or oil. Thus our monitoring results reflect the background urban particle level in Shanghai.”

In the paper

“We used data from the continuous monitoring of PM2.5 and PM10-2.5 in Shanghai and had data for 668 consecutive days.”

In the paper

“In addition to the whole-period (Mar. 4, 2004 to Dec. 31, 2005) analysis, we also did sensitivity analysis excluding days with extremely high or low particle concentrations (the highest and lowest 1% values).”

In the paper

“While many epidemiological studies have reported associations of mortality and morbidity with ambient PM2.5 or PM10 (Pope and Dockery 2006), fewer studies have evaluated associations with PM10-2.5, which is largely due to lack of monitoring data.”

What the sources say

• Not checked yetcites Pope and Dockery 2006

In the paper

“Because the assumption of the linearity between the log of mortality and particles may not be justified, we used the smoothing function to graphically analyze their relations (Bell et al. 2006; Daniels et al. 2004).”

What the sources say

• Not checked yetcites Bell et al. 2006 source
• Not checked yetcites Daniels et al. 2004

In the paper

“For the calculation of 24-hour average concentration of PM10, PM2.5 and PM10-2.5, at least 75% of the one-hour values on that particular day have to be available.”

In the paper

“Shanghai offers advantages for the investigation of the particle-mortality relationship. Our study area, nine urban districts of Shanghai, is densely populated. More than six-million permanent residents reside within 279 square kilometers. In addition, compared with the residents in North America, a lower proportion of Shanghai residents have access to or use air conditioning. Thus, the monitored”

In the paper

“Among the pollutants in the ambient mix, particulate matter (PM) has the most consistent association with mortality (Bell et al. 2004).”

What the sources say

• Not checked yetcites Bell et al. 2004

In the paper

“Generally, the regression results did not change significantly, although the estimated effects of PM2.5 and PM10-2.5 increased slightly after excluding extreme concentrations.”

In the paper

“These studies measured PM2.5 concentrations weekly, with monitoring duration no more than one year.”

In the paper

“Another advantage of our study is the ability to use cumulative exposure to PM, which is not always possible in the United States where PM is often measured every few days.”

In the paper

“Given that it is not easy to determine the optimal values of df for time trend and weather conditions in the models whether from statistical or biological plausibility perspectives, we did sensitivity analysis to test the impact of df selection on the regression results.”

In the paper

“Clearly, the changes of df for time trend (within the range of 5-25) and for weather conditions (within the range of 3-12) do not affect the regression results much, which suggest that our findings on the effects of particle concentrations on total morality are relatively robust in this respect.”

In the paper

“The resulting measurement error may have implications for interpreting the effect of particles (Zeger et al. 2000), although a study suggested that this measurement error would generally tend to bias estimates downward (Samet et al. 2000).”

What the sources say

• Not checked yetcites Samet et al. 2000

In the paper

“Subjects who develop COPD, an important cause of respiratory mortality, may have weakened antioxidant defenses (Rahman et al. 1996), and PM2.5 can produce oxidative stress, in part because of lung inflammation (Dagher et al. 2005; Zeka et al. 2006).”

What the sources say

• Not checked yetcites Dagher et al. 2005 source
• Not checked yetcites Zeka et al. 2006 source

In the paper

“These findings provide possible pathways by which PM2.5 can affect the cardiovascular system.”

In the paper

“For instance, Costa et al found that the in vivo pulmonary toxicity of urban particles varied with size, with the greatest toxicity from particles <1.7µm and the lowest toxicity from those >3.5µm (Costa and Dreher 1997).”

What the sources say

• Not checked yetcites Costa and Dreher 1997

In the paper

“We only adjusted for the current-day weather conditions; previous study suggests that the acute effect of PM on daily mortality is robust to the lag structure of weather conditions (Samet et al. 2000).”

What the sources say

• Not checked yetcites Samet et al. 2000

In the paper

“For example, ambient particles have been associated with increased plasma viscosity (Peters et al. 1997), sequestration of red cells in the circulation (Seaton et al. 1999), and indicators of cardiac autonomic dysfunction including increased heart rate, decreased heart rate variability, and increased cardiac arrhythmias (Dockery 2001).”

What the sources say

• Not checked yetcites Peters et al. 1997 source

In the paper

“However, some studies suggested that the daily population average concentrations of fine particles derived from indoor sources are approximately independent of ambient levels (Wilson and Suh 1997).”

What the sources say

• Not checked yetcites Wilson and Suh 1997

In the paper

“Local PM level, population sensitivity to PM, age distribution and especially different particle components may strongly affect the exposure-response relationships.”

In the paper

“For example, ambient particles have been associated with increased plasma viscosity (Peters et al. 1997), sequestration of red cells in the circulation (Seaton et al. 1999), and indicators of cardiac autonomic dysfunction including increased heart rate, decreased heart rate variability, and increased cardiac arrhythmias (Dockery 2001).”

What the sources say

• Not checked yetcites Dockery 2001 source

In the paper

“For example, ambient particles have been associated with increased plasma viscosity (Peters et al. 1997), sequestration of red cells in the circulation (Seaton et al. 1999), and indicators of cardiac autonomic dysfunction including increased heart rate, decreased heart rate variability, and increased cardiac arrhythmias (Dockery 2001).”

What the sources say

• Not checked yetcites Seaton et al. 1999 source

In the paper

“Earlier simulation studies have shown that various regression models and parameter setting in the models (e.g. df selection, convergence criteria) would affect the regression coefficients (Dominici et al. 2002; Peng et al. 2006).”

What the sources say

• Not checked yetcites Dominici et al. 2002 source
• Not checked yetcites Peng et al. 2006 source

In the paper

“This is consistent with most prior studies (Anderson et al. 2001; Fairley 1999; Klemm and Mason 2000; Klemm et al. 2000; Lipfert et al. 2000; Ostro et al. 2000; Schwartz et al. 1996; Villeneuve et al. 2003), but in contrast to several others (Burnett et al. 2000; Cifuentes et al. 2000; Mar et al. 2000).”

What the sources say

• Not checked yetcites Anderson et al. 2001 source
• Not checked yetcites Fairley 1999 source
• Not checked yetcites Klemm and Mason 2000

In the paper

“COPD patients may also be susceptible to particulate air pollution because obstructive airways disease leads to enhanced deposition of inhaled particles (Kim and Kang 1997).”

What the sources say

• Not checked yetcites Kim and Kang 1997

In the paper

“When this is true, failure to measure indoor sources will not introduce further bias in the estimated effects of ambient particles (Zeger et al. 2000).”

What the sources say

• Not checked yetcites Zeger et al. 2000 source

In the paper

“Compared with studies in Europe and North America, the data we collected were also limited by virtue of the single city and limited time period.”

In the paper

“Subjects who develop COPD, an important cause of respiratory mortality, may have weakened antioxidant defenses (Rahman et al. 1996), and PM2.5 can produce oxidative stress, in part because of lung inflammation (Dagher et al. 2005; Zeka et al. 2006).”

What the sources say

• Not checked yetcites Rahman et al. 1996 source

In the paper

“The resulting measurement error may have implications for interpreting the effect of particles (Zeger et al. 2000), although a study suggested that this measurement error would generally tend to bias estimates downward (Samet et al. 2000).”

What the sources say

• Not checked yetcites Zeger et al. 2000 source