Air Pollution (Point Source)

Primary reference(s)

Dunne, A., L. Mitchem, J. Wilding and A. Kibble, 2014. Air pollution and public health. In: Bradley, N., H. Harrison, G. Hodgson, R. Kamanyire, A. Kibble and V. Murray (eds.), Essentials of Environmental Public Health Science: A Handbook for Field Professionals. Chapter 4. Oxford University Press. Accessed 3 November 2020.

Kibble, A. and R. Harrison, 2005. Point sources of air pollution. Occupational Medicine, 55:425-431.

Additional scientific description

Point source air pollution can be natural or man-made. A human generated point source of air pollution is one that emits a significant amount of an air pollutant from a fixed location such as an explosion, pollutants from a chimney stack or a tyre fire. Examples of point sources include power stations, steel works, foundries, incinerators, wood and pulp processors, paper mills, refineries and chemical production (Kibble and Harrison, 2005; Dunne et al., 2014). Point sources of air pollution from naturally occurring sources include smoke from wildfires, ash from volcanic eruptions and sand particles from deserts lifted and transported in the wind across cities and continents.

Many people, particularly those in poorer populations or with pre-existing vulnerabilities, live near point sources of air pollution such as industrial sites and waste disposal operations. Point sources frequently generate speculation regarding potential association with disease clusters such as cancer, among those living in close proximity to the source location. Suspected disease clusters tend to generate significant public concern and media interest. However, there are currently limited epidemiological methods to enable effective detailed investigations into the impact of point-source air pollution and causal links with the disease of interest in identified clusters. There is a particular challenge with respect to obtaining reliable and accurate population exposure data at a very local level (WHO, no date).

In many cases, the key question is whether releases from a point source result in a significant increase in exposure or whether other sources (background exposure) give rise to the dominant exposure (Kibble and Harrison, 2005). Detailed investigation of these differences requires high spatio-temporal resolution air quality data alongside incidence data obtained from accurate health information systems, such as disease registers or via case control studies.

Metrics and numeric limits

World Health Organization (WHO) Air quality guidelines for particulate matter, ozone, nitrogen dioxide and sulphur dioxide (WHO, 2006).

Examples of drivers, outcomes and risk management

+Point source air pollution focuses on acute and chronic sources of such pollution. The WHO considers that all sources of air pollution contribute to early deaths; included in this are the combined effects of ambient (outdoor) and household air pollution which cause approximately seven million premature deaths every year, largely as a result of increased mortality from stroke, heart disease, chronic obstructive pulmonary disease, lung cancer and acute respiratory infections (Health Effects Institute, 2020; WHO, 2020a).

Sources of air pollution are multiple and context-specific. The major ambient pollution sources include biomass fuel combustion for domestic cooking and heating, vehicles, power generation, agriculture/waste incineration, and industry. Policies and investments supporting integrated policies that support sustainable land use, cleaner household energy and transport, energy-efficient housing, power generation, industry, and better municipal waste management can effectively reduce key sources of ambient air pollution (WHO, 2020a).

Incidents such as wildfires and volcanic eruptions can also impact on air quality. For example, research shows that wildfires can cause a large increase in gaseous air pollutants such as carbon monoxide, nitrogen dioxide, acetaldehyde and formaldehyde (Finlay et al., 2012).

Adverse health consequences of air pollution can occur as a result of short- or long-term exposure. The pollutants with the strongest evidence of health effects are particulate matter, ozone, nitrogen dioxide and sulphur dioxide (WHO, 2020b).

Although most emissions of point source air pollution are from local or regional sources, under certain atmospheric conditions air pollution can travel long distances across national borders over time scales of four to six days, thereby affecting people far from its original source. For example, windblown dust from desert regions of Africa, Mongolia, Central Asia and China can carry large concentrations of particulate matter, and fungal spores and bacteria that impact health and air quality in remote areas. Therefore, global cooperation is needed to address international flows and sources of air pollutants, complementary to local and regional efforts in air pollution management (WHO, 2020b).