Even at levels lower than those considered safe by United States regulators, exposure to three components of<unk> , fine particulate matter, nitrogen dioxide and ozone, correlates with cardiac and respiratory illness. In 2020, pollution (including<unk>  was a contributing factor to one in eight deaths in Europe, and was a significant risk factor for pollution-related diseases including heart disease, stroke and lung cancer. The health effects caused by<unk>  may include difficulty in breathing, wheezing, coughing, asthma and worsening of existing respiratory and cardiac conditions. These effects can result in increased medication use, increased doctor or emergency department visits, more hospital admissions and premature death. The human health effects of poor<unk>  quality are far reaching, but principally affect the body's respiratory system and the cardiovascular system. Individual reactions to<unk>  pollutants depend on the type of pollutant a person is exposed to, the degree of exposure, and the individual's health status and genetics. The most common sources of<unk>  include particulates, ozone, nitrogen dioxide, and sulfur dioxide. Children aged less than five years who live in developing countries are the most vulnerable population in terms of total deaths attributable to indoor and outdoor<unk> . Mortality upright=1.5 Share of deaths from outdoor<unk> , OWID The World Health Organization estimated in 2014 that every year<unk>  causes the premature death of some 7 million people worldwide. Studies published in March 2019 indicated that the number may be around 8.8 million. Causes of deaths include strokes, heart disease, COPD, lung cancer, and lung infections. Urban outdoor<unk>  is estimated to cause 1.3 million deaths worldwide per year. Children are particularly at risk due to the immaturity of their respiratory organ systems. In 2015, outdoor<unk> , mostly by PM2.5, was estimated to lead to 3.3 (95% CI 1.61–4.81) million premature deaths per year worldwide, predominantly in Asia. In 2021, the WHO reported that outdoor<unk>  was estimated to cause 4.2 million premature deaths worldwide in 2016. A 2020 study indicates that the global mean loss of life expectancy (LLE) from<unk>  in 2015 was 2.9 years, substantially more than, for example, 0.3 years from all forms of direct violence, albeit a significant fraction of the LLE is unavoidable. Moreover, communities with the most exceptional aging have low ambient<unk> , suggesting a link between<unk>  levels and longevity. By region India and China have the highest death rate due to<unk> . India also has more deaths from asthma than any other nation according to the World Health Organization. In December 2013<unk>  was estimated to kill 500,000 people in China each year. There is a positive correlation between pneumonia-related deaths and<unk>  from motor vehicle emissions. Annual premature European deaths caused by<unk>  are estimated at 430,000 to 800,000. An important cause of these deaths is nitrogen dioxide and other nitrogen oxides (NOx) emitted by road vehicles. In a 2015 consultation document the UK government disclosed that nitrogen dioxide is responsible for 23,500 premature UK deaths per annum. Across the European Union,<unk>  is estimated to reduce life expectancy by almost nine months. Guidelines The US EPA has estimated that limiting ground-level ozone concentration to 65 parts per billion (ppb), would avert 1,700 to 5,100 premature deaths nationwide in 2020 compared with the 75 ppb standard. The agency projected the more protective standard would also prevent an additional 26,000 cases of aggravated asthma, and more than a million cases of missed work or school. Following this assessment, the EPA acted to protect public health by lowering the National Ambient<unk>  Quality Standards (NAAQS) for ground-level ozone to 70 ppb. A new economic study of the health impacts and associated costs of<unk>  in the Los Angeles Basin and San Joaquin Valley of Southern California shows that more than 3,800 people die prematurely (approximately 14 years earlier than normal) each year because<unk>  levels violate federal standards. The number of annual premature deaths is considerably higher than the fatalities related to auto collisions in the same area, which average fewer than 2,000 per year. A 2021 study found that outdoor<unk>  is associated with substantially increased mortality "even at low pollution levels below the current European and North American standards and WHO guideline values" shortly before the WHO adjusted its guidelines. Major causes Comparison of footprint-based and transboundary pollution-based relationships among G20 nations for the number of PM2.5-related premature deaths. The largest cause is<unk>  generated by fossil fuel combustion – mostly the production and use of cars, electricity production and heating. A study by Greenpeace estimates there are 4.5 million annual premature deaths worldwide because of pollutants released by high-emission power stations and vehicle exhausts. Diesel exhaust (DE) is a major contributor to combustion-derived particulate matter<unk> . In several human experimental studies, using a well-validated exposure chamber setup, DE has been linked to acute vascular dysfunction and increased thrombus formation. A study concluded that PM2.5<unk>  induced by the contemporary free trade and consumption by the G20 nations causes two million premature deaths annually, suggesting that the average lifetime consumption of about ~28 people in these countries causes at least one premature death (average age ~67) while developing countries "cannot be expected" to implement or be able to implement countermeasures without external support or internationally coordinated efforts. Primary mechanisms The WHO estimates that in 2016, ~58% of outdoor<unk> -related premature deaths were due to ischaemic heart disease and stroke. The mechanisms linking<unk>  to increased cardiovascular mortality are uncertain, but probably include pulmonary and systemic inflammation. Contemporary annual deaths A study by scientists of U.K. and U.S. universities that uses a high spatial resolution model and an updated concentration-response function concluded in 2021 that 10.4 million global excess deaths in 2012 and 8.7 million in 2018 – or – were due to<unk>  generated by fossil fuel combustion, significantly higher than earlier estimates and with spatially subdivided mortality impacts. According to the WHO<unk>  accounts for 1 in 8 deaths worldwide. Cardiovascular disease A 2007 review of evidence found that, ambient<unk>  exposure is a risk factor correlating with increased total mortality from cardiovascular events (range: 12% to 14% per 10 µg/m3 increase).<unk>  is also emerging as a risk factor for stroke, particularly in developing countries where pollutant levels are highest. A 2007 study found that in women,<unk>  is not associated with hemorrhagic but with ischemic stroke.<unk>  was also found to be associated with increased incidence and mortality from coronary stroke in a cohort study in 2011. Associations are believed to be causal and effects may be mediated by vasoconstriction, low-grade inflammation and atherosclerosis. Other mechanisms such as autonomic nervous system imbalance have also been suggested. Lung disease Research has demonstrated increased risk of developing asthma and chronic obstructive pulmonary disease (COPD) from increased exposure to traffic-related<unk> . Additionally,<unk>  has been associated with increased hospitalization and mortality from asthma and COPD. COPD includes diseases such as chronic bronchitis and emphysema. A study conducted in 1960–1961 in the wake of the Great Smog of 1952 compared 293 London residents with 477 residents of Gloucester, Peterborough, and Norwich, three towns with low reported death rates from chronic bronchitis. All subjects were male postal truck drivers aged 40 to 59. Compared to the subjects from the outlying towns, the London subjects exhibited more severe respiratory symptoms (including cough, phlegm, and dyspnea), reduced lung function (FEV1 and peak flow rate), and increased sputum production and purulence. The differences were more pronounced for subjects aged 50 to 59. The study controlled for age and smoking habits, so concluded that<unk>  was the most likely cause of the observed differences. More studies have shown that<unk>  exposure from traffic reduces lung function development in children and lung function may be compromised by<unk>  even at low concentrations. It is believed that much like cystic fibrosis, by living in a more urban environment serious health hazards become more apparent. Studies have shown that in urban areas people suffer mucus hypersecretion, lower levels of lung function, and more self-diagnosis of chronic bronchitis and emphysema. Cancer (lung cancer) Unprotected exposure to PM2.5<unk>  can be equivalent to smoking multiple cigarettes per day, potentially increasing the risk of cancer, which is mainly the result of environmental factors.|alt A review of evidence regarding whether ambient<unk>  exposure is a risk factor for cancer in 2007 found solid data to conclude that long-term exposure to PM2.5 (fine particulates) increases the overall risk of non-accidental mortality by 6% per a 10 microg/m3 increase. Exposure to PM2.5 was also associated with an increased risk of mortality from lung cancer (range: 15% to 21% per 10 microg/m3 increase) and total cardiovascular mortality (range: 12% to 14% per a 10 microg/m3 increase). The review further noted that living close to busy traffic appears to be associated with
Air pollution
Noise pollution
Drug pollution
Toxic waste
Cigarette Burns
Tobacco smoke
Third-hand smoke
Work accident