There are many health issues associated with air pollution as well as a number of factors that have an effect on overall personal comfort and wellbeing.
Ozone (O3), nitrogen dioxide (NO2) and sulphur dioxide (SO2) all irritate the linings of the human respiratory system and can exacerbate chronic respiratory conditions such as asthma and bronchitis. Generally elderly people and young children are more susceptible to illnesses caused by poor air quality and increased hospital admissions regularly go hand-in-hand. During “episodes” of poor air quality, high levels of pollutants such as PM10 particles are thought to contribute to increased morbidity levels in high-risk patient groups.
Some VOCs (volatile organic compounds) such as Benzene and 1,3-Butadiene are known human carcinogens and mutagens along with other compounds such as vinyl chloride (used mainly in the manufacture of PVC).
Although many people are aware of the dangers of carbon monoxide (CO) in high concentrations (asphyxia), most are unaware of the problems caused by CO at lower levels - typically measured at the roadside. These can include lack of concentration, headache and general fatigue.
Carbon dioxide (CO2), although not considered a pollutant in ambient air (of course it is a major global warming gas), can reach very high levels inside, particularly in poorly ventilated offices where, either on its own or in combination with other factors such as temperature and humidity, it can lead to headaches, lack of concentration and other symptoms commonly associated with "sick building syndrome".
There are many other pollutants in ambient air to which we are all exposed. Some we know the possible health effects of, some we do not. Air quality monitoring is an evolving science and it may be many years before we are fully aware of the health implications caused by industrial, vehicular and domestic air pollution.