Nitrogen dioxide is mainly generated by vehicle emissions. It indicates the presence of other oxides of nitrogen (collectively described as NOX). Colors and column heights show the distribution of annual average emissions of NO2 in central London.

The presence of oxides of nitrogen (NOX) is highly linked to No2 concentration. Colors and column heights show the distribution of annual average emissions of NOX in central London.

Heavier particulate matter such as smoke, dust from roads and construction sites, most harmful when breathed into deepest part of lungs. Primary effect on health is damage to lungs, heart and circulation.Colors and column heights show the distribution of annual average emissions of PM10 in central London.

Colors and column heights show the distribution of the volume of PM10 exceeding the EU emission limit.

Fine particulate matter (PM2.5) sources include burning and vehicle emissions. It is light and remains suspended in the air for a long time (it is the main visible component of pollution), causing coughing, sneezing and shortness of breath. Long term effects include asthma, chronic bronchitis and heart disease. Colors and column heights show the distribution of the volume of PM2.5 exceeding the EU emission limit.