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Medicine » Public Health » "Advanced Topics in Environmental Health and Air Pollution Case Studies", book edited by Anca Maria Moldoveanu, ISBN 978-953-307-525-9, Published: August 29, 2011 under CC BY-NC-SA 3.0 license. © The Author(s).

Chapter 21

Do Socio-Demographic Characteristics Modify the Association Between Air Pollution and Mortality & Morbidity?

By Sabit Cakmak, Sara L. Martin, Claudia Blanco Vidal, Timur Gultekin, Vladislav Brion and Maria Angelica Rubio
DOI: 10.5772/16737

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Map of Chile. The red area on the map has been declared a non-attainment zone because of failure to maintain daily PM10 concentrations below a standard threshold. The area includes nine communities with a population of 1 million inhabitants.
Figure 1. Map of Chile. The red area on the map has been declared a non-attainment zone because of failure to maintain daily PM10 concentrations below a standard threshold. The area includes nine communities with a population of 1 million inhabitants.
Detailed Map of Chile. The locations of ten metropolitan areas highlighted in circles
Figure 2. Detailed Map of Chile. The locations of ten metropolitan areas highlighted in circles
Air pollution levels over time for all nine centres combined.
Figure 3. Air pollution levels over time for all nine centres combined.

Do Socio-Demographic Characteristics Modify the Association Between Air Pollution and Mortality & Morbidity?

Sabit Cakmak1, Sara L. Martin4, Claudia Blanco Vidal2, Timur Gultekin3, Vladislav Brion4 and Maria Angelica Rubio5

1. Introduction

Historical extreme air pollution events such as those experienced in London in the 1950s and 60s clearly demonstrated the potential of ambient air pollution to cause exacerbation of cardio-respiratory disease, manifested as pre-mature mortality and admission to hospital. In the intervening years, considerable efforts have been made to reduce pollution from the combustion of fossil fuels and industrial activity. Although these pollution mitigation strategies have been largely viewed as successful, evidence from population health studies in North America, Europe, South America, Mexico, Asia, Australia and New Zealand continues to identify ambient air quality as a population health concern (Table 1).

ReferenceDataLocationFocus OutcomesSubpop.
Alberdi et al., 19981986-1992Madrid, SpainTSP, SO2 NA, R, CV Sex, Age "/65
Alberdi et al., 1998b1986-1992Madrid, SpainTSP, SO2 NA, R, CV Sex, Age "/65
Anderson et al., 19961987-1992London, EnglandBS, SO2, NO2, O3 NA, R, CV
Bachárová et al., 19961987-1991Slovak RepublicTSP, SO2 A, NA, R, CV
Ballester et al., 19961991-1993Valencia, SpainTSP, SO2 NA, R, CV Age "/70
Borja-Aburto et al., 19971990-1992Mexico City, MexicoO3, SO2, TSPA, NA, R, CV Age
Borja-Aburto et al., 19981993-1995Mexico City, MexicoPM2.5 NA, R, CV Age "/65
Boucher et al., 19961985-1993Salt Lake and Utah counties, U.S.PM10 NA
Burnett et al., 19981980-1994Toronto, CanadaCO, NO2, SO2, TSP, PM2.5,PM10 NA, R, CV, O Age
Burnett et al., 1998b1980-199111 Canadian CitiesCO, NO2, SO2, O3 NA
Burnett et al., 20001986-19968 Canadian CitiesPM2.5,PM10, PM10-2.5 NA
Castillejos et al., 20001992-1995Mexico City, MexicoPM2.5,PM10 PM10-2.5 NA
Chock et al., 20001989-1991Pittsburg, Pennsylvania, U.S.PM2.5,PM10 NA, R, CV Age
Cifuenties et al, 20001988-1996Santiago, ChilePM2.5,PM10, CO, NO2, SO2, O3 NA
Dab et al., 19961987-1992Paris, FranceBS, SO2, O3, NO2, PM13 R morbidity and mortality
Daniels et al., 20001987-199420 cities, U.S.PM10 A, CV
Díaz et al., 19991990-1996Madrid, SpainTSP, SO2, NO2, NOx, O3 R, CV, Emergency hospital admission (94-96)
Dockery et al., 19921985-1986St. Louis, Illinois and Missouri; Roanne county, TennesseePM2.5, PM10,, AerosolsMortality
Fairley, 19901980-1986Santa Clara County, CaliforniaPM10 NA
Fairley, 19991989-1996Santa Clara County, CaliforniaPM2.5 NA, R, CV
ReferenceDataLocationFocus OutcomesSubpop.
Goldberg et al., 20001995-1999Montreal, Quebecpredicted PM2.5 NA, CV, C Age
Gouveia& Fletcher, 20001991-1993São Paulo, BrazilPM2.5,PM10, CO, NO2, SO2, O3 NA, R, CV Socioeco.
sex, age
Hales et al., 20001988-1993Christchurch, New ZealandPM10, NOx, SO2, O3, CONA, R, CV Age "/65
Gwynn et al., 20001988-1990Buffalo, New York, U.S.H+ and SO4 2- PM R, CV and A mortality and morbidity
Hatzakis et al., 19861975-1982Athens, GreeceBS, SO2 Mortality
Hoek et al., 19971983-1991Rotterdam, NetherlandsTSP, BS, SO2, O3, COMortality
Hoek et al., 20001986-1994The NetherlandsPM10, BSNA, R, CV
Hong et al., 19991995-1996Inchon, South KoreaPM10, SO2,CO, O3 NA, R, CV
Ito et al., 19931965-1972London, EnglandBS, S02, Acidic AerosolsMortality
Ito et al., 19951985-1990Cook County, Illinois and Los Angeles County, California, U.S.PM10 Mortality
Ito et al., 19961985-1990Cook County, Illinois, U.S.PM10 R, CV, C Age, Sex, Race
Kelsall et al., 19971974-1988Philadelphia, Pennsylvania, U.S.TSPNA, R, CV Age
Kinney & Özkaynak, 19911970 - 1979Los Angeles, County, California, U.S.Ox, SO4, NO2, CO NA, R, CV
Kinney et al., 19951985-1990Los Angeles, County, California, U.S.PM10 NA
Klemm & Mason, 20001998-1999Atlanta, Georgia, U.S.PM2.5 NAAge ("/65)
Kotesovec et al., 20001982-1994Northern Bohemia, Czech RepublicTSP, SO2 A, CV and C Sex, Age
Krzyzanowski & Wojtyniak 1991/921977-1989Cracow, PolandSO2, PM20 NA, R, CV Sex, Age
Le Tertre et al., 19981987-1990Paris, FranceS02 Mortality
Lee et al., 19991991-1995Seoul and Ulsan, South KoreaTSP, SO2, O3 NA
Lee et al., 20001991-19977 South Korean citiesTSP, SO2, O3 NA
ReferenceDataLocationFocus OutcomesSubpop.
Lipfert et al., 20001992-1995Philadelphia, PennsylvaniaTSPMortality
Lippmann et al., 2000VariousDetroit, Michigan, U.S.H+ and SO4 2- PMMortality and elderly morbidityAge
Lyon et al., 19951985-1992Utah County, U.S.PM10 NA, R, CV, O Age
Machenbach et al., 19931979-1987The NetherlandsS02 Mortality
Mar et al., 20001995-1997Phoenix, Arizona, U.S.PM2.5,PM10, PM10-2.5 NA, R, CV
Michelozzi et al., 19981992-1995Rome, ItalyPM10, SO2, O3, NO2, COMortality
Moolgavak, 20001987-19953 U.S. CountiesPM10, CO, O3 NA, R, CV
Moolgavakar et al., 19951974–1984Steubenville, Ohio, U.S.TSP, SO2 NA
Moolgavakar et al., 1995b1973-1988Philadelphia, Pennsylvania, U.S.TSP, SO2,O3 NA
Morgan et al., 19981989-1993Sydney, AustraliaPM, NO2, O3 NA, R, CV
Ostro, 19951980-1986California, U.S.PM2.5 NA, R, CV
Ostro et al., 19961989-1991Santiago, ChilePM10 NA, R, CV Age "/65
Ostro et al., 19991989-1992Coachella Valley, California, U.S.PM10 NA, R, CV
Ostro et al., 1999b1992-1995Bangkok, ThailandPM10 R, CVAge
Ostro et al., 20001989-1998Coachella Valley, California, U.S.PM10 NA, R, CV
Peters et al., 20001982-1991Coal districts, Czech Republic;Bavarian districts, GermanyTSP, SO2, PM2.5,PM10 NA, R(Czech Republic only), CV
Pope et al., 19921985-1989Utah CountyPM10 NA, R, CV, O
Pope et al., 19961985-1989Utah CountyPM10 NA, R, CV, O
Pope et al., 19991985-1995Wasatch Front, UtahPM10 NA, R, CV, O
Rahlenbeck & Kahl, 19961981-1989East Berlin, GermanyTSP, SO2 NA
Rossi et al., 19991980-1989Milan, ItalyTSP, SO2, NO2, PM13 NA, R, CV
Saldiva et al., 19951990-1991São Paulo, BrazilPM10 NA
Samet et al., 19981973-1980Philadelphia, PennsylvaniaTSP, SO2 NA
ReferenceDataLocationFocus OutcomesSubpop.
Samet et al., 20001987-199420 cities, U.S.PM10 NA, R, CV
Schwartz & Dockery, 19921974–1984Steubenville, OhioTSP, SO2 NA
Schwartz & Dockery, 19961973-1980Philadelphia, PennsylvaniaTSP, SO2 NA, R, CV Age
Schwartz et al., 19901958-1972London, EnglandBS, SO2 Non-traumatic
Schwartz, 19911973-1982Detroit, Michigan, U.S.TSPNA
Schwartz, 19931985-1988Birmingham, Alabama, U.S.PM10 NA
Schwartz, 19941977 - 1982Cincinnati, Ohio, U.S.TSPA, R, CVAge "/65
Schwartz, 20001986-199310 cities, U.S.PM10 MortalitySocioeco.
Schwartz, 2000b1986-199310 cities, U.S.PM10 Mortality Age "/65
Schwartz, 2000c1979-1986Boston, Massachusetts, U.S.PM2.5 A, R, CV
Schwartz, 2000d1974-1988Philadelphia, PennsylvaniaTSP and SO2NA
Simpson et al., 19971987-1993Brisbane, AustraliaPM10, SO2, O3 NA, R, CV Age "/65
Simpson et al., 20001991-1996Melbourne, AustraliaPM2.5,PM10 NA, R, CV Age
Smith et al., 1999VariousAlabama & Illinois, U.S.PM10 MortalityAge "/65
Spix & Wichmann, 19961976-1985Köln, GermanyTSP, SO2, NO2 Mortality
Spix et al., 19931980-1989Erfurt, GermanyTSP, SO2 Mortality
Styer et al., 19951985-1990Utah, U.S.PM10 NA Age, Sex, Race
Sunyer et al., 19961985-1991Barcelona, SpainBS, NO2, SO2, O3 NA, R, CV Age "/70
Szafraniec et al., 19971993-1996Kraków, PolandSO2, PM10 NA, CV Sex
Tobias & Campbell, 19991991-1995Barcelona, SpainBSMortality
Touloumi et al., 19941984-1988Athens, GreeceBS, CO, SO2 Mortality
Touloumi et al., 19961987-1991Athens, GreeceBS, CO, SO2 Mortality
Touloumi et al., 1997Various6 European CitiesNO2, O3 Mortality
Vigotti et al., 19961980-1989Milan, ItalyTSP, SO2 Respiratory morbidity
ReferenceDataLocationFocus OutcomesSubpop.
Wichmann et al., 20001991-2002Erfurt, GermanyCO, NO2, SO2, O3,PM10 Mortality
Wietlishbach et al., 19961984-1989Zurich, Basle and Geneva, SwiterlandTSP, CO, NO2, SO2, O3 NA, R, CV Age "/65
Wojtyniak & Piekarski, 1996VariousCracow, Lodz, Poznan and Wroclaw, PolandSO2, BSNA, R, CV, D
Wordley et al., 19971992-1994Brimingham, U.K.PM10 R,CV morbidity
X. Xu et al., 19941989Dongchen and Xichen, Beijing, ChinaTSP, SO2 NA, R, CV, C
Z. Y. Xu et al., 20001992Shenyang, ChinaTSP, SO2 NA, R, CV, C, O
Zanobetti & Schwartz, 20001986-19934 U.S. citiesPM10 NA Sex, Race, Edu.
Zmirou et al., 19961985-1990Lyon, FranceS02, NO2, O3, PM13 NA, R, CV, D

Table 1.

Selected references examining air quality and health outcomes around the world with information on the years in which data was collected, as well as the location, the compounds, the health outcomes and subpopulations studied. In the compound column BS indicates black smoke and TSP indicates total suspended particulates. Cause of death categories studied in each paper were coded as A (accidental), NA (Non-accidental), R (respiratory including lung and chronic obstructive pulmonary disease), CV (cardiovascular or circulatory diseases), C (cancer), D (digestive system) and O (other).

Previous work that has found increases in morbidity and mortality are associated with both ambient air pollution and low socio-economic status (Dockery & Pop, 2002; Brunekreef & Holgate, 2002; Bascom et al., 1996; Hahn et al., 1996; Carr et al., 1992, Chen et al., 2001).

However, the literature regarding the effect of age, gender, and social status is conflicting with some studies documenting increased susceptibility studies (Cifuentes et al., 1999; Wojtyniak & Wysocki, 1989; Health Effects Institute[HEI], 2000; Pope, 2000 ) and others finding little or no effect (Gouveia & Fletcher, 2000; Samet et al., 2000; Zanobetti et al., 2000). A variety of factors have been implicated in the increased susceptibility to air pollution among the socially disadvantaged including, higher pollutant levels in living or working areas, increased cigarette smoking, fewer dietary fruits and vegetables, and reduced access to medical care (O'Neill et al., 2003, Sexton et al. 1993). However, identification of subgroups which are more susceptible to the effects of air pollution is important for three reasons:

  1. developing targeted intervention programs;

  2. determining whether the air pollution-health effects found in one region can be extrapolated to other geographic regions;

  3. setting effective air pollution policies that reduce risk for the entire population.

This study investigates whether age, gender and an indicator of social status – educational attainment – modify the effect of particulate air pollution on mortality.

2. Methods

2.1. Air pollution data

Daily air pollution data for the nine communities (communas) that make up the Conception Region (Fig. 1.), Tomé, Penco, Talcahuano, Hualpén, Concepción, San Pedro de la Paz, Chiguayante, Lota, and Coronel, were obtained from monitoring stations located within each of the centers (Fig. 2.). We obtained information for the period from 1 January 2000 to 31 December 2009, although some stations had information for only a subset of these dates. The information collected was the average concentration of particulate matter with mass median aerodynamic diameter less than 10 microns (PM10) over 24 hour periods

2.2. Mortality and sociodemographic data

The daily number of non-accidental deaths (ICD-9 <800) in the study areas were obtained from the Instituto Nacional de Estadisticas, the official source of statistical data in Chile from 1 January 2000 to 31 December 2009 for all nine areas. The daily number of hospitalizations were obtained for five of the areas under study: Tomé, Talcahuano, Concepción,, Lota, and Coronel for the period of January 1 2006 to December 31 2007. Age, gender, and individual educational attainment data were obtained from the Departamento de Estadísticas e Información en Salud (DEIS).

2.3. Statistical medhods

We used time series analyses and assumed both a Poisson distribution and that there was a linear association between ambient air pollution and mortality or morbidity on a logarithmic scale (Rupprecht et al., 1995).

Natural splines were created for air pollution concentrations on the day of study with one knot for each of 15, 30, 60, 90, 120, 180, and 365 days of observation. We then selected the model with the number of knots that either minimized the Akaike Information Criteria


Figure 1.

Map of Chile. The red area on the map has been declared a non-attainment zone because of failure to maintain daily PM10 concentrations below a standard threshold. The area includes nine communities with a population of 1 million inhabitants.

(AIC), a measure of model prediction, or maximized the evidence that the model residuals did not display any type of structure, including serial correlation, using Bartlett’s test (Lindstrom & Bates, 1990; Priestly, 2002). We plotted model residuals against time and found neither a pattern nor a significant correlation between air pollution and time. Once we had selected the optimal model for time, we assessed the value of including terms for the twenty-four hour means of temperature, humidity, and barometric pressure. The best meteorological predictors of death were temperature and humidity while humidex (Meterorological Service of Canada, 2000), a composite measure of temperature and humidity, was the best meteorological predictor of morbidity. We considered temperature and humidex readings on the day of death and the day prior to death and accounted for non-linear associations with death by using natural spline functions. Indicator functions for the day-of-the-week were also included. The association between air pollutants and death was tested at lags of zero to seven days and results were presented for the lags which maximized the effect size. Results from each urban center were pooled using a random effects model.


Figure 2.

Detailed Map of Chile. The locations of ten metropolitan areas highlighted in circles

Here we present the increase in relative risk (RR) of mortality or morbidity with 95% confidence intervals for an increase in PM10 concentration equal to the interquartile range of the pollutant’s concentration over the period of study. The interquartile range includes the middle fifty-percent of the exposure data and provides a realistic estimate of the day-to-day changes in the pollutant’s concentration. The interquartile range is a nonparametric measure of the data’s spread and, as such, is not influenced by skewed data, extreme values or outliers which are unstable and infrequently seen. A random effects model was used to pool the estimates of relative risk following a DerSimonian- Laird test for homogeneity among estimates.

3. Results

Regional population sizes varied by over fourfold from 49,923 in Penco to 224,212 in Conception (Table 2). The number of daily deaths varied by four to fivefold between Conception and Penco. In the population of about one million people, there was an average of 15 deaths per day. The twenty-four hour mean concentrations of particulate matter varied by about 50% - 60% between regions with Chiguayante and San Pedro de la Paz reaching the greatest concentrations of PM10 (Table 2).

Risk of mortality from cardiac disease appeared to be particularly sensitive to increases in air pollution with an estimated increase of 26% (7% to 49%). The point estimate for mortality relative risk was somewhat greater in the oldest compared to the youngest age group, however, the effect was not significantly greater for those at least eighty-five years old compared to less than sixty-five (p > 0.05). The point estimates for mortality risk from PM10 were similar for males and females (p > 0.05) indicating a lack of effect modification by sex. The effect of PM10 on mortality was greatest among those with the lower level of educational attainment. An interquartile increase in pollutants among those who did not complete a college or university degree was associated with a 16.8% (3% to 33%) increase in mortality whereas among college and university graduates there was 13% (-1% to 28%) increase, which was not statistically significant. The risk of death associated with air pollution was particularly high among the elderly with low educational attainment with an increase of 19% (3% to 35%).

Population 100,000s Total Mortality Cardiac Mortality Respiratory Mortality PM10
Total Hospitaliza tion Temperature
Tomé 5.470.935
Penco 4.990.681
Talcahuano 17.133.010
Hualpén 8.81.272
Concepción 22.423.487
San Pedro 8.920.975
Chiguayante 9.981.042
Lota 4.891.126
Coronel 10.311.344

Table 2.

Population size, mean daily total mortality, 24-hour mean daily air pollution levels and 24-hour mean weather for nine urban centers in Chile from January 2000 to December 2009. Mean daily total mortality rates and 24 hour mean weather variables are accompanied by their standard deviation, while the interquartile range is reported for the concentration of PM10.

When regions were pooled, an interquartile increase in concentration of PM10 was associated with a 5.5% (0.3% to 11%) increased risk of death from all causes (Table 3).

Relative Risk
MortalityAll Causes1.055 (1.003, 1.109)
Cardiac1.260 (1.065, 1.490)
Respiratory1.041 (1.024, 1.076)
SexMale1.043 (1.020, 1.085)
Female1.061 (1.024, 1.099)
Age< 641.053 (1.013, 1.096)
65 - 741.048 (1.007, 1.089)
85 +1.061 (1.016, 1.107)
Education< College1.168 (1.029, 1.325)
"/ College1.130 (0.998, 1.280)
Ages "/ 85
& lowest educational strata
1.190 (1.031, 1.349)

Table 3.

Increase in relative risk of mortality by age group, sex, educational attainment, associated with an interquartile increase in PM10 adjusted for long-term trends, day-of-the-week, and temperature and humidity for nine urban centers in Chile from January 2000 to December 2009.

The risk of hospitalization from all causes and from respiratory disease showed no evidence of effect modification by age or sex with an increase in air pollution (Table 4). However, risk of hospitalization from cardiac disease was greatest among those 85 years old and greater, with an increase of 23% (6% to 44%) among the elderly versus 3% (-3% to 10%) among those less than 64 years of age; but, similar to risk of hospitalization from all cause and respiratory disease, cardiac disease showed no effect modification by sex.

All Cause RRCardiac RRRespiratory RR
Age All 1.032 (1.011 to 1.053)1.029 (0.983 to 1.077)1.056 (1.005 to 1.111)
< 64 1.037 (1.017 to 1.059)1.033 (0.974 to 1.097)1.067 (1.014 to 1.123)
65 to 74 1.034 (0.996 to 1.074)1.089 (1.006 to 1.178)1.071 (0.945 to 1.214)
75 to 84 1.036 (0.991 to 1.084)1.050 (0.969 to 1.137)1.119 (1.003 to 1.249)
"/ 85 1.048 (0.977 to 1.124)1.232 (1.058 to 1.435)1.081 (0.946 to 1.235)
Sex All 1.032 (1.011 to 1.053)1.029 (0.983 to 1.077)1.056 (1.005 to 1.111)
Females 1.031(1.010 to 1.054)0.998 (0.940 to 1.059)1.046 (0.986 to 1.109)
Males 1.034 (1.007 to 1.062)1.055 (0.998 to 1.116)1.073 (1.006 to 1.144)

Table 4.

Relative Risk (RR) of hospitalization (morbidity) associated with an interquartile increase in concentrations of PM10 adjusted for long-term trends, day-of-the-week, and humidex for the five urban centers in Conception from January 1 2006 to December 31 2007.

4. Discussion

Although progress has been made steadily over time at reducing ambient concentrations of particulate matter (PM10) (Fig.3), the results of this work suggests that there remains a risk to human health from exposure to this pollutant.The burden of mortality and morbidity due to increases particulate matter (PM10) in the short-terms has the greatest influence on the health of those who are elderly with low educational attainment and those with cardiac disease. In general, effect modification was observed by age and by education but not by sex and effect modification was less pronounced for morbidity data than for mortality data. Air quality guidelines that seek to protect the entire population, including high risk subgroups, should consider the greater sensitivity of those who are elderly, have lower educational attainment or suffer from cardiac disease.

4.1. Effect modification by age and educational attainment

Age significantly modified the effect of cardiac morbidity for the five Chilean communities studied here. Modification by age was less pronounced for all cause mortality, all cause morbidity and respiratory morbidity. Similarly, we observed little modification by educational attainment for total mortality. However, we did find that the combination of old age and low educational attainment resulted in elevated risk from air borne particulate matter.


Figure 3.

Air pollution levels over time for all nine centres combined.

Previous work has reported modification of the effect of air pollutants by age (Bell et al., 2005; Pope, 2000; Pope et al., 2002; Spix et al., 1998; Zanobetti et al., 2000). For example, previous work indicated that compared to those under sixty-five years of age, Chileans eighty five years and older were observed to be more than twice as likely to die from acute increases in PM10, and over 50% more likely to die from increases in ozone and SO2 (Cakmak et al., 2009).

Similarly, Bell et al. (2008) reported increased mortality effects in the elderly from ozone in The National Morbidity Mortality and Air Pollution Study of 98 U.S cities

(Bell & Dominici, 2008) and Filleul et al. (2004) reported a greater effect of air pollution mortality in those over sixty-five years old in France, though these effects were not statistical significant (Filleul et al., 2004).

Previous work has also reported effect modification by educational attainment and other indicators of social status (Bell et al., 2008; Forastiere et al., 2009; Dales, 2002; O’Neil et al., 2003; Ou et al., 2008; Prescott & Vestbo, 1999; Zanobetti et al., 2000). For example, in the Harvard Six-Cities and American Cancer Society cohort studies, there was an increased risk of mortality from long-term exposure to particulate matter among those with lower educational attainment (Health Effects Institute, 2000; Pope et al., 2002; Villeneuve et al., 2002). Similarly, in Hamilton, Canada, the non-accidental mortality risk estimates associated with sulphur dioxide and coefficient of haze were greater in areas of the city with lower educational attainment as well as greater employment in manufacturing (Jerrett et al. 2004). However, this finding is far from consistent: no relation to level of education was found in a study of mortality risk estimates from gaseous and particulate air pollution in Hong Kong (Ou et al., 2008); no effect modification by education was found among urban Americans from 98 communities for ozone levels (Bell & Dominici, 2008); and neither a time-series study of 20 U.S (Samet et al., 2000) cities nor one focusing on Vancouver, Canada found social status modified the effect of air pollution on mortality (Villeneuve et al., 2003). Furthermore, a study of São Paulo, Brazil the authors reported that a monotonically increasing effects of air pollution with increasing education (Gouvenia & Fletcher, 2000). This type of conflicting results lead the authors of a systematic review of the Medline database up to May 2006 to state that because of inconsistent findings in both long-term and short-term exposure studies “Current evidence does not yet justify a definitive conclusion that socioeconomic characteristics modify the effects of air pollution on mortality” (Laurent et al., 2009). Nevertheless, here we report that in combination with old age, risk increases with lower educational attainment.

4.2. The influence of social status

There are many possible reasons why one might expect lower socioeconomic position to increase susceptibility to the deleterious effects of air pollution including: increased exposure to the air pollutants of interest, increased exposure to co-pollutants from occupational dusts and fumes and cigarette smoke, fewer dietary fruits and vegetables, and reduced access to medical care and medicines (O’Neill et al., 2003; Sexton et al., 1993; Spix et al., 1998). Unfortunately, information on these variables was not available. However, because the overall effect size is based on the association between daily changes in air pollution and daily changes in mortality or morbidity, these other variables would only confound the overall pollution-illness association if they change day-to-day which is unlikely (Bell et al., 2005). It is possible that these variables differ between the educational groups and may partly account for the between-group estimates of effect found here.

5. Conclusion

We found that the burden of all cause mortality and cardiac morbidity due to increased particulate air pollution is disproportionately experienced by the elderly who have low educational attainment. These findings suggest that the determination of air quality guidelines designed to protect the general population may be insufficient to protect this vulnerable subgroup.


The authors would like to thank Dra. Danuta Rajs Grzebien of the Departamento de Estadísticas e Información de Salud, Ministerio de Salud for providing morbidity data, and Roberto Martínez González and Joyce Vera Bascour from the Secretaría Regional Ministerial del Medio Ambiente Region Metropolitana for providing data and comments.


1 - Dockery DW, Pope CA. 2002Outdoor Particulates. Environmental Epidemiology Oxford University Press, New York.;119 166
2 - B. Brunekreef, S. T. Holgate, 2002Air pollution and health. Lancet;360 1233 1242
3 - R. Bascom, P. A. Bromberg, D. A. Costa, R. Devlin, D. W. Dockery, M. W. Frampton, W. Lambert, J. M. Samet, F. E. Speizer, M. Utell, 1996Health effects of outdoor air pollution. Am J Respir Crit Care Med;153 3 50
4 - R. A. Hahn, E. D. Eaker, N. D. Barker, S. M. Teutsch, W. K. Sosniak, N. Krieger, 1996Poverty and death in the United States. Int J Health Serv; 26 673 690
5 - W. Carr, L. Zeitel, K. Weiss, 1992Variations in asthma hospitalizations and deaths in New York City. Am J Public Health; 82(59):65
6 - Y. Chen, R. Dales, D. Krewski, 2001Asthma and the risk of hospitalization in Canada : the role of socioeconomic and demographic factors. Chest; 119 708 713
7 - Cifuentes L, Vega J, Lave L. 1999 Daily mortality by cause and socio-economic status in Santiago, Chile 1988-1996. Epidemiology; 10:S45
8 - B. Wojtyniak, M. Wysocki, 1989Chronic airways disease in Poland. Recent trends. Chest; 96(3):324S-328S
9 - Health Effects Institute. 2000Reanalysis of the Harvard Six Cities Study and the American Cancer Society Study of Particulate Air Pollution and Mortality.;1 285
10 - Pope CA, 2000III Epidemiology of fine particulate air pollution and human health: biologic mechanisms and who’s at risk? Environ Health Perspect;108 4 713 723
11 - N. Gouveia, T. Fletcher, 2000Time Series analysis of air pollution and mortality: effects by cause, age and socioeconomic status. J Epidemiol Community Health;54 750 755
12 - Samet JM, Dominici F, Curriero FC, Coursac I, Zeger SL. 2000 Fine Particulate Air Pollution and Mortality in 20 U.S. Cities 1987-1994. N Eng J Med; 343 1742 1749
13 - A. Zanobetti, J. Schwartz, D. Gold, 2000Are there sensitive subgroups for the effects of airborne particles? Environ Health Perspect;108 9 841 845
14 - O’Neill, MS, Jerrett M, Kawachi I, Levy JI, Cohen AJ, Gouveia N, Wilkinson P, Fletcher T, Cifuentes L, Schwartz, J, 2003 Workshop on Air Pollution and Socioeconomic Conditions. Health, Wealth, and Air Pollution: Advancing Theory and Methods. Environ Health Perspect; 111 1861 1870
15 - K. Sexton, H. Gong Jr, J. C. I. I. I. Bailar, J. G. Ford, D. R. Gold, W. E. Lambert, MJ Utell, 1993Air pollution health risks: do class and race matter? Toxicology and Industrial Health;9 843 878
16 - G. Rupprecht, H. Patashnick, D. E. Beeson, RN Meyer. Green, MD , 1995A new automated monitor for the measurement of particulate carbon in the atmosphere. In: Particulate Matter: Health and Regulatory Issues. Proceedings of an International Specialty Conference, Pittsburgh, PA, Air and Waste Management Publications Pittsburgh, PA,;309 319
17 - Lindstrom ML, Bates DM. 1990Nonlinear mixed effects models for repeated measures data. Biometrics;46(3):673-687).
18 - Priestly MB. 2002 Spectral Analysis of Time Series Academic Press, San Diego 1981.Meteorological Service of Canada..
19 - CA III Pope, R. T. Burnett, MJ Calle. Thun, EE D. Krewski, K. Ito, G. D. Thurston, 2002Lung Cancer, Cardiopulmonary Mortality, and Long-term Exposure to Fine Particulate Air Pollution. JAMA;287 1132 1141
20 - C. Spix, H. R. Anderson, J. Schwartz, MA Letertre. A. Vigotti, J. M. Vonk, F. Touloumi, T. Balducci, L. Piekarski, A. Bacharova, A. Tobias, Katsouyanni. K. Ponka, 1998Short-term effects of air pollution on hospital admissions of respiratory diseases in Europe: a quantitative summary of APHEA study results. Arch Environ Health;53 54 64
21 - M. L. Bell, F. Dominici, J. M. Samet, 2005A meta-analysis of time-series studies of ozone and mortality with comparison to the national morbidity, mortality, and air pollution study. Epidemiology;16 425 426
22 - S. Cakmak, R. E. Dales, Vidal. C. Blanco, 2009Air Pollution and Mortality in Chile: susceptibility among the elderly. Environ Health Perspect;115 524 527
23 - M. L. Bell, F. Dominici, 2008Effect modification by community characteristics on the short-term effects of ozone exposure and mortality in 98 US communities. Am J Epidemiol;167 986 997
24 - L. Filleul, A. Le Tertre, I. Baldi, J. F. Tessier, 2004Difference in the relation between daily mortality and air pollution among elderly and all-ages populations in southwest France. Environ Res;94 249 253
25 - Ou CQ. Hedley AJ. Chung RY. Thach TQ. Chau YK. Chan KP. Yang L. Ho SY. Wong CM. Lam TH. 2008 Socioeconomic disparities in air pollution-associated mortality. Environmental Research Jan:107[2], 237-244.
26 - F. Forastiere, M. Stafoggia, C. Tasco, S. Picciotto, N. Agabati, G. Cesaroni, CA Perucci, 2009Socioeconomic status, particulate air pollution, and daily mortality: differential exposure or differential susceptibility.;50[3], 208 216
27 - E. Prescott, J. Vestbo, 1999Socioeconomic status and chronic obstructive pulmonary disease. Thorax;54 737 741
28 - R. E. Dales, B. Choi, Y. Chen, M. Tang, 2002Influence of family income on hospital visits for asthma among Canadian school children. Thorax;57 513 517
29 - MS Bell. M. L. O’Neill, N. C. L. A. Ranjit, D. Loomis, N. Gouveia, V. H. Borja-Aburto, 2008Air Pollution and Mortality in Latin America: The Role of Education. Epidemiology.; 19(6): 810-819).
30 - P. J. Villeneuve, M. S. Goldberg, D. Krewski, R. T. Burnett, Y. Chen, 2002Fine particulate air pollution and all-cause mortality within the Harvard Six-Cities Study: variations in risk by period of exposure. Ann Epidemiol;12 568 576
31 - M. Jerrett, R. T. Burnett, J. Brook, P. Kanaroglou, C. Giovis, N. Finkelstein, B. Hutchison, 2004Do socioeconomic characteristics modify the short term association between air pollution and mortality? Evidence from a zonal time series in Hamilton, Canada. J Epidemiol Community Health:58 31 40
32 - P. G. Villeneuve, R. T. Burnett, Y. Shid, D. Krewski, MS Hertzmang. C. Goldberg, Y. Chend, J. Brook, 2003A time-series study of air pollution, socioeconomic status, and mortality in Vancouver, Canada. Journal of Exposure Analysis and Environmental Epidemiology; 13 427 435 doi:10.1038/sj.jea.7500292
33 - Laurent O, Bard D, Filleil L, Segala C. 2009 Effect of socioeconomic status on the relationship between atmospheric pollution and mortality. Journal of Epidemiology & Community Health;61:665-675.
34 - R. J. Klemm, R. M.Jr Mason, Aerosol Research and Inhalation Epidemiological Study (ARIES): 2000Air Quality and Daily Mortality Statistical Modeling- Interim Results. J. Air Waste Manage. Assoc., 50 1433 1439
35 - M. J. Daniels, F. Dominici, J. M. Samet, S. L. Zeger, 2000Estimating Particulate Matter-Mortality Dose-Response Curves and Threshold Levels: An Analysis of Daily Time-Series for the 20 Largest US Cities. Am. J. Epidemiol., 152 397 406
36 - Samet, J.M,; Dominici, F.; Curriero, F.C; Coursac, I.; Zeger, S.L. 2000 Fine Particulate Air Pollution and Mortality in 20 U.S. Cities, 1987-1994. N. Engl. J. Med., 343, 1742-1749343 1742 1749
37 - J. Schwartz, 2000Assessing Confounding, Effect Modification, and Thresholds in the Association between Ambient Particles and Daily Deaths. Environ. Health Perspect., 108 563 568
38 - J. Schwartz, 2000The Distributed Lag between Air Pollution and Daily Deaths. Epidemiol., 11 320 326
39 - R. L. Smith, J. M. Davis, P. Speckman, 1999Assessing the human health risk of atmospheric particles Novartis. Found. Symp., 220 59 72
40 - J. Schwartz, 1993Air Pollution and Daily Mortality in Birmingham, Alabama. Am. J. Epidemiol., 137 1136 1147
41 - J. Schwartz, 2000Harvesting and Long Term Exposure Effects in the Relation between Air Pollution and Mortality.Am. J. Epidemiol., 151 440 448
42 - R. C. Gwynn, R. T. Burnett, G. D. Thurston, 2000A Time-Series Analysis of Acidic Particulate Matter and Daily Mortality and Morbidity in the Buffalo, New York, Region. Environ. Health Perspect., 108 125 133
43 - J. Schwartz, 1994Total Suspended Particulate Matter and Daily Mortality in Cincinnati, Ohio. Environ. Health Perspect., 102 186 189
44 - B. D. Ostro, S. Hurley, M. J. Lipsett, 1999Air Pollution and Daily Mortality in the Coachella Valley, California: A Study of PM10 Dominated by Coarse Particles. Environ. Res., 81 231 238
45 - B. D. Ostro, R. Broadwin, M. J. Lipsett, 2000Coarse and fine particles and daily mortality in the Coachella Valley, California: a follow-up study. J. Expo. Anal. Environ. Epidemiol., 10 412 419
46 - K. Ito, P. L. Kinney, G. D. Thurston, 1995Variations in PM-10 Concentrations within two Metropolitan Areas and their Implications for Health Effects Analyses. Inhal. Toxicol., 7 735 745
47 - K. Ito, G. D. Thurston, 1996Daily PM10/Mortality Associations: An Investigation of At-Risk Subpopulations. J. Expo. Anal. Environ. Epidemiol., 6 79 95
48 - P. Styer, N. Mc Millan, F. Gao, J. Davis, J. Sacks, 1995Effect of Outdoor Airborne Particulate Matter on Daily Death Counts. Environ. Health Perspect., 103 490 497
49 - Moolgavkar, S.H. 2000 Pollution and Daily Mortality in Three U.S. Counties. Environ. Health Perspect. 108, 777-784.
50 - A. Zanobetti, J. Schwartz, 2000Race, Gender, and Social Status as Modifiers of the Effects of PM10 on Mortality. J. Occup. Environ. Med., 42 469 474
51 - J. Schwartz, 1991Particulate Air Pollution and Daily Mortality in Detroit. Environ. Res., 56 204 213
52 - M. Lippmann, K. Ito, A. Nadas, R. T. Burnett, 2000Association of Particulate Matter Components with Daily Mortality and Morbidity in Urban Populations. Health Effects Institute Research Report 95Health Effects Institute: Cambridge, MA,.
53 - D. W. Dockery, J. Schwartz, J. D. Spengler, 1992Air Pollution and Daily Mortality: Associations with Particulates and Acid Aerosols. Environ. Res., 59 362 373
54 - J. Schwartz, D. Dockery, L. M. Neas, 1996Is Daily Mortality Associated Specifically with Fine Particles? J. Air Waste Manage. Assoc., 46 927 939
55 - P. L. Kinney, H. Özkaynak, 1991Associations of Daily Mortality and Air Pollution in Los Angeles County. Environ. Res., 54 99 120
56 - P. L. Kinney, K. Ito, G. D. Thurston, 1995A Sensitivity Analysis of Mortality/PM-10 Associations in Los Angeles. Inhal. Toxicol., 7 59 69
57 - MS Goldberg, J. C. I. I. I. Bailar, R. T. Burnett, J. R. Brook, R. Tamblyn, Y. Bonvalot, P. Ernst, K. M. Flegel, R. K. Singh, M. F. Valois, 2000Identifying Subgroups of the General Population That May Be Susceptible to Short-Term Increases in Particulate Air Pollution: A Time-Series Study in Montreal, Quebec. Health Effects Institute Research Report 97Health Effects Institute, Cambridge, MA,.
58 - J. Schwartz, D. W. Dockery, 1992Increased Mortality in Philadelphia Associated with Daily Air Pollution Concentrations. Am. Rev. Respir. Dis., 145 600 604
59 - S. H. Moolgavkar, E. G. Luebeck, T. A. Hall, E. L. Anderson, 1995Air Pollution and Daily Mortality in Philadelphia. Epidemiol., 6 476 484
60 - J. Schwartz, 2000Daily deaths are associated with combustion particles rather than SO2 in Philadelphia. Occup. Environ. Med., 57 692 697
61 - Samet, J.; Zeger, S.; Kelsall, J.; Xu, J.; Kalkstein, L. 1998 Does Weather Confound or Modify the Association of Particulate Air Pollution with Mortality? An analysis of the Philadelphia Data, 1973-1980. Environ. Res., 77 9 19
62 - Kelsall, J.E.; Samet, J.M.; Zeger, S.L.; Xu, J. 1997 Air Pollution and Mortality in Philadelphia, 1974-1988. Am. J. Epidemiol., 46 750 762
63 - R. E. Wyzga, F. W. Lipfert, 1995Temperature- Pollution Interactions with Daily Mortality in Philadelphia. In Particulate Matter: Health and Regulatory VIP-49Proceedings of an International Specialty Conference, Pittsburgh, Pennsylvania, April 4-6, , 3-42.
64 - F. W. Lipfert, S. C. Morris, R. E. Wyzga, 2000Daily Mortality in the Philadelphia Metropolitan Area and Size-Classified Particulate Matter. J. Air. Waste Manage. Assoc., 50 1501 1513
65 - Mar, T.F.; Norris, G.A.; Koenig, J.Q.; Larson, T.V. 2000 Associations between Air Pollution and Mortality in Phoenix, 1995-1997. Environ. Health Perspect., 108 347 353
66 - D. P. Chock, S. L. Winkler, C. Chen, 2000A Study of the Association between Daily Mortality and Ambient Air Pollutant Concentrations in Pittsburgh, Pennsylvania. J. Air Waste Manage. Assoc., 50 1481 1500
67 - C. A. I. I. I. Pope, R. W. Hill, G. M. Villegas, 1999Particulate Air Pollution and Daily Mortality on Utah’s Wasatch Front. Environ. Health Perspect., 107 567 573
68 - Boucher, K.M.; Lyon, J.L.; Lillquist, D.R. 1996 Daily Mortality and Exposure to PM10 Air Pollution: A Comparison of Salt Lake and Utah Counties, 1985-1993. In Proceedings of the Second Colloquium on Particulate Air Pollution and Human Health, Park City, Utah, May 1-3,; 4 36
69 - B. Ostro, 1995Fine Particulate Air Pollution and Mortality in Two Southern California Counties. Environ. Res., 70 98 104
70 - Fairley, D. 1990 The Relationship of Daily Mortality to Suspended Particulates in Santa Clara County, 1980-1986. Environ. Health Perspect89 159 168
71 - Fairley, D. 1999 Daily Mortality and Air Pollution in Santa Clara County, California: 1989-1996. Environ Health Perspect., 107 637 641
72 - S. H. Moolgavkar, E. G. Luebeck, T. A. Hall, E. L. Anderson, 1995Particulate air pollution, sulfur dioxide and daily mortality: A reanalysis of the Steubenville data. Inhal. Toxicol., 7 35 44
73 - J. Schwartz, D. W. Dockery, 1992Particulate Air Pollution and Daily Mortality in Steubenville, Ohio. Am. J. Epidemiol., 135 12 19
74 - R. T. Burnett, J. R. Brook, S. Cakmak, M. Raizenne, D. Stieb, R. Vincent, D. Krewski, J. R. Brook, O. Philips, H. Özkaynak, 1998The Association Between Ambient Carbon Monoxide Levels and Daily Mortality in Toronto, Canada. J. Air Waste Manage. Assoc., 48 689 700
75 - R. T. Burnett, 1999In National Ambient Air Quality Objectives for Ground-Level Ozone, Science Assessment Document; Canadian Environmental Protection Act Federal- Provincial Advisory Committee Working Group on Air Quality Objectives and Guidelines; Health Canada and Environment Canada: Ottawa,; A1 A8
76 - R. T. Burnett, S. Cakmak, J. R. Brook, 1998The Effect of the Urban Ambient Air Pollution Mix on Daily Mortality Rates in 11 Canadian Cities. Can. J. Public Health., 89 152 156
77 - R. T. Burnett, J. Brook, T. Dann, C. Delocla, O. Philips, S. Cakmak, R. Vincent, M. S. Goldberg, D. Krewski, 2000Association Between Particulate- and Gas-Phase Components Of Urban Air Pollution and Daily Mortality in Eight Canadian Cities. Inhal. Toxicol., 12 (Supplement 4), 15-39.
78 - C. A. I. I. I. Pope, J. Schwartz, M. R. Ransom, 1992Daily Mortality and PM10 Pollution in Utah Valley. Arch. Environ. Health., 47 211 217
79 - J. L. Lyon, M. Mori, R. Gao, 1995Is there a causal association between excess mortality and exposure to PM10 air pollution? Additional analyses by location, year, season and cause of death. Inhal. Toxicol., 7 603 614
80 - C. A. I. I. I. Pope, L. S. Kalkstein, 1996Synoptic Weather Modeling and Estimates of the Exposure-Response Relationship between Daily Mortality and Particulate Air Pollution. Environ. Health Perspect., 104 414 420
81 - V. H. Borja-Aburto, D. P. Loomis, S. I. Bangdiwala, C. M. Shy, R. A. Rascon-Pacheco, 1997Ozone, Suspended Particulates, and Daily Mortality in Mexico City. Am. J. Epidemiol., 258 268
82 - Borja-Aburto, V.H.; Castillejos, M.; Gold, D.R.; Bierzwinski, S.; Loomis, D. 1998 Mortality and Ambient Fine Particles in Southwest Mexico City, 1993-1995. Environ. Health Perspect., 106 849 855
83 - M. Castillejos, V. H. Borja-Aburto, D. W. Dockery, D. R. Gold, D. Loomis, 2000Airborne coarse particles and mortality. Inhal. Toxicol., 12(S1), 61-72.
84 - B. D. Ostro, J. M. Sanchez, C. Aranda, G. S. Eskeland, 1996Air Pollution and Mortality: Results from a Study of Santiago, Chile. J. Expo. Anal. Environ. Epidemiol., 6 97 114
85 - P. H. Saldiva, C. A. I. I. I. Pope, J. Schwartz, D. W. Dockery, A. J. Lichtenfels, J. M. Salge, I. Barone, G. M. Bohm, 1996Air pollution and mortality in elderly people: A time-series study in Sao Paulo, Brazil. Arch. Environ. Health., 50 159 163
86 - G. Touloumi, S. J. Pocock, K. Katsouyanni, D. Trichopolous, 1994Short-term effects of air pollution on daily mortality in Athens: A time-series analysis. Int. J. Epidemiol., 23 957 967
87 - A. Hatzakis, K. Katsouyanni, A. Kalandidi, N. Day, D. Trichopoulos, 1986Short-term effects of air pollution on mortality in Athens. Int. J. Epidemiol., 15 73 81
88 - G. Touloumi, E. Samoli, K. Katsouyanni, 1996Daily mortality and "winter type" air pollution in Athens, Greece- a time series analysis within the APHEA project. J. Epidemiol. Community Health., 50(suppl 1), S47S51.
89 - G. Touloumi, K. Katsouyanni, D. Zmirou, et al. 1997Short-term Effects of Ambient Oxidant Exposure on Mortality: A Combined Analysis within the APHEA Project. Am. J. Epidemiol., 146 177 185
90 - D. Zmirou, J. Schwartz, M. Saez, et al. 1998Time-Series Analysis of Air Pollution and Cause Specific Mortality. Epidemiol., 9 495 503
91 - J. Sunyer, J. Castellsagué, M. Sáez, A. Tobias, J. M. Antó, 1996Air pollution and mortality in Barcelona. J. Epidemiol. Community Health., 50(Suppl 1), S76S80.
92 - A. Tobias, M. J. Campbell, 1999Modelling influenza epidemics in the relation between black smoke and total mortality. A sensitivity analysis. J. Epidemiol. Community Health., 53 583 584
93 - V. Wietlisbach, C. A. I. I. I. Pope, U. Ackermann-Liebrich, 1996Air pollution and daily mortality in three Swiss urban areas. Soz. Präventivmed., 41 107 115
94 - J. Wordley, S. Walters, J. G. Ayres, 1997Short term variations in hospital admissions and mortality and particulate air pollution. Occup. Environ. Med., 54 108 116
95 - L. Bachárová, K. Fandáková, J. Bratinka, M. Budinská, J. Bachár, M. Gudába, 1996The association between air pollution and the daily number of deaths: findings from the Slovak Republic contribution to the APHEA project. J. Epidemiol. Community Health., 50(Suppl 1), S19S21.
96 - M. Krzyzanowski, B. Wojtyniak, 1991Air pollution and daily mortality in Cracow. Public. Health Rev. /92 19 73 81
97 - B. Wojtyniak, T. Piekarski, 1996Short term effect of air pollution on mortality in Polish urban populations- what is different? J. Epidemiol. Community Health., 50(Suppl 1), S36S41.
98 - K. Szafraniec, W. Tęcza, W. Jedrychowski, 1997Long-term and Short-term Changes in Air Pollutants and Mortality: Experience among Inhabitants in Krakow, Poland. In Health Effects of Particulate Matter in Ambient Air: Proceedings of an International Conference, Prague, Czech Republic, 196 202
99 - F. Kotesovec, J. Skorkovsky, J. Brynda, A. Peters, J. Heinrich, 2000Daily Mortality and Air Pollution in Northern Bohemia: Different Effects for Men and Women. Cent. Eur. J. Public Health, 8 120 127
100 - A. Peters, J. Skorkovsky, F. Kotesovec, J. Brynda, C. Spix, H. E. Wichmann, J. Heinrich, 2000Associations between Mortality and Air Pollution in Central Europe. Environ. Health Perspect., 108 283 287
101 - Rahlenbeck, S.I.; Kahl, H. 1996 Air pollution and mortality in East Berlin during the winters of 1981-1989. Int. J. Epidemiol., 25 1220 1226
102 - Spix, C.; Heinrich, J.; Dockery, D.; Schwartz, J.; Völksch, G.; Schwinkowski, K.; Cöllen, C.; Wichmann, H.E. 1993 Air pollution and daily mortality in Erfurt, East Germany, 1980-89. Environ. Health Perspect., 101 518 526
103 - H.E Wichmann, C. Spix, T. Tuch, G. Wolke, A. Peters, J. Heinrich, W. G. Kreyling, J. Heyder, 2000Daily Mortality and Fine and Ultrafine Particles in Erfurt, Germany. Part I: Role of Particle Number and Particle Mass, Health Effects Institute Research Report 98Health Effects Institute: Cambridge, MA,.
104 - C. Spix, H. E. Wichmann, 1996Daily mortality and air pollutants: findings from Köln, Germany. J Epidemiol. Community Health., 50(suppl 1), 52-58.
105 - Schwartz, J.; Marcus, A. 1990 Mortality and Air Pollution in London: A Time Series Analysis. Am. J. Epidemiol. 131, 185-194.
106 - K. Ito, G. D. Thurston, C. Hayes, M. Lippmann, 1993Associations of London, England, Daily Mortality with Particulate Matter, Sulfur Dioxide, and Acidic Aerosol Pollution. Arch. Environ. Health., 48 213 220
107 - Anderson, H.R.; Ponce de Leon, A.; Bland, J.M.; Bower, J.S.; Strachan, D.P. 1996 Air pollution and daily mortality in London: 1987-92. B.M.J., 312 665 669
108 - Zmirou, D.; Barumandzadeh, T.; Balducci, F.; Ritter, P.; Laham, G.; Ghilardi, J.-P. 1996 Short term effects of air pollution on mortality in the city of Lyon, France, 1985-90. J. Epidemiol. Community Health., 50(suppl 1), S30-S35
109 - Alberdi JC, Díaz J, Montero JC, Mirón I. 1998 Daily mortality in Madrid community 1986-1992: Relationship with meteorological variables. Eur J Epidemiol.; 14 571 578
110 - Odriozola. J. C. Alberdi, Jiménez. J. Díaz, Rubio. J. C. Montero, Pérez. I. J. Mirón, Ortiz. M. S. Pajares, Rodrigues. P. Ribera, 1998Air pollution and mortality in Madrid, Spain: a time-series analysis. Int. Arch. Occup. Environ. Health., 71 543 549
111 - J. Díaz, R. García, P. Ribera, J. C. Alberdi, E. Hernández, M. S. Pajares, A. Otero, 1999Modeling of air pollution and its relationship with mortality and morbidity in Madrid, Spain. Int. Arch. Occup. Environ. Health., 72 366 376
112 - W. T. Morris, 1996 Regression analysis of daily mortality and air pollution using real and simulated data; Department of Trade and Industry: London,.
113 - Vigotti, M.A.; Rossi, G.; Bisanti, L.; Zanobetti, A.; Schwartz, J. 1996 Short term effects of urban air pollution on respiratory health in Milan, Italy, 1980-89. J. Epidemiol. Community Health., 50(suppl 1), S71-S75
114 - Rossi, G.; Vigotti, M.A.; Zanobetti, A.; Repetto, F.; Gianelle, V.; Schwartz, J. 1999 Air Pollution and Cause-Specific Mortality in Milan, Italy, 1980-1989. Arch. Environ. Health., 54 158 164
115 - Mackenbach, J.P.; Looman, C.W.N.; Kunst, A.E. 1993 Air pollution, lagged effects of temperature, and mortality: The Netherlands 1979-87. J. Epidemiol.Community Health., 47; 121-126
116 - E. Buringh, P. Fischer, G. Hoek, 2000Is SO2 a causative factor for the PM-associated mortality risks in the Netherlands? Inhal. Toxicol., 12(S1), 55-60.
117 - G. Hoek, B. Brunekreef, A. Verhoeff, J. van Wijnen, P. Fischer, 2000Daily Mortality and Air Pollution in the Netherlands. J. Air Waste Manage. Assoc., 50 1380 1389
118 - Le Tertre, A.; Quénel, P.; Medina, S.; Le Moullec, Y.; Festy, B.; Ferry, R.; Dab, W. 1998 Modélisation des liens court terme entre la pollution atmosphérique et la santé. Un exemple: SO2 et mortalité totale, Paris, 1987-1990. Rev. Épidémiol. Santé Publique., 46 316 328
119 - W. Dab, S. Medina, P. Quénel, et al. 1996Short term respiratory health effects of ambient air pollution: results of the APHEA project in Paris. J. Epidemiol. Community Health., 50(suppl 1), S42S46.
120 - P. Michelozzi, F. Forastiere, D. Fusco, C. A. Perucci, B. Ostro, C. Ancona, G. Pallotti, 1998Air pollution and daily mortality in Rome, Italy. Occup. Environ. Med.., 55 605 610
121 - G. Hoek, B. Groot, J. D. Schwartz, P. Eilers, 1997Effects of ambient particulate matter and ozone on daily mortality in Rotterdam, the Netherlands. Arch. Environ. Health., 52 455 463
122 - F. Ballester, D. Corella, S. Pérez-Hoyos, A. Hervás, 1996Air pollution and mortality in Valencia, Spain: a study using the APHEA methodology. J. Epidemiol. Community Health., 50 527 533
123 - B. Ostro, L. Chestnut, N. Vichit-Vadakan, A. Laixuthai, 1996The Impact of Particulate Matter on Daily Mortality in Bangkok, Thailand. J. Air Waste Manage. Assoc., 49, PM100PM107.
124 - X. Xu, D. W. Dockery, J. Gao, Y. Chen, 1994Air Pollution and Daily Mortality in Residential Areas of Beijing, China. Arch. Environ. Health., 49 216 222
125 - Y. Hong, C. , J. Leem, H. , E. Ha, H. , D. C. Christiani, 1999PM10 Exposure, Gaseous Pollutants, and Daily Mortality in Inchon, South Korea. Environ. Health. Perspect., 107 873 878
126 - J. Lee, T. , D. Shin, Y. Chung, 1999Air Pollution and Daily Mortality in Seoul and Ulsan, Korea. Environ. Health Perspect., 107 149 154
127 - Lee, J.T.; Kim, H.; Hong,Y.C.; Kwan, H.J.; Schwartz, J.; Christiani, D.C. 2000 Air Pollution and Daily Mortality in Seven Major Cities of Korea, 1991-1997. Environ. Res., 84 247 254
128 - Z. Y. Xu, D. G. Yu, L. B. Jing, X. P. Xu, 2000Air Pollution and Daily Mortality in Shenyang, China. Arch. Environ. Health, 55 115 120