Commentary

In the Russian classic Anna Karenina, Leo Tolstoy wrote that, while “All happy families are alike; each unhappy family is unhappy in its own way.” Similarly, it can seem that recent catastrophic heat waves—such as those in Chicago in 1995, France in 2003, and Russia in 2010—have each been catastrophic in its own unique way. The Chicago 1995 heat wave, which caused about 700 excess deaths in a week, was accompanied by a major power outage that left 49,000 homes without power and therefore without air conditioning, fans, refrigerators, or (for upper-level apartments) elevator access or water.1 The 2003 European heat wave was associated with 15,000 excess deaths in France.2 Some have suggested that this number was extraordinarily high because of the French tradition of lengthy August holidays and the 35-hour work week,3 both of which limited the number of medical professionals and family members available to respond to those endangered by the heat. The 2010 Russian heat wave has its own defining characteristic—it was accompanied by record-breaking forest fires that blanketed western Russia in haze.4 The underground peat that is characteristic of the area allowed fires to spread underground past fire breaks, making the fires hard to put out or control.5 Air pollution from these fires was also record-breaking,5 exposing Muscovites to dangerous concentrations of ozone and particulate matter6 and reducing visibility so severely that planes were grounded.7,8 The temperatures themselves were also unprecedented, sometimes climbing four standard deviations above normal.9 On the basis of preliminary estimates of 55,000 excess deaths in Russia, the Center for Research on the Epidemiology of Disasters declared this heat wave one of two “mega-disasters” worldwide in 2010, together with the Haitian earthquake.10 In this issue of EPIDEMIOLOGY, Shaposhnikov and coauthors11 incorporate newly available health data to update earlier mortality estimates for this heat wave. In particular, the authors focus on the interaction of heat with the wildfire-related air pollution that helped define this particular heat wave. However, while the heat wave unquestionably produced memorable images of a sweltering Moscow, with haze so thick the Kremlin was barely visible across Red Square,12 some notable features of this heat wave are not dissimilar from other catastrophic heat waves. In fact, a review of recent heat waves suggests that, unlike Tolstoy’s unhappy families, catastrophic heat waves are often catastrophic in very similar ways, which are listed below. PEOPLE ARE OUT-OF-TOWN Heat waves occur during the summer, when city leaders and health workers are often away. The most famous example is the 2003 French heat wave. Only 80% of general practitioners, for example, were working during this heat wave.13 Many government leaders were also away from their Paris offices: the prime minister was in the Alps,14 the minister of health in the Riviera,3,14 and the president in Canada (where he remained until after the heat wave ended).3 While this example resonates, given the well-known French tradition of August vacations, the trend repeats for other heat waves. Mayor Daley was away during the 1995 Chicago heat wave, as were the city’s health and fire commissioners.1 During the 2010 Russian heat wave, President Dmitri Medvedev had to return from vacation in Sochi.5,7 When government leaders are away, they are limited in their ability to assess the severity of the event and are hindered in deploying an adequate response. These problems can delay the declaration of a state of emergency, as happened in Chicago in 19951 and France in 2003.15 INFRASTRUCTURE TAKES A HIT Although we do not think of heat waves as causing the physical damage of hurricanes, floods, or earthquakes, they can still damage and impair infrastructure. Extreme heat waves often cause power outages, which increase heat exposure in air-conditioned homes and cause numerous problems in dense urban areas, where high-rise buildings lose water and elevator access. During the 1995 Chicago heat wave, Mayor Daley and other city officials accused the power company Commonwealth Edison as being a major contributor to the city’s high death count.1 This outage was not unique—major power outages have accompanied various other heat waves, including those in 2006 in Queens, NY,16 in 2009 in Australia,17 and in 2006 in Wisconsin and Michigan.18 During a heat wave, power grids are strained in particular by high air-conditioning use. Heat waves are often accompanied by severe summer storms that down power lines, like the “derecho” storms in 2012 in the eastern United States.19 Nuclear power plants sometimes must shut down over concerns about the temperature of cooling water, as in Germany in 2003.20 Transportation and water supply can also be affected. Heat can melt road asphalt (eg, Australia in 2013,21 Europe in 2003,20 Russia in 201022) and threaten to buckle the metal in drawbridges and railroad tracks (eg, Chicago in 1995,1 Australia in 2009,17 France in 200315). Water pressure dropped in much of Chicago in 2003 when people opened fire hydrants to cool off, and power outages can keep water from reaching higher apartments.1 SUPPLIES RUN OUT AND SERVICES ARE OVERWHELMED In Russia in 2010, morgues were so overwhelmed that one health official asked families to consider burying dead relatives earlier than 3 days after death, the Russian Orthodox standard.8 Emergency responders,15 emergency rooms,14 and hospitals15 were overwhelmed in France in 2003, while in Chicago in 1995, ambulance response times increased substantially and over 20 hospitals had to go on bypass, refusing to accept new patients at some point during the heat wave.1 Many excess deaths during a heat wave are from cardiovascular causes,23 for which response time is a key determinant of whether a victim survives the initial attack.24 In addition to medical services being overwhelmed, supplies such as air-conditioning units and fans sell out (eg, Russia in 2010,8 Chicago in 200525). During the 2010 Russian heat wave, train and plane tickets to cooler places sold out,8 as did affordable air-conditioned hotel rooms in Moscow.8 These shortages impair residents’ abilities to “beat the heat” on their own. AIR POLLUTION AND FOREST FIRES ARE OFTEN ACCOMPANYING DANGERS As discussed by Shaposhnikov and coauthors,11 the 2010 heat wave was memorably accompanied by severe forest fires and air pollution. While this case was extreme, neither severe air pollution nor forest fires are unique to this heat wave. High levels of air pollution characterized heat waves in France in 2003, Athens in 1987, Belgium in 1994, and England in 1995.2,15 Forest fires accompanied heat waves in Russia in 20026; in Spain, Portugal, and France in 200315,20; in New South Wales in 201321; and in 2012 in Colorado, Wyoming, and Utah.19 The formation of secondary air pollutants can speed up with high temperatures, and low wind speeds prevent pollution from dispersing, which allows pollution to accumulate to dangerous levels.4,6 Forest fires can aggravate already high pollution levels (as in Russia in 2010) by increasing atmospheric concentrations of primary particulate matter as well as precursors of ozone and other secondary pollutants.6 The combination of heat and air pollution, as Shaposhnikov and coauthors11 highlight, can be extremely dangerous to human health. These four complications emerge repeatedly during severe heat waves and are factors for health officials to consider when crafting heat response plans. Heat response plans are not, however, sufficient during a catastrophic heat wave. Severe health effects like those of the 1995, 2003, and 2010 heat waves can have a very fast onset that requires rapid identification and response from public health officials. Unfortunately, a further trend in catastrophic heat waves is that excess death counts are often a source of controversy during the event. Death certificates take time to process and convert to statistical summaries, which means that often the first officials to notice severe heat-related health impacts are those who care for the dead—medical examiners, morgues, and funeral services. For example, in 2003, the extraordinary increase in deaths in France was first noticed by the country’s largest funeral service, the Pompes Funèbres Générales.15 However, these initial alarms from local health officials are often disputed by higher level officials, as they were in Philadelphia in 199326 and in Chicago in 1995.1 In 2003, Italy’s initial estimate of excess deaths was below half the final count of 20,000.27 In Russia in 2010, there was reportedly political pressure to avoid mentioning heat in medical reports.5,12 Often, these disagreements are settled only long after the heat wave is over—well after anything can be done to prevent further deaths. According to reports, responses to extreme heat were delayed in Chicago in 19951,26 and in France in 200315 because the degree of social and health impact caught leaders by surprise. There is little to suggest that similarly catastrophic heat waves might not hit next summer in Cape Town or Tokyo or Rio de Janeiro or New York City. The analysis of Shaposhnikov and coauthors11 on the Russian 2010 heat wave is a reminder that a severe heat wave can present an extraordinary public health threat, especially when combined with the conditions (high air pollution, infrastructure damage, shortage of supplies, out-of-town officials) that so often make catastrophic heat waves alike. ABOUT THE AUTHOR G. BROOKE ANDERSON is a Postdoctoral Fellow at Johns Hopkins Bloomberg School of Public Health’s Department of Biostatistics. Her research focuses on the health effects of extreme weather and air pollution.

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