The weekly changes in ambient sulfur dioxide, nitrogen dioxide, and temperature were compared with the figures for respiratory infection in children and adults and for absenteeism from day-care centers (DCC), schools, and workplaces during a 1-year period in Helsinki. The annual average level of sulfur dioxide was 21 micrograms/m3 and of nitrogen dioxide 47 micrograms/m3; the average temperature was +3.1 degrees C. The levels of these pollutants and the temperature were significantly correlated with the number of upper respiratory infections reported from health centers. Low temperature also correlated with increased frequency of acute tonsillitis, of lower respiratory tract infection among DCC children, and of absenteeism from day-care centers, schools and workplaces. Furthermore, a significant association was found between levels of sulfur dioxide and absenteeism. After statistical standardization for temperature, no other correlations were observed apart from that between high levels of sulfur dioxide and numbers of upper respiratory tract infections diagnosed at health centers (P = 0.04). When the concentrations of sulfur dioxide were above the mean, the frequency of the upper respiratory tract infections was 15% higher than that during the periods of low concentration. The relative importance of the effects of low-level air pollution and low temperature on health is difficult to assess.
Sudden infant death syndrome (SIDS) affects approximately 1 in 1000 live births and is the most common cause of infant death after the perinatal period.
To determine the influence of air pollution on the incidence of SIDS.
Time-series analyses were performed to compare the daily mortality rates for SIDS and the daily air pollution concentrations in each of 12 Canadian cities during the period of 1984-1999. Serial autocorrelation was controlled for by city, and then the city-specific estimates were pooled. Increased daily rates of SIDS were associated with increases, on the previous day, in the levels of sulfur dioxide (SO2), nitrogen dioxide (NO2), and carbon monoxide but not ozone or fine particles measured every sixth day. Effects persisted despite adjustments for season alone or the combination of daily mean temperature, relative humidity, and changes in barometric pressure for NO2 and SO2 but not carbon monoxide.
Increases in both SO2 and NO2, equivalent to their interquartile ranges, were associated with a 17.72% increase in SIDS incidence.
Ambient SO2 and NO2 may be important risk factors for SIDS.
The effects of low levels of air pollution and weather conditions on the number of patients admitted to hospitals for exacerbation of chronic bronchitis or emphysema (n = 2807) was studied in Helsinki during a 3-year period, 1987-1989. The daily number of admissions via the emergency room was significantly associated with prevailing levels of sulfur dioxide (SO2) and nitrogen dioxide (NO2) in Poisson regressions controlled for weather, season, time trends, and day of the week, whereas the total number of admissions (via the emergency room and otherwise) was not significantly associated with these pollutants. The effect of SO2 was observed only among those under 65 years old; a significant peak of admissions was seen during the same day (RR, 1.31 for a 2.7-fold increase in SO2; 95% CI, 1.01-1.70; P = 0.039), and another after a 3-day lag (RR, 1.39; 95% CI, 1.05-1.86; P = 0.021). The effect of NO2 was strongest after a 6-day lag and was significant only among those over 64 years old (RR, 1.31; 95% CI, 1.03-1.66; P = 0.022). The average of mean 24-hr concentrations of NO2 was 39 micrograms/m3 (0.021 ppm) and that for SO2 was 19 micrograms/m3 (0.0067 ppm). No relationship was found between admissions and the concentrations of total suspended particulates (TSP) or ozone (O3), the temperature, or the relative humidity. However, the number of admissions among those over 64 years of age was significantly lower, irrespective of temperature, during the summer than during other seasons. The mean daily concentration of O3 was fairly low (22 micrograms/m3 or 0.011 ppm), but that of TSP was high, 76 micrograms/m3. the mean temperature was low, +4.7 degrees C. These results suggest that SO2 and NO2 concentrations lower than those given as guidelines in many countries, and lower than previously shown, may increase the incidence of symptoms in some patients with chronic bronchitis or emphysema.
This study aimed to investigate the association between daily air pollution levels and the occurrence of acute respiratory signs and symptoms among people with asthma or asthma-like problems. Thirty eight subjects in the southern Swedish city of Landskrona kept a daily diary for 10 weeks. The daily prevalence of symptoms, supplementary bronchodilator use and peak flow deviations were compared with measurements of environmental nitrogen dioxide (NO2), sulphur dioxide, temperature and humidity in the city. The occurrence of severe asthma, both during the day and during the evening, was significantly positively associated with the concurrent 24 h average concentration of NO2, which never exceeded 72 microg x m(-3). A correlation of borderline significance was found between the use of on-demand medication and the NO2 level. However, peak flow deviations were not associated with air pollution or weather conditions, which may be explained by the beneficial effect of bronchodilators used by 28 of the subjects. The results of this study confirm those of some earlier studies and suggest that aggravation of asthma is related to daily variations in air quality, as indicated by relatively low ambient concentrations of nitrogen dioxide. These results also indicate that it may be appropriate to examine severe asthma symptoms separately.
Determine the risk of premature mortality due to the urban ambient air pollution mix in Canada.
The number of daily deaths for non-accidental causes were obtained in 11 cities from 1980 to 1991 and linked to concentrations of ambient gaseous air pollutants using relative risk regression models for longitudinal count data.
Nitrogen dioxide had the largest effect on mortality with a 4.1% increased risk (p
Comment In: Can J Public Health. 1998 Jul-Aug;89(4):228, 238, 240 passim9735513
Air pollution along the border between Norway and Russia has been recorded since 1974 in Sør-Varanger county (Norway) and since 1985 in Murmansk county (Russia). A more extensive collaboration on the environmental pollution problems in the border region was started in 1988 with the establishment of a joint pollution commission. Sulphur dioxide seems to be the most important pollutant causing both environmental damage and adverse health effects. The recommended highest 6-month mean acceptable value for Norway of 40-60 micrograms/m3 was exceeded for two Russian and one Norwegian station during the winter of 1990/91. About 5% of hourly means exceeded 350 micrograms/m3 at the most polluted Norwegian station. The highest value recorded at the nearest populated area in Norway was 2500 micrograms/m3 (The Norwegian Institute for Air Research). Standardized mortality data suggest an increase in deaths from cancer and cardiovascular disease in two cities with nickel refineries, compared to a control city. Further analysis is required to confirm this.
Iron and steel industry is an important source of air pollution emissions. Few studies have investigated cardiovascular effects of air pollutants emitted from steel plants.
We examined the influence of outdoor air pollution in the vicinity of a steel plant on cardiovascular physiology in Sault Ste. Marie, Canada.
Sixty-one healthy, non-smoking subjects (females/males=33/28, median age 22 years) spent 5 consecutive 8-hour days outdoors in a residential area neighbouring a steel plant, or on a college campus approximately 5 kilometres away from the plant, and then crossed over to the other site with a 9-day washout. Mid day, subjects underwent daily 30-minute moderate intensity exercise. Blood pressure (BP) and pulse rate were determined daily and post exercise at both sites. Flow-mediated vasodilation (FMD) was determined at the site near the plant. Air pollution was monitored at both sites. Mixed-effects regressions were run for statistical associations, adjusting for weather variables.
Concentrations of ultrafine particles, sulphur dioxide (SO2), nitrogen dioxide (NO2) and carbon monoxide (CO) were 50-100% higher at the site near the plant than at the college site, with minor differences in temperature, humidity, and concentrations of particulate matter =2.5 µm in size (PM2.5) and ozone (O3). Resting pulse rate [mean (95% confidence interval)] was moderately higher near the steel plant [+1.53 bpm (0.31, 2.78)] than at the college site, male subjects having the highest pulse rate elevation [+2.77 bpm (0.78, 4.76)]. Resting systolic and diastolic BP and pulse pressure, and post-exercise BP and pulse rate were not significantly different between two sites. Interquartile range concentrations of SO2 (2.9 ppb), NO2 (5.0 ppb) and CO (0.2 ppm) were associated with increased pulse rate [0.19 bpm (-0.00, 0.38), 0.86 bpm (0.03, 1.68), and 0.11 bpm (0.00, 0.22), respectively], ultrafine particles (10,256 count/cm(3)) associated with increased pulse pressure [0.85 mmHg (0.23, 1.48)], and NO2 and CO inversely associated with FMD [-0.14% (-0.31, 0.02), -0.02% (-0.03, -0.00), respectively]. SO2 during exercise was associated with increased pulse rate [0.26 bpm (0.01, 0.51)].
Air quality in residential areas near steel plants may influence cardiovascular physiology.
Selected hematological parameters and erythrocyte deformability indexes for 16 young male military students were compared before and after a period of exposure to heavy pollution. These students lived in Ankara, which has a serious air pollution problem. The mean sulfur dioxide levels measured at a station proximal to the campus where the students lived were 188 micrograms/m3 and 201 micrograms/m3 during first and second measurements, respectively. During the period between the two measurements, the mean sulfur dioxide level was 292 micrograms/m3. Significant erythropoiesis was indicated by increased erythrocyte counts and hemoglobin and hematocrit levels. Methemoglobin percentage was increased to 2.37 +/- 0.49% (mean +/- standard error) from 0.51 +/- 0.23%. Sulfhemoglobinemia was present in six subjects after the period of pollution, but it was not present in any student prior to this period. Significant increases in erythrocyte deformability indexes were observed after the period of pollution, i.e., from 1.13 +/- 0.01 to 1.21 +/0 0.02, implying that erythrocytes were less flexible, which might impair tissue perfusion.
We looked for atypical weather patterns that could confound, and explain large inconsistencies in, conventional estimates of mortality due to SO(2), CO, and smoke. Using Greater London data for 1976-1995 in the linear temperature/mortality range 0-15 degrees C we determined weather patterns associated with pollutants (all deseasonalized) by single regressions of daily temperature, wind, rain, humidity, and sunshine at successive days advance and delay. Polluted days were colder (P0.05) some increase with smoke, perhaps acting as surrogate for PM(10), for which data were too scanty to analyze.