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Table 2
Recent Studies of High Ambient Temperature and Mortality Examining Air Pollutants as Potential Confounders and/or Effect Modifiers
Reference	Study location	Method	Exposure	Causes of death	Result

Basu 2008 [6]	9 California counties, May to September 1999-2003	Time-series and case-crossover	Same day mean apparent temperature; daily mean O₃, also PM_2.5, PM₁₀, NO₂, CO, SO₂, lag 0 for PM, lag01 for gases	All-cause mortality	Confounders: none found Effect modifiers: none found

Bell 2008 [15]	Sao Paulo, Brazil, Santiago, Chile and Mexico City, Mexico, 1998-2002	Case-crossover	Same day apparent temperature compared with days at 75^thpercentile, same day lag O₃, same-day lag PM₁₀except Santiago lag 1 PM₁₀	All-cause daily mortality	Confounders: O₃, PM₁₀ Effect modifiers: not studied

McMichael 2008 [45]	Delhi, Monterrey, Mexico City, Chiang Mai, Bangkok, Salvador, Sao Paulo, Santiago, Cape Town, Ljubljana, Bucharest, Sofia, 2 to 5-year series (1991-1999)	Time-series	Daily maximum threshold (16°C-31°C) temperature, relative humidity, precipitation data, PM₁₀, BS, or TSP	All-cause mortality	Confounders: none found Effect modifiers: not studied

Ren 2008 [22]	US 95 NMMAPS counties, June to September 1987-2000	Time-series	Daily maximum temperature (same-day, lag 1), maximum hourly O₃	CVD mortality	Confounders: not studied Effect modifier: O₃

Vaneckova 2008a [46]	Sydney, Australia, October to March 1993-2001	Time-series	Temporal Synoptic Index (TSI) on the highest 10% mortality days, O₃, PM₁₀	All-cause, circulatory, cerebrovascular	Confounders: O₃on warm, humid days and PM₁₀on hot, dry days Effect modifiers: not studied

Vaneckova 2008b [19]	Sydney, Australia, October to March 1993-2004	Time-series	Daily maximum temperature, maximum O₃	Underlying and associated causes of death	Confounders: O₃, PM₁₀ Effect modifiers: not studied

Zanobetti and Schwartz 2008 [7]	9 U.S. counties, May to September 1999-2002	Time series and case-crossover	Daily apparent temperature (minimum, mean, maximum); daily mean O₃, PM_2.5	All-cause mortality	Confounders: none found Effect modifiers: none found

Kolb 2007 [32]	Montreal, Canada 1984-1993	Case-crossover	Mean daily and maximum temperature, barometric pressure, relative humidity, adjusted for O₃and both NO₂and O₃	Daily all-cause mortality	Confounders: none found Effect modifiers: not studied

Medina-Ramon 2007 [21]	50 US cities in cold (November to March) and warm (May to September) seasons	Case-crossover	Binary variable as extreme temperature and continuous; O₃	All-cause and CVD mortality	Confounder: O₃ Effect modifiers: not studied

Filleul 2006 [23]	9 French cities, all year and heat wave August 2003	Time-series	Minimum and maximum temperature, 8-hour maximum O₃	Daily all-cause mortality	Confounders: not studied Effect modifier: O₃for some cities

Ren 2006 [51]	Brisbane, Australia (all year January 1996 to December 2001)	Time-series	Minimum temperature, daily PM₁₀as modifier	Cardiorespiratory mortality	Confounders: not studied Effect modifier: PM₁₀

Stafoggia 2006 [16]	Bologna, Milan, Rome, Turin, 1997-2003	Case-crossover	30°C mean apparent temperature (lag01) relative to 20°C, O₃	All-cause mortality	Confounders: none found Effect modifiers: not studied

Basu 2005 [5]	20 US metropolitan areas, seasonal analysis 1992	Time series (and case-crossover	Mean daily temperature per 10°F adjusted for dew point temperature; daily O₃	Individual and daily cardiorespiratory mortality	Confounders: PM₁₀in summer Effect modifiers: not studied

O'Neill 2005 [18]	Mexico City (1996-98) and Monterrey (1996-99)	Time series; % change	Heat (35-36°C for Monterrey), mean temperature (25°C Monterrey, 15°C Mexico City), daily O₃	Daily all-cause mortality	Confounders: O₃and PM₁₀on hot days Effect modifiers: not studied

Rainham and Smoyer-Tomic 2003 [17]	Toronto, May 1 to September 30, 1980-1996	Time-series; relative risk (RR)	Humidex, O₃, also CO, NO₂, SO₂	Daily all-cause mortality	Confounders: none found Effect modifiers: not studied

Pattenden 2003 [49]	Sofia, Bulgaria (1996-1999) and London, England (1993-1996)	Time-series; % change	Daily weather (2-day mean) and PM (black smoke for London and total suspended particulates for Sofia)	Daily all-cause mortality	Confounders: none found Effect modifiers: not studied

Basu Environmental Health 2009 8:40 doi:10.1186/1476-069X-8-40

Table 2