titre:Air pollu-
tion ---- color: #00BCE4 ---- id: airpollution ---- imagehead: 20_Taxus_baccata.jpg ---- imagestart: dust-nb.jpg ---- imageend: ---- text: ## Air pollutants There are several key air pollutants that this toolkit addresses. These pollutants have significant negative effects on health and environments. Many pollutants such as particulate matter 2.5 and nitrogen dioxide can impact cardiovascular and pulmonary health, causing asthma, strokes, heart attacks and other cardiovascular diseases. The Royal College of Physicians has estimated that approximately 40,000 air pollution related deaths occur in the UK every year. Air pollution is now considered to be a leading cause of death worldwide, with the World Health Organisation (WHO) estimating that 7 million deaths per year are attributable to air pollution. Air pollution is an environmental public health problem. Pollutants have negative consequences for human health, and pollutants can also damage plants and ecosystems. Some plants can play a role in mitigating and phyto-remediating pollutants, and well planted gardens on tree-lined pedestrian streets can have significantly lower levels of pollution than busy traffic intersections. However, it is always best to reduce or eliminate pollution at the source, and to develop air quality gardens as a complementary strategy for improving urban environments. **For information on air quality, see:** European Commission, “Air Quality Standards”, http://ec.europa.eu/environment/air/quality/standards.htm. Royal College of Physicians, “Every breath we take: the lifelong impact of air pollution” (23 February 2016), https://www.rcplondon.ac.uk/projects/outputs/every-breath-we-take-lifelong-impact-air-pollution. World Health Organisation (WHO), “7 million premature deaths annually linked to air pollution” (25 March 2014), http://www.who.int/mediacentre/news/releases/2014/air-pollution/en. ## Particulate matter Particulate matter 2.5 and 10 (PM2.5 and PM10) are criteria air pollutants that are a mixture of dust, sand, soot, and smoke. PM10 is 10 micrometers or smaller, and PM2.5 is 2.5 micrometers or smaller. PM2.5 is particularly haz-ardous to human health, as it can enter the lungs and bloodstream. ## Heavy metals There are a number of heavy metal pollutants in the air and soil, including lead, cadmium, arsenic and nickel. Plants at times take up heavy metals in a process of phyto-remediation. At other times, plants can be damaged and their growth slowed by heavy metal pollution. ## Nitrogen dioxide Nitrogen dioxide (NO2) is a reactive gas that forms through the burning of fuel, whether from transport or heating. NO2 can cause respiratory damage and aggravate existing conditions such as asthma. NO2 can also con- tribute to acid rain, hazy air and nutrient pollution in water. ## Sulphur dioxide Sulphur dioxide (SO2) most often forms through the burning of coal, as well as other industrial processes. SO2 levels have declined from the time of ‘pea soup’ fogs in post-war London, but pollutants such as NO2 and PM2.5 have risen. SO2 can contribute to respiratory problems, as well as acid rain and vegetation damage. ## Ozone Ground-level ozone (O3) is formed through the interaction of nitrogen oxides (NOx) and volatile organic compounds (VOCs). Ozone can contribute to respiratory problems, and it also can damage vegetation and ecosys- tems that are sensitive to this pollutant.