Air Pollution: Understanding Particulate Matter And Its Causes

Air pollution is a public health emergency, causing an estimated 6.7 million premature deaths globally each year. One of the main causes of air pollution is particulate matter (PM), a mix of tiny solid and liquid particles that are in the air we breathe. These particles are emitted from both human activities and natural sources, such as the combustion of carbon-based fuels, vehicle emissions, industrial sites, and wildfires. PM can be of different sizes, with PM2.5 and PM10 being the most common in regulatory frameworks due to their health impacts. These fine particles can be inhaled deep into the lungs, causing serious health issues such as respiratory and cardiovascular diseases, adverse perinatal outcomes, and lung cancer.

Outdoor sources of particulate matter include vehicle exhaust, burning wood, gas, and other fuels

Outdoor air pollution is a serious issue, with particulate matter (PM) being a key concern. This matter is a complex mixture of tiny particles and liquid droplets, made up of various chemical components, and is a major contributor to haze and air quality issues. PM can be directly emitted into the air, but it can also be formed through

Indoor sources include tobacco smoke, cooking, burning candles, incense, and household cleaning products

Indoor air pollution is a significant issue, often with concentrations of pollutants being 2 to 5 times higher than outdoor levels. This is particularly concerning as people typically spend the majority of their time indoors, and so are at greater risk of the adverse health effects associated with particulate matter.

Tobacco smoke is a major contributor to indoor air pollution. Second-hand smoke is a serious health hazard, containing over 7000 chemicals, including particulate matter, with 70 of these chemicals known to cause cancer. The particulate matter in tobacco smoke is made up of a range of sizes, from large particles that quickly settle, to ultrafine particles that can be inhaled deep into the lungs and even enter the bloodstream. Children are especially vulnerable to the effects of second-hand smoke, which can cause respiratory infections, asthma, ear infections, and sudden infant death syndrome.

Cooking, especially with

Particulate matter is a mixture of solids and aerosols composed of small droplets of liquid, dry solid fragments, and solid cores with liquid coatings

Particulate matter, or PM, is a mixture of solid particles and liquid droplets found in the air. It is a complex mixture of solids and aerosols composed of small droplets of liquid, dry solid fragments, and solid cores with liquid coatings. The term fine particles refers to PM2.5, which are particles or droplets in the air that are 2.5 micrometres or less in width. These fine particles are so small that they can travel deeply into the respiratory tract, reaching the lungs and causing a range of adverse health effects.

PM2.5 is composed of a variety of chemical species, including inorganic ions, metallic compounds, elemental carbon, organic compounds, and compounds from the earth's crust. It is often associated with outdoor air pollution, particularly in cities and rural areas, and has been linked to premature deaths worldwide due to cardiovascular and respiratory diseases and cancers. Indoor sources of PM2.5 include tobacco smoke, cooking, burning candles or oil lamps, fireplaces, and fuel-burning space heaters. Outdoor sources include vehicle exhaust, burning wood, gas, and other fuels, as well as wildfires.

PM10, or inhalable coarse particles, are particles with diameters between 2.5 and 10 micrometres. While the health effects of long-term exposure to PM10 are less clear, studies suggest a link to respiratory mortality. Short-term exposures to PM10 have been associated with the worsening of respiratory diseases, including asthma and chronic obstructive pulmonary disease (COPD).

The major components of PM are sulfates, nitrates, ammonia, sodium chloride, black carbon, mineral dust, and water. Policies and technologies exist to reduce air pollution and PM levels, such as clean technologies, improved waste management, access to clean household energy solutions, and the use of low-emission vehicles and fuels.

The effects of particulate matter on human health are well-documented. In addition to the increased risk of respiratory and cardiovascular issues, studies have linked PM exposure to increased mortality, particularly in vulnerable populations such as children, the elderly, and individuals with pre-existing heart or lung diseases. To protect their health, individuals can monitor air quality and limit their outdoor activities during periods of poor air quality.

Particulate matter is associated with increased mortality, especially in vulnerable subpopulations such as people of colour and older adults

Particulate matter (PM) is a mixture of solids and aerosols composed of small droplets of liquid, dry solid fragments, and solid cores with liquid coatings. PM is not a single pollutant but a complex mixture of many chemical species. It is defined by the diameter of the particles for air quality regulatory purposes. Those with a diameter of 10 microns or less (PM10) are inhalable into the lungs and can induce adverse health effects. Fine particulate matter is defined as particles that are 2.5 microns or less in diameter (PM2.5).

PM2.5 is associated with increased mortality, especially in vulnerable subpopulations such as people of colour and older adults. Short-term exposures (up to 24 hours) to PM2.5 have been linked to premature mortality, increased hospital admissions for heart or lung causes, acute and chronic bronchitis, asthma attacks, emergency room visits, respiratory symptoms, and restricted activity days. These adverse health effects have been reported primarily in children and older adults with pre-existing heart or lung diseases. Long-term exposure to PM2.5 has been linked to premature death, particularly in people with chronic heart or lung diseases.

Research has found that people of colour in the United States are disproportionately exposed to PM2.5, a regulated air pollutant. This disparity in exposure holds across income levels and regions of the US. As a result, communities of colour experience higher rates of pediatric asthma and premature mortality due to PM2.5 and other pollutants. The relative disparity in premature deaths caused by exposure to fine particulate matter between the least and most white communities in the US increased by 16% in the last decade. Similarly, the disparity between the least and most Hispanic communities increased by 40% during the same period.

Older adults are also vulnerable to the health risks associated with PM2.5 exposure. Long-term exposure to PM2.5 has been linked to reduced lung function growth in children and adverse health effects in older adults with chronic heart or lung disease. This is because older adults, especially those with pre-existing conditions, are more susceptible to the harmful effects of air pollution.

Overall, vulnerable subpopulations such as people of colour and older adults are disproportionately affected by the increased mortality risks associated with PM2.5 exposure. This highlights the need for effective policies and interventions to reduce air pollution and protect the health of these vulnerable communities.

Actions to reduce indoor PM exposure include using air conditioning, particulate filters, and limiting smoking

Particulate matter (PM) is a mixture of solid and liquid particles suspended in the air. It is a common proxy indicator for air pollution. PM2.5 and PM10 are the two main categories of particulate matter. PM2.5 refers to particles with a diameter of 2.5 microns or less, while PM10 refers to particles with a diameter of 10 microns or less. Both types can be inhaled and cause adverse health effects, with PM2.5 being more harmful due to its ability to reach the deeper parts of the lungs.

Scientific studies have linked indoor PM exposure to various health issues, including eye, nose, and throat irritation, aggravation of heart and respiratory diseases, and premature death in individuals with pre-existing heart or lung conditions. Children, older adults, and those with heart and respiratory issues are particularly vulnerable to the harmful effects of PM.

To reduce indoor PM exposure, several actions can be taken:

• Use air conditioning: Window or portable air conditioners can help reduce indoor particle levels if they recirculate air. For central air conditioning systems, set the system to "on" instead of "auto" to ensure constant air filtration.
• Improve ventilation: Open windows or doors to allow fresh air to circulate indoors and dilute PM concentrations. When using printers or copiers, which can generate PM, ensure proper ventilation by opening windows or using a local exhaust fan.
• Utilize particulate filters: Install higher-efficiency filters in your heating, ventilation, and air conditioning (HVAC) system. Regularly change filters on central heating and cooling systems according to the manufacturer's instructions. Portable air cleaners can also help improve indoor air quality.
• Limit smoking: Do not allow smoking indoors. If smoking is unavoidable, it should be done outside and away from windows and doors to prevent second-hand smoke from entering the home.
• Reduce indoor combustion sources: Avoid burning candles, incense, or wood indoors. Ensure that all fuel-fired combustion appliances, such as stoves, heaters, and furnaces, are vented to the outdoors.
• Minimize indoor cooking emissions: Use stove range hoods while cooking and keep them vented to the outdoors. Cook on the back burners whenever possible to improve airflow and reduce PM release. Avoid burning or charring food, and use cooking oils with higher smoke points when cooking at high temperatures.

By implementing these measures, individuals can effectively reduce their exposure to indoor particulate matter and mitigate the associated health risks.

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