大气污染物与呼吸系统疾病急诊就诊关系的病例交叉研究

目的 分析大气污染急性暴露对呼吸系统疾病急诊人次的影响.方法 收集2004年1月1日至2005年12月31日北京大学第三医院急诊科呼吸系统疾病急诊资料和北京市环境监测中心大气污染物数据,应用时间分层的病例交叉设计研究方法进行数据分析,同时比较单向回顾性对照设计和双向对照设计研究结果的差异.结果 在调整气象因素并采用单向回顾性(多污染物)模型中,无滞后大气可吸入颗粒物(PM10)、二氧化硫(SO2)、滞后2 d二氧化氮(NO2)日平均浓度每增加10 μg/m3,呼吸系统疾病总急诊的OR值(95%CI)分别为1.010(1.005～1.014)、1.010(1.001～1.018)、0.996(0.983～1.009);双向对称性(多污染物)模型中,其相应OR值(95%CI)分别为1.002(0.998～1.005)、1.011(1.003～1.018)、1.012(1.001～1.022).采用不同对照选择方案,病例交叉设计的研究结果有变化.结论 区域内大气污染物暴露对居民呼吸系统疾病急诊人次有急性效应.     

气温变化与心脑血管疾病急诊关系的病例交叉研究

目的 探讨北京市日平均气温与心脑血管疾病急诊(ICD-10:I00～I99)的关系,研究气温变化对心脑血管疾病的影响.方法 收集北京大学第三医院急诊科心脑血管疾病急诊资料、北京市气象资料和北京市大气污染物数据,应用时间分层的病例交叉设计研究方法分析春季(3-5月)、夏季(6-8月)、秋季(9-11月)、冬季(12-2月)日平均气温与心脑血管疾病急诊的关系.结果 在控制二氧化硫(SO2)、二氧化氮(NO2)及大气可吸入颗粒物(PM10)影响的情况下,春季、夏季、秋季、冬季当日平均气温对心脑血管疾病急诊的影响最大,平均气温每升高1℃与心脑血管疾病急诊的OR值分别为1.282(95%CI:1.250 ～1.315)、1.027(95% CI:1.001～1.055)、0.661(95% CI:0.637～0.687)、0.960(95%CI:0.937～0.984),关联有统计学意义(P<0.05).当同时调整相对湿度、风速、大气压强的影响时,春季、夏季、秋季、冬季平均气温与心脑血管疾病急诊的OR值分别为1.423(95%CI:1.377～1.471)、1.082(95%CI:1.041～1.124)、0.633(95%CI:0.607～0.660)、0.971(95%CI:0.944～1.000).关联有统计学意义(P<0.05).结论 春季、夏季日平均气温升高可以导致心脑血管疾病急诊人次增加,说明春夏季气温升高对心脑血管疾病患者是危险因素,应注意防暑;秋季、冬季气温升高可以导致心脑血管疾病急诊减少,说明秋冬季气温升高对心脑血管疾病患者是保护性因素,应注意保暖.     

大气可吸入颗粒物与心脑血管疾病急诊关系的病例交叉研究

目的 探讨北京市大气可吸入颗粒物污染(PM10)对心腩血管疾病急诊的影响.方法 收集北京大学第三医院急诊科心脑血管疾病急诊资料和北京市环境监测中心大气污染物数据,应用时间分层的病例交叉设计研究方法进行数据分析.结果 无滞后单向同顾性1:4配对病例交叉研究的效应值(OR值)最大,在控制所选PM10当日气温、相对湿度影响的情况下,PM10浓度每提高10μg/m3与心脑血管疾病急诊(ICD-10:I00-I99)、冠心病急诊(ICD-10:120-125)、心律失常急诊(ICD-10:147-149)、心衰急诊(ICD-10:150)和脑血管疾病急诊(ICD-10:160-169)的OR值分别为1.006(95%CI:1.003～1.008)、1.003(95%CI:0.996～1.010)、1.005(95%CI:0.997～1.013)、1.019(95%CI:1.005～1.033)、1.003(95%CI:0.998～1.007),其中PM10与总心脑血管疾病急诊和心衰急诊的关联有统计学意义(P<0.05).结论 大气PM10污染物浓度升高可导致总心脑血管疾病急诊和心衰急诊增加.     

1,3-丁二烯作业工人的DNA修复能力

[目的]探讨DNA修复能力与1,3-丁二烯（BD）职业暴露致外周血淋巴细胞遗传学损伤的关联性。[方法]收集个人职业史、年龄、性别、吸烟和饮酒状况等信息,气相色谱法检测作业环境的BD浓度,利用染色体断裂试验评价60名职业BD暴露工人和60名非暴露工人的外周血淋巴细胞对诱变剂博莱霉素所致DNA损伤的修复能力。[结果]作业区空气中BD浓度为1.8（0.59~2.76）mg/m3。职业BD暴露组染色体断裂率[（1.06±0.41）%]高于对照组[（0.85±0.36）%,P〈0.01]。职业BD暴露人群中饮酒者的b/c值高于不饮酒者（P〈0.05）。[结论]DNA修复能力的下降可能是BD致癌过程中的重要生物学事件。     

Emergency room visits for respiratory conditions in children increased after Guagua Pichincha volcanic eruptions in April 2000 in Quito, Ecuador Observational Study: Time Series Analysis

Background

This study documented elevated rates of emergency room (ER) visits for acute upper and lower respiratory infections and asthma-related conditions in the children of Quito, Ecuador associated with the eruption of Guagua Pichincha in April of 2000.

Methods

We abstracted 5169 (43% females) ER records with primary respiratory conditions treated from January 1 – December 27, 2000 and examined the change in pediatric ER visits for respiratory conditions before, during, and after exposure events of April, 2000. We applied a Poisson regression model adapted to time series of cases for three non-overlapping disease categories: acute upper respiratory infection (AURI), acute lower respiratory infection (ALRI), and asthma-related conditions in boys and girls for three age groups: 0–4, 5–9, and 10–15 years.

Results

At the main pediatric medical facility, the Baca Ortiz Pediatric Hospital, the rate of emergency room (ER) visits due to respiratory conditions substantially increased in the three weeks after eruption (RR = 2.22, 95%CI = [1.95, 2.52] and RR = 1.72 95%CI = [1.49, 1.97] for lower and upper respiratory tract infections respectively. The largest impact of eruptions on respiratory distress was observed in children younger than 5 years (RR = 2.21, 95%CI = [1.79, 2.73] and RR = 2.16 95%CI = [1.67, 2.76] in boys and girls respectively). The rate of asthma and asthma-related diagnosis doubled during the period of volcano fumarolic activity (RR = 1.97, 95%CI = [1.19, 3.24]). Overall, 28 days of volcanic activity and ash releases resulted in 345 (95%CI = [241, 460]) additional ER visits due to respiratory conditions.

Conclusion

The study has demonstrated strong relationship between ash exposure and respiratory effects in children.     

石家庄市PM2.5浓度对居民死亡的急性影响分析

目的 了解石家庄市PM2.5污染特征及其对居民死亡率的影响。方法 收集2013 - 2015年该市逐日大气PM2.5浓度、平均气温、平均相对湿度和居民的死亡数据,利用广义相加模型分析PM2.5日均浓度和居民死亡的关系。结果 研究期间石家庄市日均非意外死亡32人,其中循环系统疾病死亡17人,呼吸系统疾病死亡5人;PM2.5浓度范围为6.3～771.3 μg/m3,平均浓度为118.8 μg/m3。时间序列分析结果表明,该市大气PM2.5浓度每升高10 μg/m3,居民非意外总死亡（lag05）、循环系统疾病死亡（lag05）和呼吸系统疾病死亡（lag1）的风险分别增加0.73%（95%CI:0.42%～1.04%）、1.04%（95%CI:0.64%～1.46%）和0.63%（95%CI:0.07%～1.19%）。结论 石家庄市大气PM2.5浓度的升高可能导致居民非意外总死亡,尤其是循环系统疾病和呼吸系统疾病死亡的增加。     

上海市大气污染对三级医院日医保急诊人次的影响

目的研究上海市大气污染水平与三级医院日医保急诊人次的关系。方法选用广义相加模型（generalized additive model,GAM）分析时间序列资料,并在模型中加入自回归模型AR（P）处理时间序列资料自相关的问题,在控制了与时间有关的中长期趋势、星期效应、节假日效应、非典事件、气象因素等混杂因素的基础上,分析了上海市2002--2004年间3种大气污染物PM10、SO2和NO2日均浓度变化与三级医院日医保急诊人次的关系。结果大气污染物PM10、SO2和NO2日均浓度每增加10μg／m^3,上海市三级医院医保急诊就诊的相对危险度分别为1．0017（95％CI1．0001～1．0034）,1．0066（95％CI1．0020～1．0111）和1．0052（95％CI1．0011-1．0094）。结论在上海市目前的大气污染水平下,所研究的3种污染物浓度水平对三级医院医保急诊人次有影响。     

上海市大气污染与某医院呼吸系统疾病门诊量关系的时间序列研究

[目的]探讨上海市大气污染物对人群呼吸系统疾病门诊量的短期影响。[方法]收集2010年1月1日—2012年10月31日上海市某三级甲等医院呼吸系统疾病每日门诊量统计资料和同期上海市大气及气象监测资料,采用时间序列的半参数广义相加模型,在控制了长期趋势、星期几效应、假期效应及气象因素等混杂因素的基础上,分析大气污染物与呼吸系统疾病日门诊量的关系。[结果]研究期间,呼吸系统疾病日门诊量为76~382人次。单污染模型中,二氧化硫（SO2）滞后4 d对呼吸系统疾病的影响最明显,二氧化氮（NO2）、可吸入颗粒物（PM10）滞后6 d的影响最明显;SO2、NO2、PM10浓度每增加10μg/m3,呼吸系统疾病日门诊量上升0.69%（RR=1.006 9,95%CI：1.003 5~1.010 3）、0.54%（RR=1.005 4,95%CI：1.002 8~1.007 9）和0.20%（RR=1.002 0,95%CI：1.001 1~1.002 8）。多污染模型中,调整其他污染物后,所有污染物健康效应估计值均较单污染模型降低,并不改变各污染物浓度与呼吸系统疾病日门诊量的正相关关系。[结论]大气污染物SO2、NO2、PM10与人群呼吸系统疾病门诊量存在正相关。     

北京市延庆区大气污染物对呼吸系统疾病门急诊量的影响

  目的  探讨北京市延庆区大气污染对人群呼吸系统疾病门急诊量影响。  方法  收集2014-2017年北京市延庆区二级医疗机构的呼吸系统疾病每日门急诊量数据和同期气象数据资料以及大气污染数据资料,运用时间序列的广义相加模型,在控制混杂因素的基础上,分析大气污染物浓度与呼吸系统门急诊量的关系以及滞后效应。  结果  研究表明,大气中空气动力学直径当量直径≤ 2.5 μm的颗粒物（particulate matter 2.5,PM_2.5）每增加10 μg/m3,呼吸系统门急诊量增加0.11%（RR=0.11,95%CI:0.09~0.14,P=0.001）;大气中空气动力学直径当量直径≤ 10 μm的颗粒物（particulate matter 10,PM₁₀）每增加10 μg/m3,呼吸系统门急诊量增加0.17%（RR=0.17,95%CI:0.15~0.19,P=0.001;二氧化氮（nitrogen dioxide,NO₂）每增加10 μg/m3,呼吸系统门急诊量增加0.44%（RR=0.44,95%CI:0.37~0.50,P=0.001）;一氧化碳（carbon monoxide,CO）每增加10 μg/m3,呼吸系统门急诊量增加3.34%（RR=3.34,95%CI:1.57~5.15,P=0.001）,且最强效应期均在第0 d。二氧化硫（sulfur ioxide,SO₂）每增加10 μg/m3呼吸系统门急诊量增加-1.69%（RR=-1.69,95%CI:-1.80~-1.57,P=0.001）,且在第1 d达到最强效应值。臭氧（ozone,O₃）每增加10 μg/m3呼吸系统门急诊量增加-0.12%（RR=0.12,95%CI:-0.15~-0.10,P=0.001）,且在第5 d达到最强效应值。双污染物模型分析中,CO在SO₂的影响下,对呼吸系统疾病门急诊人数影响尤为明显。  结论  本研究结果提示延庆区PM_2.5、PM₁₀、NO₂、CO浓度的增加均会导致呼吸系统门急诊量的增加,且不同污染物之间存在相互作用。     

银川市空气污染物与心脑血管疾病院前急救的关联性分析

目的 探讨银川市空气污染物与心脑血管疾病院前急救之间的关联。方法 收集2018年1月1日—2020年12月31日银川市人群心脑血管疾病院前急救资料、大气污染物(PM_2.5、PM₁₀、CO、SO₂、NO_x、O₃)和气象数据(平均温度、相对湿度),并作相关性分析。采用广义相加模型(GAM),在控制了星期几效应、气象因素后,研究大气污染物对心脑血管疾病发病的效应。结果 单污染物滞后模型结果显示PM₁₀在升高一个浓度单位后,在其滞后第五天心脑血管疾病的院前急救量增加,ER为0.056 6(95%CI:0.159 0～0.973 0);而O₃浓度在升高一个单位后,在其滞后的第三天和第六天使心脑血管疾病的院前急救量有所减少,其ER值分别为-0.101 0(95%CI:-0.195 2～-0.006 7),-0.114 1(95%CI:-0.207 9～-0.020 2)。在单污染物累积滞后模型中,O₃的累积效应呈负趋势,而N...     

大气PM10与心血管疾病就诊人次的时间序列分析

目的 研究大气PM10污染对居民心血管系统疾病日就诊人次的影响.方法 采用广义相加Poisson回归模型的时间序列分析,在控制长期趋势、星期几效应、气象因素等混杂因素的影响后,对2002年1月1日-2002年12月31日北京市大气PM10日均浓度与居民心血管系统疾病日就诊人次进行定量回归分析,并考虑滞后效应和其他空气污染物的影响.结果 大气PM10浓度每上升10μg/m~3,当天的心血管系统疾病日就诊人次增加O.380%(95%CI:0.326%～0.433%);滞后4 d PM10的健康效应最强,超额危险度为1.166%(95%CI:1.121%～1.212%);考虑CO、NO_2、SO_2:的影响均使PM10的健康效应估计值增高.结论 北京城区大气PM10污染与居民心血管系统疾病日就诊人次之间存在正相关.

Abstract：

Objective To estimate quantitatively the impact of the ambient PM10 on the hospital outpatients for cardiovascular diseases of local residents. Methods Time serial analysis using generalized addictive model (GAM) was applied. After controlling for those confounding factors such as long-term trend, weekly pattern and meteorological factors, considering lag effect and the influence of other air pollutants, excess relative risks (ER) of daily hospital visits associated with increasing PM10 level were estimated by fitting a Poisson regression model. Results A 10 μ.g/m~3 increase in PM10 levels was associated with an ER of 0.380% (95%CI: 0.326%～0.433%) for hospital visits for cardiovascular diseases. Lag effect of 4 days with an ER of 1.166% (95%C/:1.121%～1.212%) were observed. The ER value increased when CO, NO_2, SO_2 concentrations were introduced. Conclusion The ambient PM10 concentration is positively associated with daily hospital visits for cardiovascular diseases in Beijing.     

我国PM2.5污染与儿童呼吸系统疾病门诊量关系的Meta分析

目的 探究我国PM2.5污染与儿童呼吸系统疾病门诊量的暴露反应关系。方法 通过搜集并整理国内外数据库中2010—2020年发表的我国PM2.5浓度变化与儿童呼吸系统疾病门诊量的相关文献,运用Stata 11.0软件进行meta分析。结果 共纳入21篇文献,22组数据。我国PM2.5质量浓度每升高10 μg/m3,儿童呼吸系统疾病门诊量的相对危险度RR为1.003（95%CI:1.003,1.004）,发表偏倚校正后的RR为1.002（95%CI:1.002,1.003）。结论 我国PM2.5污染与儿童呼吸系统疾病的门诊量之间呈正相关。     

Differential susceptibility according to gender in the association between air pollution and mortality from respiratory diseases

This study analyzed the association between air pollution and deaths from respiratory diseases, considering differential susceptibility according to gender. The authors used daily deaths from respiratory diseases (ICD-10, J00-J99), PM(10), SO(2), and O(3) levels, and meteorological indicators in Volta Redonda, Rio de Janeiro State, Brazil, from January 2002 to December 2006. The association was estimated by Poisson regression using generalized additive models, where the increase in risk of deaths from PM(10) to lag 1 was 10.01% (95%CI: 1.81-18.88%) in the total female population and 10.04% (95%CI: 0.90-20.02%) in elderly women. The increase in risk of deaths from PM(10) to lag 9 was 8.25% in the total male population (95%CI: 0.86-16.18%) and 10.80% (95%CI: 2.18-20.15%) in elderly men. For exposure to SO(2) and O(3), the risk was significant in the total male population and the elderly, respectively. The results emphasize the need for further studies, focusing on modification of the effects of air pollution on health.     

合肥市大气PM2.5污染与居民呼吸系统疾病住院量的关系

目的 探讨合肥市大气PM2.5暴露对居民呼吸系统疾病住院量的影响。方法 收集合肥市2019年逐日大气污染物监测资料、气象资料及呼吸系统疾病住院资料。采用基于Poisson分布的GAM模型,评估PM2.5暴露对居民呼吸系统疾病住院量的影响。计算PM2.5浓度每升高10 μg/m3,居民呼吸系统疾病住院量增加的超额风险(ER)及95%可信区间（95%CI）。结果 合肥市大气PM2.5污染对居民呼吸系统疾病住院量存在显著影响。PM2.5每升高10 μg/m3,单日滞后效应和累积滞后效应分别在lag5和lag07时达到最大,居民呼吸系统疾病总住院量分别增加0.95% (95%CI:0.21% ~ 1.70%)和3.48% (95%CI:1.65% ~ 5.33%)。PM2.5对14岁及以下儿童的影响较其他年龄人群明显,对女性的影响也大于男性。结论 合肥市大气PM2.5浓度升高可能会增加居民呼吸系统疾病住院量,14岁及以下儿童及女性更敏感。     

Association between air pollution and ischemic cardiovascular emergency room visits

This study observed the relationship between air pollutants and ischemic cardiac diseases such as angina and acute myocardial infarction in a representative cardiovascular center emergency room in São Paulo, Brazil. Daily emergency room admissions to the Institute of the Heart of the University of São Paulo, as well as data concerning daily air pollutant levels and meteorological variables, were collected from January 1994 to August 1995. Generalized additive Poisson regressions were fitted to the logarithm of the expected values of total emergency room visits due to angina or acute myocardial infarction, controlling for smooth functions of season and weather and indicators for days of the week. All investigated pollutants were positively associated with ischemic cardiovascular disease emergency room visits, and the time lags were relatively short, but only CO presented an effect that was statistically significant. An interquartile range increase in CO was associated with an increase of 6.4% (95% CI: 0.7-12.1) in daily angina or acute myocardial infarction emergency room visits. This result did not change when estimates were done using linear models and natural cubic splines. This study showed that air pollution has a role in cardiovascular morbidity in São Paulo, reinforcing the necessity for air pollutant emission-controlling polices in urban areas.     

我国大气可吸入颗粒物污染对人群死亡率的影响

目的 综合相关文献并以暴露-反应关系的形式探讨中国可吸入颗粒物( PM10)污染对人群死亡率的影响.方法 收集符合纳入标准的中国大气颗粒物污染与居民总死亡率、心脑血管疾病死亡率、呼吸系统疾病死亡率关系的文献,共纳入21篇文献.采用Stata9.0软件进行统计分析,提取PM10与人群死亡率的暴露-反应系数,利用固定或随机效应模型合并效应值,并对结果进行敏感性分析、发表偏倚检验与校正.结果 我国大气PM10每上升10 μg/m3,人群每日总死亡率、心脑血管疾病和呼吸系统疾病死亡率的相对危险度(RR)分别为1.0033(95％ CI:1.0022～1.0044)、1.0045(95％ CI:1.0029 ～1.0062)和1.0056(95％CI:1.0033～1.0079);校正发表偏倚后,人群每日总死亡率、心脑血管疾病和呼吸系统疾病死亡率的RR值降为1.0012(95％CI:1.0002～1.0022)、1.0011(95％ CI:0.9996～1.0026)和1.0023(95％ CI:1.0001～1.0045).结论 大气中PM10浓度的上升会导致我国人群每日总死亡率、心脑血管疾病死亡率和呼吸系统疾病死亡率的增加.     

Population health effects of air quality changes due to forest fires in British Columbia in 2003: estimates from physician-visit billing data

BACKGROUND: Major forest fires near populated areas during 2003 exacted a huge economic toll on communities in British Columbia. We designed a study to examine associations between PM2.5 and PM10 levels and physician visits in two affected communities. METHODS: Measurements of 24-hour averages of particulate matter (PM10 and PM2.5) obtained from the monitoring network of the BC Ministry of Water, Land and Air Protection were used to define weeks where forest fires resulted in increases in ambient PM. Weekly rates of physician visits for respiratory (ICD-9 codes 460-519), cardiovascular (390-459) and mental illnesses (290-319) obtained through the Medical Services Plan of BC, were compared for 2003 and aggregates of the 10 previous years. RESULTS: Both the Kelowna and Kamloops regions experienced five weeks of elevated 24-hour average PM levels, although maximum levels in Kelowna were greater. In the Kelowna region, increases in physician visits for respiratory diseases of between 46 and 78% above 10-year mean rates were observed for three weeks during the forest fire period. Similar effects were not observed in Kamloops. Effects on visits for cardiovascular diseases or mental disorders were not seen in either community. INTERPRETATION: Forest fire smoke was associated with an excess of respiratory complaints in Kelowna area residents. The lack of a similar effect in Kamloops is likely due to the population being exposed to lower levels of PM. The absence of apparent cardiovascular health effects may be due to selective effects of forest fire smoke on respiratory tract disease.     

Effect of particulate matter air pollution on hospital admissions and medical visits for lung and heart disease in two southeast Idaho cities

Few, if any, published time series studies have evaluated the effects of particulate matter air exposures by combining hospital admissions with medical visit data for smaller populations. We investigated the relationship between daily particulate matter (<10 microm in aerometric diameter or PM10) exposures with admissions and medical visits (emergency room, urgent care, and family practice) for respiratory and cardiovascular disease in Pocatello and Chubbuck, Idaho (population about 60,000), from November 1994 through March 2000. Within generalized linear models, time, weather, influenza, and day-of-week effects were controlled. In single-pollutant models, respiratory disease admissions and visits increased (7.1-15.4% per 50 microg/m3 PM10) for each age group analyzed, with the highest increases in two groups, children and especially the elderly. Statistical analyses suggest that the results probably did not occur by chance. Sensitivity analyses did not provide strong evidence that the respiratory disease effect estimates were sensitive to reasonable changes in the final degrees of freedom choice for time and weather effects. No strong evidence of confounding by NO2 and SO2 was found from results of multi-pollutant models. Ozone and carbon monoxide data were not available to include multi-pollutant models, but evidence suggests that they were not a problem. Unexpectedly, evidence of an association between PM10 with cardiovascular disease was not found, possibly due to the lifestyles of the mostly Mormon study population. Successful time series analyses can be performed on smaller populations if diverse, centralized databases are available. Hospitals that offer urgent or other primary care services may be a rich source of data for researchers. Using data that potentially represented a wide-range of disease severity, the findings provide evidence that evaluating only hospital admissions or emergency room visit effects may underestimate the overall morbidity due to acute particulate matter exposures. Further work is planned to test this conclusion.     

2014-2017年沈阳市细颗粒物对居民循环系统疾病死亡的影响

目的 探讨沈阳市2014-2017年大气PM2.5污染与居民循环系统疾病死亡之间的关系.方法 分析沈阳市2014-2017年PM2.5污染特征、气象特征以及居民循环系统疾病死亡水平,采用广义线性模型分析大气PM2.5对居民循环系统疾病死亡的影响.结果 循环系统疾病死亡人数与气压、大气PM2.5、PM10、SO2和03-...     

Air pollution, aeroallergens and cardiorespiratory emergency department visits in Saint John, Canada

Existing studies of the association between air pollution, aeroallergens and emergency department (ED) visits have generally examined the effects of a few pollutants or aeroallergens on individual conditions such as asthma or chronic obstructive pulmonary disease. In this study, we considered a wide variety of respiratory and cardiac conditions and an extensive set of pollutants and aeroallergens, and utilized prospectively collected information on possible effect modifiers which would not normally be available from purely administrative data. The association between air pollution, aeroallergens and cardiorespiratory ED visits (n = 19,821) was examined for the period 1992 to 1996 using generalized additive models. ED visit, air pollution and aeroallergen time series were prefiltered using LOESS smoothers to minimize temporal confounding, and a parsimonious model was constructed to control for confounding by weather and day of week. Multipollutant and multi-aeroallergen models were constructed using stepwise procedures and sensitivity analyses were conducted by season, diagnosis, and selected individual characteristics or effect modifiers. In single-pollutant models, positive effects of all pollutants but NO2 and COH were observed on asthma visits, and positive effects on all respiratory diagnosis groups were observed for O3, SO2, PM10, PM2.5, and SO4(2-). Among cardiac conditions, only dysrhythmia visits were positively associated with all measures of particulate matter. In the final year-round multipollutant models, a 20.9% increase in cardiac ED visits was attributed to the combination of O3 (16.0%, 95% CI 2.8-30.9) and SO2 (4.9%, 95%CI 1.7-8.2) at the mean concentration of each pollutant. In the final multipollutant model for respiratory visits, O3 accounted for 3.9% of visits (95% CI 0.8-7.2), and SO2 for 3.7% (95% CI 1.5-6.0), whereas a weak, negative association was observed with NO2. In multi-aeroallergen models of warm season asthma ED visits, Ascomycetes, Alternaria and small round fungal spores accounted for 4.5% (95% CI 1.8-7.4), 4.7% (95% CI 1.0-8.6) and 3.0% (95% CI 0.8-5.1), respectively, of visits at their mean concentrations, and these effects were not sensitive to adjustment for air pollution effects. In conclusion, we observed a significant influence of the air pollution mix on cardiac and respiratory ED visits. Although in single-pollutant models, positive associations were noted between ED visits and some measures of particulate matter, in multipollutant models, pollutant gases, particularly ozone, exhibited more consistent effects. Aeroallergens were also significantly associated with warm season asthma ED visits.