Urban heat islands and an ever growing number of cars are just two environment phenomena that affect big cities and impair the health of the urban population.

Mortality and atmospheric pollution , Asthma and the environment , Heat waves , Car accidents and traffic-related injuries

• Mortality and atmospheric pollution
  According to Health Canada (2004), 1540 Montrealers die prematurely every year due to exposure to atmospheric pollution.  Of these cases, most (1140) are associated with long-term exposure.  Elderly people with cardiovascular and respiratory disease are particularly at risk.
  
  The risk of hospital admission for respiratory diseases is 30% higher among people aged 60 and over who live near roads with heavy traffic.
  
  
  
• Asthma and the environment
  The prevalence of asthma in the population of Montreal has been rising over the past 20 years.  In 2005, 9% of the population age 12 and over suffered from asthma.  For the 12-14 year age group, this figure nearly doubled (17.6%). The illness is more prevalent in certain areas of the Island, especially underprivileged neighbourhoods, where the prevalence of asthma and the number of emergency room visits and hospital admissions for the disease is higher than elsewhere.  Asthma is associated with poor interior and exterior air quality.  Although the problem has been growing, improved preventive and curative measures have resulted in a decrease of hospital admissions for pediatric asthma since 1996-1998.
  
  
  
• Heat waves
  Between 1984 and 2003, five week-long heat waves accounted for a increase in mortality of 60% or more. Climate change is expected to increase the number of heat waves in the future.  The risk of premature death from heat waves is higher for the elderly, for those who suffer from chronic illness and for those who live in a heat island or an underprivileged area.
  
  
  
• Car accidents and traffic-related injuries
  Death by car accident is most frequent in the young.  Car accidents cause 220 times more injuries than deaths in Montreal.  The number of Montrealers injured in car accidents went from 10,926 in 1998 to 12,803 in 2003, an increase of 17%. On average, five pedestrians are injured every day on the Island, and Montrealers account for nearly half of the number of pedestrian injuries throughout the province.  More injuries take place in central areas than do in outlying neighbourhoods.