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PubMed2005

Correlations between mutagenic activity of organic extracts of airborne particulate matter, NOx and sulphur dioxide in southern Germany: results of a two-year study.

GOALS, SCOPE AND BACKGROUND: Among other substances, sulphur dioxide (SO2), nitric oxide (NO) and nitrogen dioxide (NO2) are parameters which are routinely measured to describe basic air quality. Organic extracts of airborne particulate matter contain mutagenic chemical compounds of different origins. The aim of the study was to find correlations between routine monitoring data and mutagenic activity of organic extracts of simultaneously drawn samples. METHODS: Specimens were collected over a period of two years at 8 sampling sites in south-west Germany. Simultaneously, concentrations of NO, NO2, and SO2 were measured on-line within the framework of the official air monitoring network of Baden-Württemberg, Germany. Dust samples were collected for biotesting using high volume air samplers equipped with glass fibre filters. After sampling was completed, filters were extracted and samples were prepared for biological testing. Mutagenic activity was tested by means of the plate incorporation assay (Ames test) using S. typhimurium TA98 and TA100 tester strains. During the first year of the study, all tests have been performed with and without metabolic activation. Additionally, a series of tests has been performed in parallel with TA98 and TA98NR. RESULTS AND DISCUSSION: Comparison of Ames test data obtained with and without metabolic activation indicates no statistically significant difference between both methods. Therefore, during the second year of the study, all tests have been performed without metabolic activation. Average yearly activities at the sampling sites were between 1 and 27 Revertants per m3 (Rev/m3). High activities were preferably found at congested sites (Karlsruhe, up to 95 Rev/m3). However, peak values of over 100 Rev/m3 were found in other places where pollution by traffic is significantly lower. The reason for these high level values is not evident. Tests performed using TA98NR tester strain indicate a significant share (average 31%) of compounds requiring activation by nitroreductase for mutagenic activity. Average mutagenic activity can be correlated to routine monitoring parameters. Comparison of averaged data for particular sampling sites indicates significant correlation between nitric oxide and mutagenic activity in TA98 (r2=0.90), while correlation between nitrogen dioxide (0.84) or sulphur dioxide (0.52) and mutagenic activity is weaker. For TA100, correlations are generally weaker than for TA98. Comparison of data for mutagenic activity and routine monitoring data of distant sites being sampled simultaneously shows parallel behaviour. CONCLUSIONS: Results from this study show that mutagenic activity can be compared to seasonal and local variations of gaseous indicator air pollutants. Tester strain TA98 generally shows the best correlations. Although pollution by particle-bound mutagenic substances is significantly higher during the cold season than during summer on average, mutagenic activity of airborne dust is not a continuous effect. During winter, peak levels as well as low pollution periods can occur. Even during winter time mutagenic activity can reach very low levels typical for summertime. Comparison of results for distant sampling sites where samples have been collected simultaneously indicate that 'classical' indicators of air pollution and bacterial mutagenicity of organic extracts from airborne particulate matter are influenced by connected effects. Seasonal trend of mutagenic activity, in particular, is similar to the concentrations of nitrogen oxide. NO is a strong indicator for vehicle exhaust gases. It is concluded that the average mutagenic activity at particular sites can be estimated using NO concentrations as an indicator.

Air Pollutants↗

PubMedDate not supplied

Short-term effects of air pollution on hospital admissions of respiratory diseases in Europe: a quantitative summary of APHEA study results. Air Pollution and Health: a European Approach.

The Air Pollution and Health: a European Approach (APHEA) project is a coordinated study of the short-term effects of air pollution on mortality and hospital admissions. Five West European cities (i.e., London, Amsterdam, Rotterdam, Paris, Milano) contributed several years of hospital admissions data for all respiratory causes. In the current study, the authors describe the results obtained from the quantitative pooling (meta-analysis) of local analyses. The diagnostic group was defined by ICD 460-519. The age groups studied were 15-64 y (i.e., adults) and 65+ y (elderly). The air pollutants studied were sulfur dioxide; particles (i.e., Black Smoke or total suspended particles); ozone; and nitrogen dioxide. The pollutants were obtained from existing fixed-site monitors in a standardized manner. We used Poisson models and standardized confounder models to examine the associations between daily hospital admissions and air pollution. We conducted quantitative pooling by calculating the weighted means of local regression coefficients. We used a fixed-effects model when no heterogeneity could be detected; otherwise, we used a random-effects model. When possible, the authors investigated the factors correlated with heterogeneity. The most consistent and strong finding was a significant increase of daily admissions for respiratory diseases (adults and elderly) with elevated levels of ozone. This finding was stronger in the elderly, had a rather immediate effect (same or next day), and was homogeneous over cities. The elderly were affected more during the warm season. The Sulfur dioxide daily mean was available in all cities, and it was not associated consistently with an adverse effect. Effects were present in areas in which more than one station was used in the assessment of daily exposure. Some significant associations were observed, although no conclusion that related to an overall particle effect could be drawn. The effect of Black Smoke was significantly stronger with high nitrogen dioxide levels on the same day, but nitrogen dioxide itself was not associated with admissions. The ozone results were in good agreement with the results of similar U.S. studies. The coherence of the results of this study and other results gained under different conditions strengthens the argument for causality.

Adolescent↗

PubMed2004

Mechanistic insight into the peroxidase catalyzed nitration of tyrosine derivatives by nitrite and hydrogen peroxide.

Peroxidases perform the nitration of tyrosine and tyrosyl residues in proteins, in the presence of nitrite and hydrogen peroxide. The nitrating species is still unknown but it is usually assumed to be nitrogen dioxide. In the present investigation, the nitration of phenolic compounds derived from tyrosine by lactoperoxidase and horseradish peroxidase was studied, with the aim of elucidating the mechanism of the reaction. The results indicate that nitrogen dioxide cannot be the only nitrating species and suggest the presence of two simultaneously operative pathways, one proceeding through enzyme-generated nitrogen dioxide and another through a more reactive species, assumed to be complexed peroxynitrite, which is generated by reaction of hydrogen peroxide with the enzyme-nitrite complex. The importance of the two pathways depends on peroxide and nitrite concentrations. With lactoperoxidase, nitration through the highly reactive intermediate is preferred except at very low nitrite concentration, while with horseradish peroxidase, the nitrogen dioxide driven mechanism is preferred except at very high nitrite concentration. The preferred mechanism for the two enzymes is that operative in the physiological nitrite concentration range.

Animals↗

PubMed2006

The relationship between changes in daily air pollution and hospitalizations in Perth, Australia 1992-1998: a case-crossover study.

A case-crossover study was undertaken to investigate the relationship between daily air pollutant concentrations and daily hospitalizations for selected disease categories in Perth, Western Australia. Daily measurements of particles (measured by nephelometry and PM2.5), photochemical oxidants (measured as ozone), nitrogen dioxide (NO2) and carbon monoxide (CO) concentrations were obtained from 1992 to 1998 via a metropolitan network of monitoring stations. Daily PM2.5 concentrations were estimated using monitored data, modelling and interpolation. Hospital morbidity data for respiratory, cardiovascular (CVD), gastrointestinal (GI) diseases, chronic obstructive pulmonary diseases (COPD) excluding asthma; pneumonia/influenza diseases; and asthma were obtained and categorized into all ages, less than 15 years and greater than 65 years. Gastrointestinal morbidity was used as a control disease. The data were analyzed using conditional logistic regression. The results showed a small number of significant associations for daily changes in particle concentrations, nitrogen dioxide and carbon monoxide for the respiratory diseases, CODP, pneumonia, asthma and CVD hospitalizations. Changes in ozone concentrations were not significantly associated with any disease outcomes. These data provide useful information on the potential health impacts of air pollution in an airshed with very low sulphur dioxide concentrations and lower nitrogen dioxide concentrations commonly found in many other cities.

Air Pollution↗

PubMed2005

Decreased number of sperms and Sertoli cells in mature rats exposed to diesel exhaust as fetuses.

This study was conducted to follow up the effects of fetal exposure to diesel exhaust on testicular cell numbers and daily sperm production in adulthood. Thirty-six pregnant rats were divided into five groups: groups exposed to total diesel-engine exhaust containing 1.71 mg/m3 particulate matter and 0.80 ppm nitrogen dioxide (high dose) or 0.17 mg/m3 particulate matter and 0.10 ppm nitrogen dioxide (low dose); groups exposed to filtered exhaust without particles containing 0.80 (high dose) or 0.10 (low dose) ppm nitrogen dioxide; and a group exposed to clean air. Exhaust exposure was performed from gestational day 7 to delivery. The numbers of daily produced sperm, spermatids and Sertoli cells in the diesel-exhaust-exposed groups were significantly lower than those in the control group on day 96 after birth. The ratio of spermatids/Sertoli cells and the follicle-stimulating hormone levels in the exposed groups were significantly higher. The present study provides evidence for the first time that mature rats exposed to diesel exhaust during fetus show a decrease in the daily production of sperm due to an insufficient number of Sertoli cells. As both the exhaust-exposed groups showed almost the same reactions toward the inhalation, the gaseous phase must have included the responsible toxicants.

Animals↗

PubMed2006

The air quality impacts of road closures associated with the 2004 Democratic National Convention in Boston.

BACKGROUND: The Democratic National Convention (DNC) in Boston, Massachusetts in 2004 provided an opportunity to evaluate the impacts of a localized and short-term but potentially significant change in traffic patterns on air quality, and to determine the optimal monitoring approach to address events of this nature. It was anticipated that the road closures associated with the DNC would both influence the overall air pollution level and the distribution of concentrations across the city, through shifts in traffic patterns. METHODS: To capture these effects, we placed passive nitrogen dioxide badges at 40 sites around metropolitan Boston before, during, and after the DNC, with the goal of capturing the array of hypothesized impacts. In addition, we continuously measured elemental carbon at three sites, and gathered continuous air pollution data from US EPA fixed-site monitors and traffic count data from the Massachusetts Highway Department. RESULTS: There were significant reductions in traffic volume on the highway with closures north of Boston, with relatively little change along other highways, indicating a more isolated traffic reduction rather than an across-the-board decrease. For our nitrogen dioxide samples, while there was a relatively small change in mean concentrations, there was significant heterogeneity across sites, which corresponded with our a priori classifications of road segments. The median ratio of nitrogen dioxide concentrations during the DNC relative to non-DNC sampling periods was 0.58 at sites with hypothesized traffic reductions, versus 0.88 for sites with no changes hypothesized and 1.15 for sites with hypothesized traffic increases. Continuous monitors measured slightly lower concentrations of elemental carbon and nitrogen dioxide during road closure periods at monitors proximate to closed highway segments, but not for PM2.5 or further from major highways. CONCLUSION: We conclude that there was a small but measurable influence of DNC-related road closures on air quality patterns in the Boston area, and that a low-cost monitoring study combining passive badges for spatial heterogeneity and continuous monitors for temporal heterogeneity can provide useful insight for community air quality assessments.

Air Pollutants↗

PubMed2001

Effects of the inhalation of diesel exhaust, Kanto loam dust, or diesel exhaust without particles on immune responses in mice exposed to Japanese cedar (Cryptomeria japonica) pollen.

To assess the potential enhancement by air-pollutants of immune responses in mice, especially with regard to allergen-specific immunoglobulin E (IgE) antibody production, female BDF(1) mice (60 mice in each group) were exposed to diesel exhaust (particles, 3.24 mg/m(3); nitrogen dioxide, 1.0 ppm: DE group), Kanto loam dust (particles, 3.29 mg/m(3); nitrogen dioxide, 0.01 ppm: KLD group), diesel exhaust without particles (particles, 0.01 mg/m(3); nitrogen dioxide, 1.1 ppm: DEG group), or clean air (pollen and control groups) for 16 h/day, 5 days/wk for 24 wk, as well as to Japanese cedar pollen (JCP) (around 550,000 grains of JCP/m(3)) for 2 days/wk in the same period. The control group was exposed to clean air alone throughout the experiment. The mean values for Japanese cedar pollen allergens (JCPAs)-specific immunoglobulin E (IgE) antibody titers in mice sera measured by enzyme-linked immunosorbent assay (ELISA) in the DE, KLD, and DEG groups were higher than that for the pollen alone group, but not significantly, after both 12 and 24 wk of exposure time. The percentages of animals expressing more than the minimum ELISA titer of JCPAs-specific IgE antibodies in each group were 22% (DE and pollen groups) and 27% (KLD and DEG groups) of the totals at wk 12, and no statistical differences were observed among the groups. However, at wk 24 in the DE, KLD, and DEG groups the responders comprised 73%, 63%, and 67%, respectively, significantly higher than the 33% for the pollen alone group. No significant differences were observed among the DE, KLD, and DEG groups. A slight dose-dependent increase of proliferative responses of mouse cervical lymph node cells to JCPAs in both DE and KLD groups was observed, but not in the DEG group. Remarkable decrease of interferon-gamma and significant increase of interleukin-4 in the nasal lavage fluid were apparent after DE or DEG exposure, but not in the KLD group. These results suggest that these air pollutants (DE, KLD, and DEG) enhance the production of IgE antibodies in mice, with similar adjuvant activities in each case. Furthermore, in the early phase of exposure in which sensitization occurred with exposure to pollen, the fine particles and gas components are considered to have exhibited different enhancing mechanisms in mice as follows: (1) The fine particles augmented production of IgE antibodies through activation of T lymphocytes, and (2) the gas components exhibited almost no action on T lymphocytes, but directly induced disorders of the cytokine network and augmented the production of IgE antibodies.

Air Pollutants↗

PubMed1975

Air pollution and health.

The effects of air pollution on human health are reviewed. Data from toxicology, epidemiology, clinical and laboratory exposures are presented as a basis for an emerging etiology. Sulfur dioxide, suspended particulates, nitrogen dioxide, photochemical oxidants, and carbon monoxide are examined as stress agents to the cardio-pulmonary system.

Air Pollutants↗

PubMed1998

Air pollution and hospital admissions in Sydney, Australia, 1990 to 1994.

OBJECTIVES: This study examined the effects of outdoor air pollutants on daily hospital admissions in Sydney, Australia. METHODS: A time-series analysis of counts of daily hospital admissions and outdoor air pollutants (1990 to 1994) was performed, by means of Poisson regression that allowed for overdispersion and autocorrelation. RESULTS: An increase in daily maximum 1-hour concentration of nitrogen dioxide from the 10th to the 90th percentile was associated with an increase of 5.29% (95% confidence interval = 1.07, 9.68) in childhood asthma admissions and 4.60%(-0.17,9.61) in chronic obstructive pulmonary disease (COPD) admissions. A similar increase in daily maximum 1-hour particulate concentration was associated with an increase of 3.01% (-0.38, 6.52) in COPD admissions. An increase from the 10th to the 90th percentile in daily maximum 1-hour nitrogen dioxide, daily maximum 1-hour ozone, and daily mean particulate was associated with an increase in heart disease admissions among those 65 years and older of 6.71% (4.25, 9.23), 2.45% (-0.37, 5.35), and 2.82% (0.90, 4.77), respectively. Heart disease and childhood asthma were primarily associated with nitrogen dioxide; COPD was associated with both nitrogen dioxide and particulates. CONCLUSIONS: Current levels of air pollution in Sydney are associated with increased hospitalization for respiratory and heart disease.

Adolescent↗

PubMed1995

Air pollution and asthma: molecular mechanisms.

Air pollution, in particular that generated by road traffic, is a matter of rising public concern and has been implicated in the worsening of asthma. In this article, the evidence that air pollutants (particularly sulphur dioxide, ozone and nitrogen dioxide) can affect the airways of asthmatic patients is reviewed, and the possible molecular mechanisms that may link air pollution to increased inflammation in the airways are discussed. Airway epithelial cells may respond to oxidant pollutants by the activation of transcription factors, such as nuclear factor kappa B, resulting in increased transcription of genes for certain cytokines, such as interleukin 8 and inflammatory enzymes, such as inducible nitric oxide synthase and cyclo-oxygenase.

Air Pollutants↗

PubMed1994

Health effects of outdoor air pollution.

One hundred sixty-four million Americans live in areas that fail to meet the National Ambient Air Quality Standards for six common air pollutants: particulates, sulfur dioxide, carbon monoxide, nitrogen dioxide, ozone and lead. The impact of these pollutants on health is significant. A Pollutant Standards Index (PSI) ranging from 0 to 500 is used to monitor air quality. When the PSI exceeds 100, the acceptable federal standard has been exceeded by at least one of four measured pollutants. When this occurs, all individuals should be advised to curtail physical activity between late morning and sunset and to remain indoors if possible. Athletes should be encouraged to train in the early morning, when photochemicals are usually at their lowest levels.

Air Pollutants↗

PubMed1979

Certain biochemical changes in the trachea, lungs, and heart of squirrels exposed to three principal air pollutants.

The fate of total lipids, proteins and carbohydrates in the trachea, lungs, and heart of the common ground squirrel, Funambulus pennanti, have been determined after separate exposure to three principal air pollutants, carbon monoxide (CO), sulphur dioxide (SO2), and nitrogen dioxide (NO2). Exposure to all of these gases produced edematous conditions; however, the moisture content of heart muscle was reduced. Carbon monoxide (CO) and NO2 are more toxic to pulmonary lipids than SO2. The lipid of the heart decreased, least effects noted with SO2 treatment. Mechanical properties of the lungs were changed by alteration of the lung lipids causing changes in the surface tension. Changes in protein content were caused by altered membrane permeability. Comparative data on the carbohydrates indicated adverse effects by the pollutants.

Air Pollutants↗

PubMedDate not supplied

Respiratory effects of air pollutants among asthmatics in central Taiwan.

The authors investigated the relationship between respiratory effects and air pollutants among asthmatics in central Taiwan. A total of 12,926 subjects were selected from 8 junior high schools. Data about monthly hospital admissions for respiratory illnesses were collected over a period of 1 yr from the National Insurance Bureau. Data included how frequently subjects purchased medication and the respiratory symptoms recorded by clinic and hospital personnel. Pulmonary function tests were administered to 20% of the total study population, which was selected randomly. Data about monthly levels of air pollutants (i.e., particulate matter 10 pm and less [PM10], ozone [O3], sulfur dioxide [SO2], and nitrogen dioxide [NO2]) were provided by Taiwan's Environmental Protection Agency. The prevalence rates of asthma were correlated significantly with NO2 (r = .63) and 03 (r = .51) concentrations. Levels of NO2 and PM10 were correlated significantly with monthly hospital admissions. Forced vital capacity, forced expiratory volume in 1 sec, and peak expiratory flow for asthmatics in central Taiwan were 6-11% lower than normal predicted values for the general Taiwanese student population, adjusted for age, height, and weight. In conclusion, the increased risk of asthma and the frequency of monthly hospital admissions among asthmatics may be correlated positively with pollution levels-especially NO2 and PM10. air pollutants, asthma, mon

Adolescent↗

PubMed1992

Respiratory disease surveillance in Hungary.

In October 1989, the Hungarian National Institute of Hygiene initiated the Children's Acute Respiratory Morbidity (CHARM) Surveillance System to assess the association between nine reportable respiratory diseases and air pollution. The weekly number of physician-diagnosed, reportable respiratory diseases among four age groups of children (less than 1, 1-2, 3-5, and 6-14 years) was tabulated for Sopron, a city with 60,000 residents. We calculated the proportion of diseases occurring during weeks with low, moderate, and high sulfur dioxide (SO2) and nitrogen dioxide (NO2) concentrations. The weekly averages of the 24-hour median SO2 concentrations were divided into thirds at less than or equal to 17.6, greater than 17.6 to less than or equal to 26.3, and greater than 26.3 micrograms/m3 (range: 0.9-79.6 micrograms/m3), and the NO2 concentrations at less than or equal to 29.8, greater than 29.8 to less than or equal to 44.1, and greater than 44.1 micrograms/m3 (range: 4.2-90.1 micrograms/m3). During 1990, 11,474 respiratory disease cases occurred among the 4,020 children less than 15 years of age living in Sopron and monitored by the CHARM system. The two most frequently reported disease categories were rhinitis/tonsillitis/pharyngitis (71.5%) and acute bronchitis (8.5%). Sixty-seven percent of pneumonia cases occurred when SO2 concentrations were highest. We found no association between levels of NO2 and respiratory diseases. The CHARM Surveillance System may characterize more fully which groups of children develop particular respiratory diseases following exposure to air pollution.

Acute Disease↗

PubMed2000

Validity of annoyance scores for estimation of long term air pollution exposure in epidemiologic studies: the Swiss Study on Air Pollution and Lung Diseases in Adults (SAPALDIA).

In air pollution epidemiology, estimates of long term exposure are often based on measurements made at one fixed site monitor per area. This may lead to exposure misclassification. The present paper validates a questionnaire-based indicator of ambient air pollution levels and its applicability to assess their within-area variability. Within the framework of the SAPALDIA (Swiss Study on Air Pollution and Lung Diseases in Adults) cross-sectional study (1991), 9,651 participants reported their level of annoyance caused by air pollution on an 11-point scale. This subjective measure was compared with annual mean concentrations of particulate matter less than 10 microm in diameter (PM10) and nitrogen dioxide. The impact of individual factors on reported scores was evaluated. Nitrogen dioxide concentrations at home outdoors (measured in 1993), smoking, workplace dust exposure, and respiratory symptoms were found to be predictors of individual annoyance scores. Regression of population mean annoyance scores against annual mean PM10 and nitrogen dioxide concentrations (measured in 1993 and 1991, respectively) across areas showed a linear relation and strong correlations (r>0.85). Analysis within areas yielded consistent results. The observed associations between subjective and objective air pollution exposure estimates suggest that population mean scores, but not individual scores, may serve as a simple tool for grading air quality within areas. Reported annoyance due to air pollution should be considered an indicator for a complex environmental condition and thus might be used for evaluating the implementation of environmental policies.

Adolescent↗

PubMed2001

Air pollution and emergency hospital admissions for cardiovascular diseases in Valencia, Spain.

STUDY OBJECTIVE: To estimate the short-term association between air pollution levels and emergency hospital admissions for cardiovascular diseases in Valencia, within 1994-1996 period. DESIGN: Daily levels of air pollution and emergency admissions for cardiovascular diseases were related to using an ecological time series design. The number of admissions was obtained from the hospital records database. Selected groups of causes were all cardiovascular diseases, heart admissions, and admissions for cerebrovascular diseases. The number of admissions for digestive diseases was used as control. Pollutants were black smoke, sulphur dioxide (SO(2)), nitrogen dioxide (NO(2)), carbon monoxide (CO) and ozone (O(3)). Magnitude of association was estimated by Poisson autoregressive regression. Estimations were calculated according the hottest (May to October) and the coldest (November to April) periods. SETTING: City of Valencia, Spain, about 750,000 inhabitants. PARTICIPANTS: People being admitted to the two major hospitals in the city, with a catchment area of nearly 400,000 inhabitants. MAIN RESULTS: For the whole period, a significant association for SO(2)-24 h was found so a rise in its levels of 10 microg/m(3) was associated with an increment of 3% (95%CI 0.4 to 5.7%) in the expected number of cardiovascular admissions. A significant association for black smoke, SO(2)-24 h, SO(2)-1 h, and CO-1 h was found in the hottest semester. All these associations were verified with a lag of two days. The estimates of the associations for particles, SO(2), and CO were affected by the inclusion of the other pollutants in their models. NO(2) was independently associated with cerebrovascular admissions. There were no significant associations between air pollution and admissions for digestive diseases. CONCLUSIONS: Current levels of air pollution and emergency cardiovascular admissions are significantly related in Valencia.

Air Pollutants↗

PubMed1997

Mechanisms of pollution-induced airway disease: in vivo studies.

Several studies have investigated the effects of ozone, sulphur dioxide (SO2), and nitrogen dioxide (NO2) on lung function in normal and asthmatic subjects. Decreased lung function has been observed with ozone levels as low as 0.15 ppm-this effect is concentration dependent and is exacerbated by exercise. A number of lines of evidence suggest that the effect on lung function is mediated, at least in part, by neural mechanisms. In both normals and asthmatics, ozone has been shown to induce neutrophilic inflammation, with increased levels of several inflammatory mediators, including prostaglandin E2. However, in normal subjects, none of the markers of inflammation correlate with changes in lung function. The lung function changes in asthmatics may be associated with inflammatory effects; alternatively, ozone may prime the airways for an increased response to subsequently inhaled allergen. Indeed, an influx of both polymorphonucleocytes and eosinophils has been observed in asthmatic patients after ozone exposure. It has been suggested that the effect of ozone on classic allergen-induced bronchoconstriction may be more significant than any direct effect of this pollutant in asthmatics. SO2 does not appear to affect lung function in normal subjects, but may induce bronchoconstriction in asthmatics. Nasal breathing, which is often impaired in asthmatics, reduces the pulmonary effects of SO2, since this water-soluble gas is absorbed by the nasal mucosa. NO2 may also influence lung function in asthmatics, but further research is warranted. SO2 and NO2 alone do not seem to have a priming effect in asthmatics, but a combination of these two gases has resulted in a heightened sensitivity to subsequently inhaled allergen.

Air Pollutants↗

PubMed1994

Chronic bronchitis, emphysema, and low-level air pollution in Helsinki, 1987-1989.

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.

Adult↗