Outdoor Air Pollution: A Global Environmental Health Problem

Outdoor air pollution is a major environmental health problem that affects people in low-, middle-, and high-income countries. According to the World Health Organization (WHO), ambient (outdoor) air pollution in both cities and rural areas was estimated to cause 4.2 million premature deaths worldwide per year in 2019. This mortality is due to exposure to fine particulate matter, which causes cardiovascular and respiratory disease, and cancers.

Air Pollution and its Impact on Health

• WHO estimates that in 2019, some 37% of outdoor air pollution-related premature deaths were due to ischemic heart disease and stroke, 18% and 23% of deaths were due to chronic obstructive pulmonary disease and acute lower respiratory infections respectively, and 11% of deaths were due to cancer within the respiratory tract.
• People living in low- and middle-income countries disproportionately experience the burden of outdoor air pollution with 89% (of the 4.2 million premature deaths) occurring in these areas. The greatest burden is found in the WHO South-East Asia and Western Pacific regions. The latest burden estimates reflect the significant role air pollution plays in cardiovascular illness and death.

Addressing Air Pollution

• Addressing air pollution, which is the second-highest risk factor for noncommunicable diseases, is key to protecting public health. Most sources of outdoor air pollution are beyond the control of individuals and this demands concerted action by local, national, and regional-level policy-makers working in sectors such as energy, transport, waste management, urban planning, and agriculture.
• There are many examples of successful policies that reduce air pollution. For industry, clean technologies that reduce industrial smokestack emissions and improved management of urban and agricultural waste, including the capture of methane gas emitted from waste sites as an alternative to incineration (for use as biogas) can be implemented. For energy, ensuring access to affordable clean household energy solutions for cooking, heating, and lighting can be done.
• For transport, shifting to clean modes of power generation, prioritizing rapid urban transit, walking, and cycling networks in cities as well as rail interurban freight and passenger travel, shifting to cleaner heavy-duty diesel vehicles and low-emissions vehicles and fuels, including fuels with reduced sulfur content can be done.
• For urban planning, improving the energy efficiency of buildings and making cities more green and compact, and thus energy-efficient can be done. For power generation, increased use of low-emissions fuels and renewable combustion-free power sources (like solar, wind or hydropower), co-generation of heat and power, and distributed energy generation (e.g. mini-grids and rooftop solar power generation) can be done.
• For municipal and agricultural waste management, strategies for waste reduction, waste separation, recycling and reuse or waste reprocessing, as well as improved methods of biological waste management such as anaerobic waste digestion to produce biogas, are feasible, low-cost alternatives to the open incineration of solid waste.
• For health-care activities, putting health services on a low-carbon development path can support more resilient and cost-efficient service delivery, along with reduced environmental health risks for patients, health workers, and the community.

Pollutants

• Particulate matter (PM) is a common proxy indicator for air pollution. There is strong evidence for the negative health impacts associated with exposure to this pollutant. The major components of PM are sulfates, nitrates, ammonia, sodium chloride, black carbon, mineral dust, and water. Carbon monoxide (CO) is a colorless, odorless, and tasteless toxic gas produced by the incomplete combustion of carbonaceous fuels such as wood, petrol, charcoal, natural gas, and kerosene.
• Ozone (O3) is a highly reactive gas that is a major component of smog. Exposure to ozone can cause respiratory problems such as bronchitis, asthma, and emphysema. Nitrogen oxides (NOx) are a group of gases that are produced by burning fossil fuels at high temperatures. These gases can contribute to the formation of smog and acid rain. Sulfur dioxide (SO2) is a gas that is produced by burning fossil fuels that contain sulfur. Exposure to high levels of SO2 can cause respiratory problems and can contribute to the formation of acid rain.

Policies to Reduce Air Pollution

• To reduce air pollution, governments and policy-makers must take action to address the sources of pollution. This can include implementing regulations and policies to reduce emissions from industry and transportation, promoting clean energy, and encouraging sustainable urban planning. Additionally, individuals can take steps to reduce their own exposure to air pollution by choosing to use public transportation or walk or bike instead of drive, using energy-efficient appliances, and properly disposing of waste.

Synopsis

outdoor air pollution is a major environmental health problem that affects people in all countries. Fine particulate matter is the main cause of premature death due to air pollution and people living in low- and middle-income countries disproportionately experience the burden of outdoor air pollution. Addressing air pollution, which is the second-highest risk factor for noncommunicable diseases, is crucial to protecting public health. There are many examples of successful policies that reduce air pollution, such as clean technologies, clean energy, and sustainable urban planning.