PM10s PM5s Particulates

NO NO2 Oxides of nitrogen

SO2 Sulphur Dioxide

O3 Ozone

CxHx Hydrocarbons

VOCs Volatile Organic Compounds

CO Carbon Monoxide

C6H6 Benzene

Pb Lead

If Terminal 5 is given the go ahead, pollution will increase in an already badly affected area with consequences for the people's health especially pregnant women, the very young, elderly and people with breathing difficulties. This page explains just what is served up in the chemical cocktail from roads which will be under pressure to be widened if T5 is built.

SULPHUR DIOXIDE aggravates breathing problems by tightening the tubes carrying air to the lungs. People with cardio-respiratory disease are particularly vulnerable. Levels are boosted by fumes from diesel and other vehicles.

NITROGEN OXIDES: Nitrogen dioxide gas can aggravate asthma, cause eye and throat irritation and may also reduce the body's resistance to infection. In the UK, motor vehicles are the main source. Aircraft produce high amounts of Nitrogen oxides when they take off.

CARBON MONOXIDE reduces the amount of oxygen being carried by the blood and at high levels can cause headaches and drowsiness and even death. Road transport is responsible for 90% of carbon monoxide into the air.

HYDROCARBONS: either gases (VOC's) or solids (particulates).

Volatile Organic Compounds (VOC's) are smog-forming gases, and include benzene. Benzene escapes from exhausts and petrol tanks and is a carcinogen (can cause cancer), for which the World Health Organisation says there is no safe level.

Particulates are tiny sooty dust particles responsible for most of the smell and dirt associated with traffic pollution. The smaller particles, known as PM10's (because they measure less than 10 micrometres), can pass deep into our lungs and are thought to be responsible for 10,000 deaths a year in the UK. Motor vehicles, largely diesels, are responsible for 90% of the smaller particulates in London's air.

OZONE in the upper atmosphere protects us from the Sun's ultra violet rays but at ground level, it can cause serious harm to our lungs and immune systems. In smaller amounts it can irritate our throat and lungs, causing coughing and pain on deep breathing.

Ground level ozone is a major constituent of photochemical smogs which form when other pollutants such as nitrogen oxides and hydrocarbons, react with sunlight. 37% of VOC emissions which lead to the formation of ground-level ozone are produced by motor vehicles. At Heathrow, aircraft contribute to the problem of ground level ozone and smogs.

Heathrow Terminal 5